Central Agricultural University, College of Post Graduate Studies in Agricultural Sciences, Umiam

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Browsing Central Agricultural University, College of Post Graduate Studies in Agricultural Sciences, Umiam by Subject "Genetics and Plant Breeding"

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    ThesisItemOpen Access
    Agro–morphological characterization and genetic diversity analysis of aromatic rice (Oryza sativa L.) genotypes using SSR Markers.
    (College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2019-03) Pramod Kumar; Singh, K. Noren
    Rice (Oryza sativa L.) has been referred as “Global Grain” and it is the most important cereal crop belonging to Poaceae family with chromosome no. 2n = 24. Being rich in flora and fauna, the North East Region of India is home to various locally adapted aromatic and quality land races of rice viz. Joha, Chakhao and Tai cultivars grown in the states of Assam, Manipur and Mizoram respectively and a number of other aromatic rice cultivars are also grown in the states of Sikkim and Tripura viz. Krishna Bhog, Brimphul, Kalanunia and local Basmati. The basic requirement of a crop improvement programme is the information on extent of variation, estimates of heritability and genetic advance in respect to yield and yield contributing traits. Therefore, characterization of germplasm is of great significance for current and future agronomic and genetic improvement of the crop. The present study entitled “Agro–morphological characterization and genetic diversity analysis of aromatic rice (Oryza sativa L.) genotypes using SSR markers” was conducted to evaluate a set of aromatic rice based on agro-morphological traits and SSR markers. A total of 42 different aromatic rice genotypes including 4 check varieties and 26 SSR markers were used in the experiment. All the selected genotypes were evaluated in an augmented experimental design. A total 51 traits both morphological and quantitative nature were recorded. Grain yield per plant is significantly correlated with numbers of effective tillers and number of seeds per panicle. The analysis of variance showed that all the quantitative traits under study except effective tillers per plant were highly significant value at 1% and 5% level of probability. The genetic distance between the 42 accessions of aromatic rice ranged from 0.03 to 0.87. Out of 26 primers used 16 polymorphic primers. Genotype RM495 (82.6%) recorded highest per cent of polymorphism whereas RM124 (2.4%) recorded lowest per cent of polymorphism. Out of 42 aromatic genotypes of rice IC-342368 and IC-401209 were maximum genetic distance on the basis of morphological analysis. Whereas, maximum genetic dissimilarity was found between IC-137401 and Ja-Shulia genotypes. The genetic dissimilarity between the 42 accessions of aromatic rice ranged from 0.06 to 0.42. Hence it will be used as further breeding programme as a new tools in favour of crop improvement.
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    ThesisItemOpen Access
    Assessment of genetic variation in lentil (Lens culinaris Medik) for its agronomic performance, aluminium tolerance and phosphorus uptake efficiency
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2021-02) Devi, Puthem Victoria; Singh, K. Noren
    The present investigation is carried out to identify the better performing and most suitable genotypes in yield and its component traits to develop new and improved varieties with Al tolerance and P uptake efficiency in acidic soil. The study was conducted using 20 lentil genotypes collected from IARI, New Delhi. Pooled Analysis of variance for 11 agronomic parameters showed highly significant GxS interaction effect among the genotypes whereas most of the genotypic variances showed non-significant average effect against GxS interaction. Highest mean square values were observed for plot yield and then after in no. of pods per plant. Among all the characters, the highest PCV values were observed in grain yield per plant followed by plot yield and no. of pods per plant. Highest GCV values were recorded 1000 seed weight followed by days to 50 % flowering and grain yield per plant. 1000 seed weight followed by days to 50 per cent flowering were recorded with highest broad sense heritability. Greater genetic advance was recorded in the traits 1000 seed weight, moderate in days to 50% flowering whereas other character showed low genetic advance. PDL-1 (192.64 g/plot) was the best performing genotype for plot yield followed by L-7903 (190.49 g/plot) and PAL-7 (180.89 g/plot) whereas BM-4 (65.02 g/plot) was seen to be the least performing genotype followed by PAL-3 (77.19 g/plot). Plot yield showed highest positive and significant correlation with grain yield per plant succeeded by biological yield per plant, number of pods per plant followed by plant height. Path analysis also revealed highest positive direct effects followed by biological yield per plant and number of pods per plant with plot yield. Highest positive indirect effects were observed between biological yield per plant followed by number of pods per plant to plot yield. The negative indirect effects to plot yield were very low and negligible. Residual effects of 04.75 % indicated that there were some unknown effects which influenced the plot yield. Grouping of genotypes into clusters with D² values were performed by using Tocher’s method. Three clusters were formed with cluster I consisting of 17 genotypes, cluster II having 2 genotypes and cluster III with only one genotype. The distantly related inter-cluster was found between cluster III and cluster II resulting wider diversity between groups which could be useful for further breeding programme while least in between cluster III and cluster I indicating less diversity. Highest intracluster distance was found in cluster II showing more heterogeneity among the genotypes in the groups. Further observations were carried out under hydroponic condition to check the better performing genotypes in low pH and Al treated medium and scoring was done based on staining intensity as no stain, light, medium and dark. The maximum root regrowth was recorded in L7903, L-4602 and PDL-1 which were also stained light by hematoxylin staining. A linear regression line depicted the significant and positive regression between primary root regrowth and yield. Further growth response study was conducted in hydroponic culture medium to understand performance of different lentil genotypes in acidic and Al treated condition. Genotypes PAL 6 gave the longest primary root length, total root length and total root surface area in 7 days after treatment; however, L-7903 was recorded for highest root dry weight, shoot dry weight and total root volume while the least performing genotype was VL-126. ANOVA for short term showed highly significant variation among the genotypes studied. Highest value of GCV and that of PCV was obtained from total root volume, and broad sense heritability and genetic advance was highest in case of root dry weight. Phosphorus uptake efficiency was estimated and it was highest in DPL-62, VL-126 and PDL-1 and lowest in PAL-5 under field condition. Moreover, the highest PUE under Al treated hydroponic condition was shown by L7903 succeeded by PDL-1 and L-4147 and lowest was obtained from PAL-7. Analysis of variance for PUE in both field and hydroponic medium showed highly significant variation between the genotypes. GCV, PCV, broad sense heritability, genetic advance was higher in field condition than hydroponic condition. From the experimental findings, it can be concluded that characters which were positively correlated with yield would be useful to the breeders for crop improvement programme and more diverse genotypes could be used for hybridization work. Moreover, genotypes which showed tolerant to Al and higher PUE in acidic soil could be used for hybridization and also for molecular studies to justify which genes involved in tolerance to stress environment and which genes would be responsible for higher uptake of P from the P deficient environment for further breeding studies.
