ThesisItem Open AccessCHARACTERIZATION OF HYBRIDS AND THEIR PARENTAL LINES IN RICE (Oryza sativa L.)(AAU, Jorhat, 2018) YOGEESH, S C; Sarma, AkashiFor successful adoption of hybrid rice technology, assessment and maintenance of the genetic purity of hybrids is very crucial for quality control components in hybrid seed production. The present investigation was undertaken with an objective to distinguish the locally bred rice hybrid IR79156A/Swarna and its parental lines using morphological, chemical and molecular markers for genetic purity testing. Morphological characterization of IR79156A (CMS line), Swarna (restorer line) and their hybrid combination IR79156A/Swarna was performed using forty four qualitative and fourteen quantitative traits during Sali 2017. Among forty four qualitative traits six characters viz. male sterility, flag leaf attitude of blade (late observation), panicle secondary branching, decorticated grain shape, gelatinization temperature and decorticated grain aroma were useful in distinguishing the parental lines and hybrid and hence these traits can be used for rapid identification of hybrid and its parental lines. The analysis of variance revealed significant differences for all the quantitative characters among the hybrid IR79156A/Swarna and its parental lines. Out of four rapid chemical tests only phenol test and modified phenol test with CuSO4 were able to differentiate hybrid from its parental lines. NaOH and KOH test were not useful in differentiating the hybrid and its parental lines. A total of ten SSR markers were employed for fingerprinting of the rice hybrid IR79156A/Swarna and its parental lines. Out of 10 SSR markers, four SSR markers viz. RM206, RM216, RM234 and RM263 were identified and successfully employed for molecular characterization of the parental lines and hybrid. SSR marker RM234 was identified as a highly informative marker. The SSR marker RM234 could be effectively utilized for assessment of hybrid purity of rice hybrid IR79156A/Swarna. Thus, molecular markers along with few morphological traits and rapid chemical tests (standard phenol and modified phenol test) were most useful for identification of parental lines and hybrid IR79156A/Swarna and hence could be successfully employed for genetic purity testing. ThesisItem Open AccessEFFECT OF DIFFERENT THRESHING METHODS ON SEED QUALITY OF PADDY(AAU, Jorhat, 2018) GOGOI, KRISHNALI; Borah, AbhijitThreshing is an important aspect for paddy seed processing. Proper threshing limits the rate of seed deterioration during long term storage. Improper threshing can also cause high threshing and scattering losses. So, the present study was conducted to identify the effect of different threshing methods on seed quality of paddy before storage and during the nine months of storage period. The study was conducted with rice variety ‘Soi lahi’, which was collected from farmers’ field, Sibsagar followed by threshing in different threshing methods (5 treatments) viz., Bullock treading, Power tiller treading, Japanese paddy thresher, Modified Japanese paddy thresher, Manual threshing. Seed quality testing was done in four replications for each treatment before storage. After threshing, the samples were stored in high density poly ethylene (HDPE) interwoven bags for 9 months and the observations were taken bimonthly. The observations were recorded on the quality parameters, viz, moisture content, viability, germination percentage, seed vigour index-I and II, seedling length, field emergence percentage and pathogenic infestation before and during the entire storage period. The data recorded for each parameter were subjected to analysis of variance (ANOVA). All the seed quality parameters were found to be highest before storage when seeds were threshed manually. Considering threshing along with storage, highest germination percentage was also observed in samples threshed manually and found significantly different from all other threshing methods under study, except modified Japanese paddy thresher. The seed viability, vigour, seedling length and field emergence were found to be highest in manual threshing during the entire storage period as well. Among the other methods, the seed quality parameters were found to be highest in samples threshed by modified Japanese paddy thresher during subsequent storage periods. This was due to the rubber padding on the canopy where the threshed paddy seed strikes which in turn reduces the shock of impact resulting better quality seed parameters after threshing. In view of inherent disadvantages of labour intensive manual threshing and small output capacity, it is not suitable for large scale seed production. From the present study it could be inferred that among the other threshing methods studied, modified Japanese paddy thresher was found to be