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    ThesisItemOpen Access
    Characterization and evaluation of advanced breeding lines of lowland rice with respect to agro-morphological traits
    (College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Imphal, 2018) Rai, Ashish; Rai, Mayank
    Rice (Oryza sativa L.) is the primary food source for more than a third of the world’s population. There is an urgent need of developing HYVs to increase rice productivity in India as well as North Eastern Hill Region. The present investigation was carried out to evaluate twenty four breeding line of rice with respect to performance, variability, heritability, character association and genetic divergence of sixteen qualitative characters and sixteen quantitative characters. The experiment was laid out at CPGS Campus, Umiam, Meghalaya in a randomized block design with three replications during kharif season, 2017. Visual observations were recorded on five plant basis as per standard descriptors on sixteen qualitative characters viz., basal leaf sheath color, leaf auricle, leaf ligule, ligule shape, leaf collar, flag leaf: attitude of blade, leaf sheath anthocyanin colouration, leaf blade: anthocyanin, panicle secondary branch, leaf senescence, spikelet: color of tip of lemma, panicle: exsertion, panicle: awns and lemma: anthocyanin coloration of area below apex. Data were recorded on days to 50% flowering, plant height, tillers per plant, panicle per plant, panicle length, leaf length, leaf width, leaf area index, canopy temperature, biological yield, spikelet per plant, no. of grains per plant, spikelet fertility (SF), harvest index, 1000 grain weight and grain yield per plant. Analysis of variance indicated the existence of significant differences among genotypes for all the characters studied except leaf width and harvest index. The characters viz., days to 50% flowering, leaf length, leaf width exhibited high heritability and panicle per plant, canopy temperature, spikelet per plant, no. of grains per plant, spikelet fertility, harvest index, and yield per hectare exhibited medium heritability. Character association studies revealed significant and positive association of grain yield per plant with tillers per plant, panicle per plant, no. of grains per plant, spikelet fertility. Therefore, these characters could be used as criteria for selection of genotypes with high seed yield. Path coefficient analysis revealed highest direct effect on grain yield for number of grains per panicles and 1000 grains weight.1000 grains weight exhibited strong positive direct effect on seed yield, however, it contributed negatively seed yield through number of grains per panicle. Based on 16 quantitative character and 16 qualitative character Euclidean distance was calculated between each set of progeny and the two checks. The maximum distance was observed between CAUS122 and CAUS110 and minimum distance was observed between CAUS120 AND CAUS106. Clustering analysis led to the grouping of lines into 2 major groups. Both the checks were grouped in second cluster which was further dividing in 3 sub-clusters. Based on per se performance with respect to yield components, blast resistance and divergence, CAUS105, CAUS104, CAUS107, CAUS121 were identified as the best progenies that could be nominated for multilocation trials, or used as parents for further population improvement.
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    ThesisItemOpen Access
    Characterization and evaluation of some genotypes of soybean [Glycine max(L.) Merrill] under acidic soil condition in Meghalaya / by
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2019) Devi, Yenkhom Linthoingambi; Singh, K. Noren
    In the world scenario, India is holding 5th position by contributing about 3.95% share in total production of soybean. Although soybean is considered an important oilseed crop in the world, its production in North-eastern region of India especially in Meghalaya is quite less due to its acidic soil condition. This necessitates the requirement of better performing genotypes along with the study for genetic diversity of genotypes to develop new and improved cultivars. In the light of the above fact, the present research was conducted using 40 different soybean genotypes from different regions in the country. At different growth stages of the plant, 22 DUS characters and 12 quantitative characters were recorded. Analysis of variance gave highest significant value for number of seeds per plant succeeded by number of pods per plant and the lowest was found for number of seeds per pod and primary branches per plant. Among all the characters which were found to have high heritability, days to maturity and number of pods per cluster had the highest value. Number of seeds per plant showed highest genetic advance with high GCV, PCV and heritability followed by number of pods per cluster. Studying the correlation analysis of the agronomic traits, seed yield per plant was showing positive correlation with characters viz., number of seeds per pod, number of pods per plant, 50% flowering, plant height, days to maturity, primary branch as per plant and protein content while characters like number of seeds per pods, number of pods per cluster and 100 seed weight was found nonsignificant. The maximum yield per plant was recorded in the genotype TS-53 followed by SKF-SPS-11 and MACS-1493. Lowest yielder genotypes were MACS-1575 followed by NRC-130. Genotype CSB-10112 had the highest protein content (45.1%) and genotype NRC-131 was found to have highest oil content (20.1%). Clustering of genotypes for studying genetic diversity was performed by Tocher’s method of clustering in D2 analysis. A total of 4 clusters were formed with cluster I having 23 genotypes, cluster II with 4 genotypes, cluster III with 3 genotypes, cluster IV with 5 genotypes while cluster V, VI, VII, VIII and IX had one genotype each and remained distinct individually. Highest inter-cluster distance was found between the cluster VI and IX suggesting wider diversity between the groups and thus, could be used for hybridization programme and lowest was found between the cluster IV and V showing less diversity between them. Highest intra-cluster distance was recorded by the cluster IV indicating greater heterogeneity among the genotypes. Further, study was carried out to identify the better performing genotypes in the acidic condition through hydroponic study for tolerance to Al toxicity by using two concentrations of 25μM and 75μM Al solution along with the re-growth study in the latter. The ranking of genotypes based on yield performance was closely related with ranking based on the re-growth length of the genotypes after treatment. Linear regression of difference in taproot length of treated root from the control solution was negatively regressed to the yield data and that of root regrowth was found positively regressed to the yield data. Since, it is a preliminary finding; further validation in repeated trials might be useful for further strengthening of the relationship between hydroponic performance and yield performance under acidic soil. With these findings, it will be useful for breeders as they can use the characters which were found positively correlated with yield as selection criteria in crop improvement work and the diverse parents could be used for hybridization work. Also, the genotypes showing tolerance to Al toxicity could be used for further molecular level analysis to find the gene responsible for tolerance and also for further field analysis.
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    Characterization of rice bean genotypes through morphological, molecular and biochemical parameters
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-09) Kumari, V. Preeti; Philanim W. S.
    Rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi] previously known as Phaseolus calcaratus is an under-exploited and neglected tropical legume crop, cultivated on small areas of North eastern hilly areas. As northeastern region has enormous diversity the genetic potential of indigenous germplasms needs to be better exploited to increase yield potential of the crop and to select suitable parents for different breeding programs. Being a lesser-known crop, information available on its nutrient composition and antinutritional status is also limited. Considering the need to understand the genetic diversity present in rice bean for potential usage in future crop improvement programmes and realization of its nutritional benefits through characterization of the material, this study was undertaken with the objective to characterize rice bean germplasms based on morphological traits, molecular analysis and biochemical traits. 92 rice bean genotypes collected from several northeastern regions and NBPGR, Shimla were evaluated at the experimental farm (Plant breeding, ICAR-RC NEH) for eighteen morphological traits. It was observed that Number of clusters per plant (CPP), number of pods per plant (PPP), number of pods per cluster (PPC) had high genotypic coefficient of variation (GCV) (>20%). Traits like number of pods per plant (PPP), pod length (PL), pod width (PW) and 100 seed weight (HSW) showed positive correlation with seed yield per plant as well as positive direct effect on it. Molecular characterization of the genotypes was carried out with 43 SSR markers among which 14 markers were found to be polymorphic. CG8775c0 showed maximum genetic diversity and PIC value as well as cG25883c0 showed maximum heterozygosity for current set of genotypes. Analysis of molecular variance showed maximum variation within population among individuals and population structure analysis revealed that present set of genotypes were grouped into two clusters (K=2). Ten genotypes were selected from the collection for biochemical estimation of proximate content of crude fat, crude protein, crude fiber, total carbohydrate, moisture, ash, energy, phytic acid, total flavonoids and total antioxidant capacity. In biochemical characterization traits like crude fat (0.30-1.80%), crude protein (19.34-26.03%), crude fiber (1.27-2.87%), ash (0.77-2.76%), carbohydrate (57.98-69.59%), phytic acid (0.501-1.312g/100g) and total flavonoids (5.93-9.97mg QE/g) varied significantly among genotypes under study. Among current set of genotypes, the genotype collected from Mizoram (Bete-14 and Bete-9), Manipur (Ukrul-14) and Meghalaya (LRGP-8) were high yielders as well among checks RBL-6 was high yielder. Biochemical estimation revealed maximum crude protein, crude fat, carbohydrate and antioxidant capacity in Bete-14. Least phytic acid was observed in Bete-14 followed by IC521087 which had maximum crude fat, crude fiber and energy. IC341987 recorded maximum flavonoids and antioxidant capacity but least phytic acid. Hence, the morphological traits which showed positive correlation with seed yield per plant as well positive direct effect on yield need to be emphasized as effective selection criteria for yield improvement in rice bean. Further polymorphic markers with high PIC will help in better distinguishing among individuals at molecular level. Based on the study, it was found that rice bean is a good source of protein at par with other legumes with rich functional properties like antioxidant capacity and flavonoids. The study deciphers association among yield and its corresponding traits and helps understand the variation that exist in the crop through different genetic parameters with a better understanding of the diversity that is present at the molecular level and characterization of its nutritional parameters. The information gathered can be utilized in different selection programmes for overall genetic improvement of rice bean.
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    Combining ability studies for yield and Aluminium toxicity tolerance in Maize (Zea mays L.) hybrids
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-01) Kalita, Samudra; Sen, Devyani
    The present investigation involved field evaluation of 160 F1 hybrids generated from a Line x Tester mating design to identify good combiners. Hydroponics screening of the same 160 hybrids in presence of excess aluminum at seedling stage to identify tolerant genotypes was also done. Thirteen yield and yield contributing characters were analyzed for the field evaluation studies. The general ANOVA revealed that all cob and kernel characters were highly significant for Line x Tester interaction but the interaction for phenlogical studies were non-significant. Proportional contribution of lines and line x tester interaction in the hybrids was also high. Contribution of the testers was negligible. Combining ability variance studies indicated a preponderance of dominance variance for the cob/ kernel traits indicating that heterosis breeding would be successful. This was reflected in the results of standard heterosis with several hybrids found to be superior over checks for cob and total kernel weight. Six cross combinations with positive and high significant sca effects for multiple cob / kernel traits were identified. The parental lines of these crosses can be used to validate/assign existing/new parental lines into the respective heterotic groups. Hydroponics studies at seedling stage revealed significant presence of variation for the root and shoot characters studied. Mean values and dispersion around the mean for the different traits were higher values in control set compared to treatment for all parameters studied except number of adventitious roots developed. ANOVA was highly significant for all the traits studied implying presence of meaningful genetic variation. The top performing hybrids were better than the checks for all the parameters studied. It was seen that certain treated hybrids could perform at par with their control for the root / shoot parameters studied. Pearson's Correlation and Principal Component Analysis (PCA) studies revealed that Net Seminal Root Length was uncorrelated with all other six root/shoot parameters studied. The first two axes of PCA accounted for 71.67% of variation in the data. Majority of the top contributing hybrids in PC1 and PC2 were also top performers based on mean performance. Hematoxylin staining studies of root sections was not uniform. While root sections of some top performing hybrids took up intense stain, others took very little stain indicating differential aluminum uptake by the roots. Therefore, while the field evaluation studies could successfully identify hybrids with superior sca effects and heterosis, the variation for Al toxicity tolerance observed in this panel can be utilized to identify Al tolerant parental lines.
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    Combining ability, heterosis and path analysis studies for yield and yield attributing traits using half diallel mating design in maize (Zea mays L.)
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-11) Reddy, Tatiparthi Harsha Vardhan; Sen, Devyani
    The success of hybrid breeding programmes has been possible due to exploitation of heterosis and the foremost step in such breeding programmes is to identify potential parents for developing hybrid combinations. North East India has a rich maize diversity which can be explored for the same and the current study was one such attempt to determine the combining ability and heterosis for yield and yield contributing traits in a set of inbred lines developed from maize landraces of North East India. Thirty-five hybrids were generated using a half diallel mating design and evaluated along with 10 parents and 3 checks in Randomized Complete Block Design with two replications in the next season. Analysis of variance (ANOVA) revealed that significant variation among the genotypes for all studied traits except flowering days. The combining ability ANOVA revealed significant GCA and SCA mean squares for all traits studied except Seed Index, and Ear height was only significant for SCA mean squares. The higher SCA to GCA variances for all studied traits and GCA/SCA ratio indicated the preponderance of dominant gene action for all traits under study and heterosis breeding will be effective. Among the parental lines, P14 and P15 had positive GCA effects for all the ear/kernel related traits. Correlation study between hybrid means and SCA effects indicated significant positive correlation for most ear/kernel traits. Almost all hybrids showed superior performance for mid and better parent heterosis. Also, the SCA effects of total seed weight and ear weight (de-husked) showed significant positive correlation with better parent heterosis and mid parent heterosis. For standard heterosis, hybrid H20 was superior in performance over Check 1 for both ear and total seed weight. H20 was also at par with Check 2 for total seed weight weight. Path analysis studies revealed that the selection on the basis of ASI and ear length would weight higher ear and total seed weight. An additional aluminum stress experiment done to identify stable performers indicated that hybrids H20, H26 and H3 gave comparable results for control and treatment. In certain other hybrids like H16, H19, H29 and H15 the fluctuation in ear weight for treatment and control was much more pronounced indicating that these hybrids were highly sensitive to change in environment. Based on these studies, the low performers should be screened out and further work needs to be done on the test hybrids with higher SCA effects and parental lines with desirable GCA effects for the yield and yield contributing traits under study.
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    ThesisItemOpen Access
    Crossability studies and genetic diversity in Blackgram using molecular markers
    (College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018) Singh, Puyam Tondonba; Khanna, V. K.
    Blackgram productivity has remained low in subtropical and tropical Asia, it is important to estimate the genetic diversity in the existing cultivars in order to see if the lack of genetic variability might be the constraining factor. Crossability studies among cultivated blackgram (Vigna mungo) varieties and genetic diversity analysis using SSR markers. In the present study, a total of 35 blackgram accessions were used to evaluate the genetic diversity using 30 SSR markers. Out of these accessions, 5 random accessions were selected for the crossability studies. A total of 15 crosses were made and pollen fertility, pollen germinability and pollen tube growth rate was recorded after every 2 hours, 4 hours and 6 hours of pollination. These three parameters were used to generate a correlation matrix with pod set, to see if any abnormalities in these parameters is the cause of reduced pod set. The maximum pollen fertility between the five selected parents was observed in KU-16-33 (94.06 %) and minimum in GP-IPU-99-238 (90.35%). However, highest pod set was observed in PANT-U-6 (91.66 %). Upon selfing, maximum pollen germinability was found in PANT-U-31 (70.00%) and minimum was in PANT-U-6(62.66 %). Longest pollen tube growth was observed in PANT-U-6 (295.51 μm) and shortest in GP-IPU-99-238 (243.30μm). In case of crosses, maximum pollen germination was observed in GP-IPU-99-238 X PANT-U-6 (58.57%) and minimum in KU-16-33 X GPIPU-99-238 (51.33%). The highest pod set was observed in KU-16-33 X KU-16-26 (70.58%) and least was in KU-16-26 X GP-IPU-99-238 (54.55 %). Longest pollen tube was observed in crosses of KU-16-33 X KU-16-26 (244.11 μm) and minimum in GP-IPU-99-238 X PANT-U-31 (217.10 μm). A steady increase in pollen germination rate and pollen tube growth rate was recorded. The final reading in pollen tube growth revealed that pollen tube was almost 3-4 times than that of the initial stages. These data were subjected to Pearson’s correlation coefficient matrix which showed that there was non significant significant correlation between pollen fertility and pod set and high significant correlation was seen between pollen germinability, pollen tube growth rate with the podset. A total of 30 SSR primers were screened for genetic diversity analysis in 35 accesions of Blackgram out of which a total of 11 primers were found to be polymorphic. A total of 357 bands were generated and 119 of these bands were polymorphic with32.97% polymorphism and the rest 238 bands are monomorphic with 66.6% monomorphism. Based on the Polymorphism Information Content (PIC) value, two primers, CEDG 118 and CDEG 279 were found to be informative.The PIC value showed a range from 0.109 to 0.582. The observation recorded on all the molecular data were subjected to simple matching coefficient. The genetic similarity between the 35 accessions of blackgram was assessed by simple matching coefficient and it ranged from 0.14 to 0.78. The least genetic similarity was observed between the genotypes KU-16-30 and KU-16-33 with a coefficient of 0.82.These two accessions could be used for breeding purpose for crop improvement. The greatest similarity was observed between the accessions GP-PGRU-9514 and GP-134.16.50 748 having a coefficient of 0.14. These data were used to generate a Neighbor Joining tree. In the factorial analysis plot, the first axis in the plot explained 18.66 % variation, second, third, fourth and fifth components explained 12.36 %, 9.95 %, 7.66 % and 6.44 %, respectively among the 35 accessions of Blackgram. The five components explained a total of 55.17 % of total variation.
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    ThesisItemOpen Access
    Crossability, embryo rescue and genetic diversity studies in Oryza
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2019-09) Dabi, Talom; Khanna, V. K.
    Rice comes under the genus Oryza and family Poaceae. The mode of pollination of cultivated Oryza species is primarily self-pollination with limited degree of outcrossing. Wide crossing offers an approach for widening the gene pool of cultivated rice and exploring the new gene combinations available for crop improvement. The extent to which the genes get exchanged between the donor and recipient parent is based on crossability and reproductive barriers where reproductive barriers can be divided into pre-fertilization and post-fertilization barriers. Technique such as in vitro embryo rescue can be employed to facilitate hybrid production. Knowledge of genetic structure and diversity of uncharacterised rice varieties along with wild rice is key for efficacious utilization of genetic resources. The likes of DNA markers such as SSR have been used in genetic diversity studies. The present study was carried out to find the crossability between various accessions, varieties and species of rice; to obtain the correlation between pollen germination, pollen tube growth and abnormal pollen tubes with seed set; to get interspecific hybrids by embryo rescue; to confirm the hybridity by molecular markers and to assess the genetic diversity of the rice material using SSR markers. Crossability and pollen studies revealed that among all the inter-varietal crosses, “CAU R1 X Shahsarang” gave the best results in terms of seed set (58.39%), percent pollen germination (43.40 ; 60.09) and pollen tube growth (125.81 μm ; 562.81 μm) respectively at different time intervals (10 minutes ; 60 minutes after pollination). For wide crosses, highest seed set was obtained in Pathara X Oryza rufipogon (7.34%) and this same cross combination had longest pollen tube at 10 minutes (105.73 μm) and 60 minutes (385.56 μm) after pollination respectively. Percent pollen germination at 10 minutes and 60 after pollination was highest in Govind X O. rufipogon (37.30%) and (60.60%) respectively. Pearson correlation coefficient for various pollen characters with seed set revealed significant and positive values at 0.01** and 0.05* probability level except for the pollen viability.Embryo rescue was employed to get interspecific hybrids with zero percent seed set. Out of eight cross combination, only three wide cross combination showed success to embryo rescue procedure. Cross combination “Tejaswini X O. rufipogon” (63.63) showed best embryo germination percentage followed by “Pant Dhan 19 X O. meriodinalis” (46.15). Hybrids were confirmed by SSR markers. Genetic diversity study of forty-three rice genotypes using thirty- one SSR markers produced a total of 113 alleles with average number of alleles per locus (3.65). RM336 revealed highest PIC value of 0. 708 and RM304 revealed lowest value of 0.202. This concluded that RM336 along with other SSR markers with high PIC value can be effectively used for genetic diversity analysis in various rice germplasm. Pairwise dissimilarity matrix based on simple matching coefficient of 43 rice germplasm derived from SSR markers data showed highest dissimilarity index of 0.90 (IC- 332760 and Jangiya) and lowest index of 0.19 (PB-1612 and SR/RJ-3).These genotypes with high dissimilarity index can be selected as parents due to their diverse nature in future crossing programs.
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    ThesisItemOpen Access
    Crossability, embryo rescue and genetic diversity studies using molecular markers in cultivated Soybean & its wild relatives.
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2019-09) Cherian, Billy; Khanna, V. K.
    Soybean (Glycine max (L.) Merrill) cultivation in India dates back to first century AD, however commercial cultivation of Soybean in India started only a few decades ago with unprecedented growth in the cultivated area and total production. In the present scenario of oilseed production in India, Soybean is the leading crop which is grown over 10.69 million hectares with total production of 14.66 million tonnes. Being a self-pollinated crop with limited outcrossing, genetic base of Soybean is considered to be very narrow. Considering these facts, the present study was conducted to understand the genetic diversity of popular Soybean germplasms in India and to study its crossability behavior. Since the genetic base of Soybean is narrow, use of wild relatives in the breeding program is a good strategy to improve its gene pool. Considering this, two wild relatives of Soybean were used in the study to understand its crossing behavior with cultivated Soybean and to produce hybrids with it. Genetic diversity studies using 36 polymorphic SSR markers revealed that the genotypes used in this study is clustered into three major clusterswhere cluster 2 and 3 having majority of genotypes, hinting the high genetic relatedness of Soybean genotypes. Polymorphic Information Content (PIC) values of these SSRs ranged from 0.3119 to 0.6836, where Satt588 (0.6836) having the highest PIC value and considered to be highly informative. Crossability studies were conducted using six genotypes viz. Kalitur, Alankar, MAUS 1, ADT 1, PS 1024 and Bragg and two wild relatives viz. Glycine soja and Glycine tomentella. High pollen viability of 94.10% was observed in Kalitur but pod set was 86.4 9%, whereas PS 1024 was giving 91.40% pod set and pollen viability of 91.10% in case of selfing. Wild relatives showed lesser pollen viability and pod set percentage (G. tomentella 78.20 % & 61.30%, G. soja 83.70% & 77.10%) compared to the selfing of cultivated varieties. Crosses between these germplasms shown lesser pod set compared to selfing. Interspecifichybridization was carried out by selecting best performers in intervarietal crosses and used them as female parents, whereas wild relatives where used as pollen parents. G. soja when crossed with Bragg, Kalitur and Alankar gave pod setting although it was less than 10% in all the cases, whereas G. tomentella could not produce any mature pods due to embryo abortion. Putative hybrid pods of the G. tomentella hybrids were used for embryo rescue procedure and out of 19 embryos cultured 8 were able to be rescued and hardened. Hybridity status of the rescued plants were identified by polymorphic SSR marker Satt396. The present study could reveal the possibility of using the wild relatives to improve the genetic base of Soybean in future breeding attempts. The untapped potentials hide within the wild perennial relatives of Soybean will be the future of Soybean breeding programmes and will be helpful in increasing the genetic base of the cultivated elite breeds.
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    Divergence analysis of advanced breeding lines of rice in terms of SSR markers, yield and grain quality characteristics
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-03) Lokeshkumar K; Rai, Mayank
    The present study was carried out to estimate the genetic variability and diversity among advanced breeding lines of rice along with two checks (CAUR1 and Shasharang) for yield and yield attributing traits, grain quality traits and SSR markers. Agronomic data obtained from 52 advanced breeding lines and two checks were analysed using ANOVA for various yield and yield attributing traits revealed significant variance among the lines. PCA analysis for yield and yield attributing traits showed that the first five principal components contributed for about 94.06 % of the total variation. Grain quality for 78 advanced breeding lines along with two checks varied significantly for all the traits studied. Seed length (6.040 to 12.172 mm), seed breadth (1.796 to 4.243 mm), seed length breadth ratio (1.81 to 5.38), kernel length (5.005 to 10.084 mm), kernel breadth (1.632 to 3.403 mm), kernel length breadth ratio (1.70 to5.19), grain length after cooking (6.116 to 11.241 mm), linear elongation ratio (1.00 to 1.99), amylose content (14.59 to 29.03 %), protein content (5.09 to 11.02 %) differed significantly. 40 lines showed no grain chalkiness, while 17 lines with less chalkiness and 23 lines with high chalkiness were identified. Alkali spreading value is negatively correlated with Gelatinization Temperature (GT). Based on gelatinization temperature, the advanced breeding lines were classified into three groups: 55 with high GT, 10 were intermediate, and 15 lines had low GT. PCA analysis for grain quality traits showed that the first seven principal components contributed for about 87.40 % of the total variation. 36 selected advanced breeding lines along with two checks were characterized using 27 SSR markers. Out of 27 SSR markers, 14 markers were found to be polymorphic and 13 markers were monomorphic. RM154 exhibited maximum number of amplicons with 5 alleles, followed by RM152, RM271, RM125 with 4 alleles each, followed by RM237, RM413, RM431, RM447 with 3 alleles each, followed by RM44, RM124, RM161, RM215, RM495, RM514 with 2 alleles each. The 38 rice cultivars were grouped into 12 major clusters, where cluster 1 and 2 comprised of highest number of lines with some minor groups. Cluster 3 with 4 lines, cluster 4, 5, 6 and 7 with 2 lines each, remaining five lines clustered independently. STRUCTURE analysis (K=5) revealed that majority of the lines were characterised as admixtures. This indicates that the group of advanced breeding lines carry new combination of alleles and are genetically diverse. With the availability of more genetic diversity within improved lines for morphological, yield components and quality traits, increased genetic gain can be achieved through hybridization based rice improvement programme.
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    ThesisItemOpen Access
    Divergence and combining ability studies in a set of inbreds developed from maize landraces of North Eastern Hill (NEH) Region of India.
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2019-12) K. L., Naveen Kumar; Sen, Devyani
    An efficient hybrid maize development programme in the North Eastern Hill Region (NEHR) of India would focus on development of parental inbreds from available indigenous germplasm followed up by divergence studies for exploiting available genetic diversity for heterosis. The present study spanning seven cropping seasons from Kharif-2016 to Kharif-2019 focused on inbred development, divergence and combining ability studies in landraces originating from different states of NEHR. Of the 213 inbreds originating from landraces designated as M9, M22, Ma5, N11, N25, S16 and T9 which could be subjected to four rounds of sib mating followed by two generations of selfing, a subset of 111 lines were further used for divergence studies. Almost all of the thirteen traits studied recorded inbreeding depression studies in accordance with the expected increase in homozygosity with the exception of days tasseling and days to siliking which increased as a result of inbreeding for lines originating from M9 and T9. Inbreeding depression rates for the remaining lines were variable and registered a gradual increase in homozygosity. Divergence studies using 48 SSR markers were taken up in S6 generation for the subset of 111 inbred lines selected on the basis of higher ear weight. Thirty eight markers were found to be informative and used for further analysis. With a mean of 2.32 alleles per locus, the average PIC value for the informative markers was 0.38. A total of 88 alleles were detected with observed heterozygosity for the lines studied ranging from 0 to 29.1% for the 38 SSR markers under study. High overall Fst (co ancestry) values were positively correlated with high Fis (inbreeding) values for 22 of the 38 loci coupled with significantly reduced heterozygosity. When corrected for bias in small populations, Hedrick's standardized Gst (G''st) stood at 0.263 indicating significant population substructuring. The gene flow (Nm) was restricted for loci with high Fst values. STRUCTURE analysis grouped the 111 inbreds into two distinct and one admixture subgroup designated as Populations I (26 individuals), II (62 individuals) and III (23 individuals). The larger subgroup i.e. Population II could be further subdivided into sub populations Pop-M9 and Pop-T9. The subgroups when visualized using PCoA could explain 31.26% of the variation and indicated that Population I was the most variable. AMOVA supported by Fst coefficients indicated 17% structuring among populations with maximum variation detected for individuals within populations. Un-weighted Neighbour Joining cluster analysis also distinguished individuals of Population I and II into three distinct clusters with maximum genetic distance recorded for lines between individuals of Population I and Pop-T9. These studies coupled with high morphological variability in yield related traits in the different subgroups indicate significant departure from panmixia. Based on the divergence, ten inbreds were selected for combining ability studies. The 41 hybrids generated were evaluated along with three commercial checks (DMH-121, CMH08-292 and Bio-9544) over two seasons (Rabi-2018 and Kharif-2019) in a Randomized Block Design (RBD) with two replications. Fifteen yield and yield contributing traits were studied and pooled analysis indicated highly significant G x E interaction. The ratio of gca/sca variance lesser than unity in both seasons indicated preponderance of non-additive gene action. Based on the significant gca effect identified three good general combiners, Y-M2, Y-N6, Y-S9 for Rabi and YM11, R-T32, Y-T67 for Kharif season. For superior cross combinations Y-M11 x Y-N10, Y-Ma5 x Y-N10, Y-Ma5 x Y-M6 for Rabi and Y-M11 x Y-N10, Y-Ma5 x Y-N10, Y-Ma5 x Y-S9 for Kharif, were identified based on the significant sca effect for grain yield and related traits. Heterosis was observed over mid parent and better parent for all the crosses studied. For commercial heterosis studies, identified the best top five hybrids for Rabi (H-1, H-2, H-12, H-16, H-35), for Kharif (H 1, H- 3, H-11, H-12, H-13) and two hybrids (H-1 and H-12) for both the season based on the significance of standard heterosis over the checks. Parents Y- M34, Y- M11 were identified as members of divergent subgroups viz. Populations I and II respectively with Y- M11 identified as a member of sub population POP-M9 while parents Y- M2, Y- T67 belonged to the admixture sub group Population III validating our results that these lines belonged to a primary germplasm source sufficiently diverse to be used for selection of potential parents for effective exploitation of heterosis.
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    Early generation MAS for selecting transgressive segregants carrying Pi9, PSTOL1 and yield related genes in elite X elite crosses of rice
    (2022-09) Magudeeswari P.; Rai, Mayank
    In order to enhance rice productivity under acidic soils of North Eastern Hill Region of India, breeding and selection for blast resistance and low P tolerance is most important along with yield component traits. Phenotypic selection in early segregating generations is not considered to be effective due to low to moderate heritability for most of the agronomic traits. However, use of allele specific DNA markers may enhance selection efficiency and heritability, thereby leading to higher genetic gain in a breeding programme. To test this hypothesis, 21 biparental populations developed from 13 parents were subjected to a combination of phenotypic selection along with MAS for PSTOL1 (phosphorus starvation tolerance), Pi9 (a major blast resistance genes), SPIKE (increased spikelet number) and Gn1a (increased grain number). Parental polymorphism survey for allele specific markers while SCM2 was fixed in all parents, DEP1 and OsSPL14 were completely absent. The segregating populations were subjected to early generation (F2) marker-assisted selection for Pi9 (ULRC66, ULRC67) and PSTOL1 (ULRC69) during the offseason and the remaining crosses were subjected to MAS for the abovementioned genes on phenotypically selected lines (kharif 2020). The MAS for PSTOL1 gene on phenotypically selected lines of eight segregating populations (ULRC52, ULRC56, ULRC57, ULRC69, ULRC70, ULRC72, ULRC73, ULRC77) was carried out and the results showed the presence of PSTOL1 significantly increased the tiller number at 60 days in all crosses and grain yield in ULRC56. Further, the segregating lines were evaluated for low phosphorous (P) tolerance under soil micro plot with normal (P+) and stress (P-) conditions. Analysis of variance (ANOVA) revealed the lines were significantly different for all traits and the interaction was found significant for tiller number at 45 days (TN45), spikelets per plant (SPP), filled grains per plant (FGPP), and plant height (PH). Shoot Phosphorus Use Efficiency (PUE) and P Efficiency Ratio (PER) were significantly correlated with biomass and grain yield under stress (minus P) conditions, suggesting that selection for PUE and PER may increase grain yield under low soil P conditions. Simultaneously, to find tolerant genotypes under stress conditions, eight stress tolerance indices (STI, GMP, TOL, SSI, YR, YI, PYR, YSI) were calculated and the data were subjected to PCA and unrooted cluster analysis. The results of PCA showed STI and GMP had positively contributed to PC1, and it revealed STI and GMP can be better indices to discriminate the tolerant and susceptible genotypes. Biplot and unrooted cluster tree clearly showed two groups, in which ULRC52-5, ULRC62-1, ULRC62-5 and ULRC62-SSD-5 were found more stable under both low P and normal conditions. MAS for Pi9 was carried out on four F2 populations (ULRC64, ULRC65, ULRC66, ULRC67) and evaluated for leaf blast disease under natural field conditions (kharif 2020 and kharif 2021) and artificial inoculated conditions. The results clearly showed that Pi9 (+ve) plants had recorded a low blast score compared to Pi9 (-ve) plants. From the Pi9 segregating populations, eleven lines carrying Pi9 at a homozygous state with high grain yield per plant were phenotypically selected and they can be used as a donor for Pi9 in future breeding programme. MAS for yield genes i.e., SPIKE and Gn1a was carried out on phenotypically selected lines of five and six segregating populations, respectively. The results showed the genes were significantly associated with high SPP, FGPP and GYPP in some, but not across all populations, suggesting interaction of these genes with genotypic “background” in determining the phenotype. ANOVA of segregating populations revealed the lines were significantly different for all the eleven traits in Kharif 2020 and the lines showed a significant difference for all traits except NP, SF, GYPP and BY in Kharif 2021. Response to selection was highest for ULRC52 (81.9%) followed by ULRC77 (54.2%), ULRC76 (25.2%) and ULRC68 (21%). The genetic gain for grain yield per plant was observed to be highest for ULRC76 (96%), followed by ULRC70 (25%), ULRC52 (13.61%) and ULRC62 (12.35%). Based on the evaluation of F4/F5 progenies the breeding value of parents was calculated and the results showed Maudamani reported a high breeding value for grain yield per plant (17.68) followed by CAUS103 (16.92), HPR2921(15.37) and CAUS107 (14.22). The parents with high breeding value can be used in a breeding programme to increase the genetic gain. The effectiveness of MAS and phenotypic selection were compared among the populations and it was found that mean of phenotypically selected lines was higher than the MAS selected lines. Genotypic selection alone for one or a few loci in early segregating generations may not lead to increased genetic gain compared to a combination of phenotypic and genotypic selection. Based on the presence of desirable alleles and superior performance under acidic soil ULRC52-SSD-2- 3-1, ULRC52-SSD-1-4 1, ULRC57-SSD-2-3-1, ULRC62-SSD-4-4-1 and ULRC62-SSD-5-6-1 lines were selected for further multilocational evaluation.
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    Evaluation of a set of rice (Oryza sativa L.) genotypes for grain yield and some important grain mineral content viz., Calcium (Ca), Magnesium (Mg), Iron (Fe) and Zinc (Zn).
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-10) Goswami, Shubhrata; Singh, K. Noren
    One of the main sources of dietary carbohydrates for billions of people worldwide, rice (Oryza sativa L.) is the main food for close to 3.5 billion people. Understanding the assessment of yield variability and its component aspects is crucial before executing any breeding programme for the genetic improvement of crop plants. To improve grain yield of rice in a specific condition, the contribution and relationship of its component characters viz., plant height, filled grains /panicle, days to 50% flowering and maturity, panicle length, 1000-grain weight and grain size are to be understood. Grain quality of rice plays a major role in the consumer acceptability and it is the second major breeding objective after yield. It also contributes in popularization of a variety as well as security in nutrition and health of those who consume it.43 genotypes were used in the current investigation to study the grain yield and the mineral content of the kernel. Four minerals, namely Ca, Mg, Fe, and Zn, as well as yield and its component characteristics, made up the total of 10 characters that were examined. Maximum variations were seen among the genotypes for important characters namely total number of grains/panicle (90.75 cm to 184.25 cm) followed by total number of filled grains/panicle (62.75 cm to 141.25 cm) and plant height (73.78cm to 150.31 cm).Heritability(broad sense)coupled with GAM was seen to be maximum in plant height (70.43%,29.37%). Heritability (broad sense) coupled with GAM was recorded to be maximum in Mg (97.27%, 82.34%) for mineral content. In correlation study, positive and significant correlation was seen between grain yield to total no. of tillers/plant, total no. of effective tillers/plant, total no. of grains/panicle and total no. of filled grains/panicle whereas it showed significant negative correlation with days to 80% maturity and days to 50% flowering. The results of the Path Analysis showed that that the total no. of effective tillers/plant (0.7592) had the maximum positive direct effects followed by total number filled grains/panicle (0.6633) to grain yield/plant. Maximum positive and indirect effects were recognized in no. of tillers/plant (0.7497) to grain yield/plant through no. of effective tillers/plant. For yield and its attributing characters, the intra cluster distance was observed maximum in the cluster V (70.621) containing 4 genotypes while the inter cluster distance was found to be maximum between the clusters IV and IX (911.174).Genotypes from the clusters I, II, IV and VII had higher mean values for grain yield and these can be used as a parent in hybridization programme. For mineral content, the intra cluster distance was observed maximum in the cluster V (18.972) containing 3 genotypes and the inter cluster distance was found to be maximum between the clusters IV and VI (274.390).Genotypes belonging to the clusters III and V were high in Ca, I and VI in Mg, IV and V for Fe and cluster VII for Zn. The study revealed that the genotypes NEH-2, NEH-12, CAU-R1, NEH-1, NEH-4, NEH-6, NEH-13, NEH-17 and CAU-R4 performed better for yield and attributing characters. Genotypes NEH-11, M-6T, NEH-1 and M-9 had better mineral content for Ca, Mg, Fe and Zn, respectively based on mean performance. However, the genotypes NEH-2, NEH-12, CAU-R1, NEH-4, NEH-13, M-11, and CAU-R4 were statistically at par for mineral content. Considering yield and attributing traits and mineral content together the genotypes CAU-R4, CAU-R1, NEH-1, NEH-2, NEH-4, NEH-12 and NEH-13 showed better performance and hence, these genotypes can be used for cultivation as well as can be utilized as a parent for further hybridization programmes.
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    ThesisItemOpen Access
    Evaluation of Citronella (cymbopogon winterianus jowitt.) genotypes for their oil yield and essential oil content under Meghalaya conditions.
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-10) Mallikarjun, P. K.; Singh, K. Noren
    Cymbopogon winterianus Jowitt. is a perennial aromatic and industrially valued crop belonging to the Poaceae family, which yields essential oil on distillation process. However, Citronella is extensively influenced by various environmental factors. Therefore, the present investigation was undertaken to evaluate the Genotype x Environment Interaction (GEI) and to select better performing genotypes having higher oil yield and other potential qualities from seven Citronella genotypes over four seasons by using Additive Main Effects and Multiplicative Interaction (AMMI) model and GGE biplot methods of analysis. The outcome of AMMI ANOVA can be studied using principal component analysis (PC1) which represented 69.79 % for plant height, 76.31 % for number of leaves per clump, 73.61 % for fresh biomass yield per plot and 61.74 % for essential oil yield of GEI sum of squares percentage. High oil yielding and widely stable genotypes were identified in having almost similar results for AMMI model and GGE biplot analysis. The genotypes Bio-13 and Mandakini were registered as high oil yielding and stable for essential oil yield, whereas JC-4 had higher fresh biomass yield and showed better adaptability for most of the traits. The consistent performance of these genotypes across all the seasons is due to their ability to tolerate wide environmental conditions. The Gas Chromatograph coupled with Mass Spectrometry (GC-MS) results revealed that the genotypes Jalapallavi, JC-2 and JC-4 were desirable for major essential oil constituents as they had high Citronellal, citronellol and geraniol percent respectively. Among the four seasons, Pre-kharif, 2019 (S2) was found to be the better season for most of the traits studied and Rabi, 2019-2020 (S4) was desirable from oil quality point of view as it was observed with higher percent concentration of chemical constituents except Citronellal. The molecular characterization of Citronella genotypes with SSR markers produced a total number of 57 alleles. The highest PIC value of 0.69 was recorded for CM007 and lowest value of 0.22 was recorded for CM4142 with an average value of 0.48. The highest similarity was found between the genotypes JC-1, JC-2 and JC-4, while the least similarity was found between genotypes Mandakini and JC-2 as well as between genotypes Bio-13 and JC-1. Therefore, these genotypes can be feasibly utilized in future developmental breeding programmes. This is the first study to describe on the stability of seven genotypes of Citronella for their economical traits under the agro-climatic conditions of Meghalaya.
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    ThesisItemOpen Access
    Evaluation of lentil (Lens culinaris ssp. culinaris Medikus) germplasm under low input acidic soil conditions of North East India
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2018-10) Singh, Sapam Rajeshkumar; Khanna, V. K.
    Lentil (Lens culinaris ssp. culinaris Medikus) is a diploid (2n=2x=14) self-pollinating crop with a genome size of approximately 4 Gbp. In spite of being the most consumed pulse of the NER, lentil is cultivated sporadically on relatively poor soils and in harsh environments with a little or no fertilizer after rice crop. Therefore, there is a need of identifying lentil germplasms that is adapted to low input acidic soils to achieve remunerative productivity. Breeding for improvement of lines compatible to drought and acidic soil conditions would increase productivity of lentil in this area. The present study was conducted to evaluate genetic divergence, correlation and path analysis and identification of superior lentil lines under acidic and water deficit conditions. Correlation and path analysis showed highest correlation of pod yield with number of pods per plant followed by shoot weight, number of secondary branches, days to 50% flowering, number of primary branches, harvest index, days to maturity, plant height, root weight and 100 seed weight with pod yield indicating the importance of plant biomass accumulation under nutrient deficient acidic soil conditions. The genotypes from clusters II, III, V and VI may be crossed with genotypes of cluster IV, VII and VIII for creating wide spectrum of variability and improving the grain yield, One hundred and sixty four lentil lines were subjected for PCA analysis for the morphological data on 15 traits in order to visualize the spread of genotypes around the major Eigen vectors. From the PCA analysis, the present study identified traits of importance and suitable genotypes like IPL-324, IPL-325, IPL-322, IPL-220, LRIC-560812, LRIC-569608, LRIC-559871, LRIC-201700, SKUAL-2-96, PL-101, DL-10-01, DPL-62 and PL-04 that can be used as varieties for upland acidic soils. The present study identified traits of importance and suitable genotypes like IPL-325, LRIC560812 and PL-04 that can be used directly as varieties for upland acidic soils, or can be crossed with diverse genotypes for breeding high yielding and suitable genotypes for such nutrient deficit, marginal and low pH soil conditions. From the stability analysis of the three environments genotypes IPL-322, IPL-325, IPL-220, IPL-324, LRIC-560812, LRIC-569608, LRIC-559871, LRIC-201700, SKUAL-2-96, PL-101, DL-10-01, DPL-62 and PL-04 recorded significantly higher mean with bi = 1 and S2di = 0 for pod yield, number of pods per plant, root weight and plant height indicating that these genotypes are suitable for growing in all the three environments. From the evaluation of 26 selected lines with 4 checks under acidic and water deficit conditions, lines DPL-62, IPL-220 were better performer than others and lines LRIC-560335 and L-4581 were worst performers. These lines along with a check line PL-8 were evaluated for root traits and P-uptake. The results of this study suggest that the variation in root morphology of the five varieties is pronounced, without the variation in the ability to induce chemical (rhizosphere pH) and biochemical (Aptase) change in the rhizosphere environment through root exudation
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    ThesisItemOpen Access
    Evaluation of Linseed (Linum usitatissimum) genotypes and their F1 hybrids under acidic upland conditions of Meghalaya
    (College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-08) Bezil M.; Rai, Mayank
    Linseed is the rabi crop cultivated for oilseed rich in omega -3 fatty acid and lustrous fibre. There is a potential for linseed cultivation in North Eastern Hill Region (NEHR) of India due to favourable climatic conditions. However, predominantly acidic soils in the region lead to phosphorus (P) deficiency and aluminium (Al) toxicity in upland conditions, which cause low crop productivity. Therefore, the study evaluated linseed genotypes under acidic upland field conditions for yield contributing traits. Evaluation of 35 genotypes across two seasons revealed significant variations among genotypes for all the traits except root length. Seasonal interactions were significant for all the traits. Phenotypic coefficient of variation was high for plant weight and yield per plant. Heritability was found to be high for test weight, followed by plant height. Yield was positively correlated with secondary branches, inflorescence length, number of capsules per plant, plant weight, days to 50% flowering and maturity. Path analysis showed that plant biomass and harvest index contribute the highest direct effect on yield. Based on GEI biplot, LMS-2015-14 was the most stable genotype. Clustering analysis elucidated that NL356 was the most divergent genotype forming the separate cluster. Comparative evaluation of these lines in soil microplot under P deficient and P deficient conditions identified LMS-2015-11 and BAU-15-03 as best lines with respect to P deficiency tolerance and yield. From the first season field experiment, five contrasting genotypes were identified to study their response to P deficiency and Al toxicity under hydroponics and sand culture. LMS-2015-11 was the tolerant genotype under both the stress condition. T397 was the susceptible genotype under Al3+ toxicity and SLS115 was the susceptible genotype under low P condition. In silico analysis was performed to find putative linseed orthologs, which showed 40% identity with maize and 45% identity with B. oleraceae. Selected five parents were crossed in diallele fashion to generate F1 hybrids, which were evaluated in second season along with 35 genotypes. Diallele cross analysis showed that variance due to GCA was significant for all traits except number of secondary branches, root length, number capsules per plant, plant weight, yield per plant and variance due to specific combining ability was significant for all the traits except number of primary branches and secondary branches. Low GCA/SCA ratio indicated predominant non- additive gene action for all traits. GCA effects were significant for test weight and days to 50% maturity. RLC 163 X SLS 115 (C1) and its reciprocal cross (C5) had high SCA effects for yield, indicating that RLC 163 (P1) and SLS 115 (P2) were the better combination to increase the yield. The genotypes and crosses identified will lead to better understanding of acidic condition response in linseed and development of breeding material suitable for acidic soils of NEHR.
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    Evaluation of rice (Oryza sativa L.) genotypes of North Eastern Hill Region (NEHR) for traits associated with anaerobic germination.
    (College of Post Graduate Studies in Agricultural Sciences, Central Agricultural Univerity, Imphal, 2022-10) Afeefa C. H.; Laloo, Bingiala
    Direct seeding is recently becoming increasingly popular among rice producers because of its ease of cultivation, economic benefits, early crop maturity, and greater yield. However, around one-third of all rice produced globally is grown in flood-prone locations, making flooding the third biggest source of stress that impedes rice production. Anaerobic germination (AG) which refers to a seed's innate ability to germinate under oxygen deficiency by acquiring the necessary energy through anaerobic respiration is a crucial characteristic for enhancing direst seeded rice. Reports of high yielding varieties tolerant to anaerobic germination are few, hence it is important to evaluate the rice genetic diversity to develop variety with these characteristics. It would also enable flooding the field during the earliest stages of germination as a successful weed control technique. In the present study, a set of 60 rice genotypes, which were collected from different parts of the North Eastern Hill Region was screened for various traits associated with anaerobic germination. A preliminary nursery evaluation of morphological traits showed significant variation among the set of genotypes for all the traits (speed of germination, germination percentage, visual scoring of seedling vigour, shoot length, thickness of stem, number of leaves, leaf area index). Anaerobic experiment was designed to screen the genotypes under the anaerobic condition with 8 cm of submergence as well as a controlled set-up. The observations were recorded till 21 days after sowing. All the morpho-physiological parameters (seedling vigour index, germination percentage, speed of germination, survival percentage, shoot length, root length, fresh weight, dry weight, number of leaves) showed high significant genotype x treatment (anaerobic and control conditions) interaction suggesting that there is a significant variance in the genotypes with respect to submergence. The correlation study did not reveal significant correlation between traits under nursery and anaerobic condition except for shoot length (r=0.43) and number of leaves (r=0.32). Amongst the traits studied under anaerobic treatment, seedling vigour index-II showed significant and positive correlation with 11 other anaerobic traits namely seedling vigour index-I (r= 0.94), speed of germination (r= 0.88), survival percentage (r=0.84), germination percentage (r= 0.79), relative germination percentage (r= 0.46), number of leaves (r= 0.43), fresh weight (r= 0.38), dry weight (r= 0.34), root length (r=0.33), plant portion above water (r = 0.32) and shoot length (r = 0.31). PCA registered a cumulative variation of 63.3 % from the first two PCs, with PC1 accounting for 42.9% and PC2 accounting for 20.4 % of the total variation. Based on PCA, contrasting genotypes were identified, where four were identified as tolerant (Lakang Baso, Sahbhangi Dhan, CAUS 107 and CAUS 123) and the rest as susceptible (BLM, Chakhao Poireiton, Phourel and Mailung). The alpha amylase and peroxidase enzyme activity in the selected genotypes showed significant and considerable variation among genotypes. The tolerant genotypes showed higher alpha amylase activity with an average of 228.51 μmol/min as compared to the susceptible ones (77.15 μmol/min). The correlation study revealed that there is a positive correlation between alpha amylase activity and all the 13 anaerobic traits, in which, survival percentage (r= 0.84), number of leaves (r= 0.93), speed of germination (r= 0.76), germination percentage (r= 0.77), relative germination percentage (r= 0.72) and anaerobic germination index (r= 0.73) showed a significant and positive correlation. However, there was no significant correlation between peroxidise activity and any of the nursery traits or anaerobic traits. The traits such as seedling vigour index, survival percentage, germination percentage, shoot length and alpha amylase activity were amongst the promising indicators for tolerance to germination under anaerobic conditions. The identified contrasting genotypes in the study could be a valuable resource for future breeding programs.