the best method of threshing for quality paddy seed production and can be advocated for large scale seed production. ThesisItem Open AccessSEED HEALTH STATUS OF FARMERS’ PADDY SEEDS OF JORHAT DISTRICT OF ASSAM(AAU, Jorhat, 2018) Borkakati, Hemanta; Medhi, TIndia is major rice (Oryza sativa L.) producing country and stands second with an annual production of 155 million tons (Anon, 2011). Storage of rice seeds is an important practice in order to secure the food as well as to ensure the availability of healthy seeds for the next planting season. The purpose of proper seed storage is to retain its viability and vigour and should keep it free from disease and pests. In the present investigation, health status of farmers’ saved seeds of various paddy varieties of Jorhat district of Assam was evaluated. Fifty samples of 19 varieties of rice seeds (250 g each), stored in two different storage structures viz. Duli and Jute bags were collected from fifty (50) farmers of different villages of Jorhat district and 33 samples from Regional Agricultural Research Station (RARS), Assam Agricultural University (AAU) Titabar, Jorhat, at 0 and 180 days of storage of winter rice. Seed qualities parameters viz., moisture content increased in the seeds stored in all the villages after 180 days of storage irrespective of the storage structures. It was significantly the lowest in the seeds collected from Charigaon village both at 0 (13.34 percent) and 180 (14.63 percent) days of storage. Seeds samples collected from Jankhona village showed the highest moisture content but it was statistically at par with Mishing Gaon and Jamuguri after 180 days of storage.Germination percentage declined in the stored seeds after 180 days in all the locations. At 0 day of storage, seeds from only two villages (80.67 percent and 80.20 percent in Charigaon and Jamuguri respectively) showed mean germination percentage above Indian Minimum Seed Certification Standards (IMSCS) level. After 180 days, seeds from none of the villages showed germination above IMSCS level. Significant difference was observed among the notified and farmers’ varieties in terms of germination percentage. Germination ranged from 80.50 to 92.00 percent in the notified varieties whereas in farmers’ varieties, it ranged from 32.76 to 74.40 percent at 0 day of storage. Seedling vigour was higher in seeds collected from Charigaon both at 0 (1299.34) and 180 days (1228.82) of storage however it was at par with that of Jamuguri (1225.19) and Shyam Gaon (1208.28) at 0 day and with that of Mishing Gaon (1191.34) and Shyam Gaon (1110.78) after 180 days of storage. Similarly, speed of germination was highest in seeds from Charigaon both at 0 (13.55) and at 180 days (12.14) of storage. The mean germination time was low both at 0 (5.83) and 180 days (6.83) of storage. Similarly, mean daily germination, peak value and germination value was recorded maximum at Charigaon at 0 and 180 days of storage. Seven fungal species viz. Aspergillus spp., Fusarium spp., Curvularia spp., Penicillium spp., Rhizopus spp., and Bipolaris spp. were found to be associated with the seeds collected from the five villages sand RARS, Titabar in different per cent frequencies, Aspergillus spp. being the predominant one. However, Alternaria spp. was absent in the farmers’ saved seeds whereas Rhizopus spp. was absent in seeds collected from RARS. The seed samples from Jankhona were highly infected by seed borne mycoflora (27.14 per cent and 64.29 per cent at 0 and 180 days of storage respectively). The lowest seed infection was recorded in the seeds collected from Charigaon (11.43 per cent and 37.13 per cent at 0 and 180 days of storage respectively). Storage structures did not have significant effect in any of the parameters studied. The present findings revealed that the seeds collected from the five villages were inferior in terms of seed quality and seed health. Awareness among and training of farmers regarding scientific methods of production and storages for healthy, disease free quality seed is a prerequisite to sustain the food security. ThesisItem Open AccessGENETIC VARIABILITY STUDIES IN POTATO (Solanum tuberosum L.)(AAU, Jorhat, 2018) Singha, Lopamudra; Ullah, ZafarThe experiment was taken up to elicit the information on magnitude of genetic variability, heritability and to predict the gains realized through selection, character association and divergence for the yield and its attributing characters in potato (Solanum tuberosum L.) genotypes. Thirty eight genotypes of potato were evaluated in RBD with two replications during Rabi season of 2016-17 and 2017-18 at ICR farm, Assam Agricultural University, Jorhat. The estimates of analysis of variance were significant for all the parameters. The analysis of genetic variance revealed that there was significant genetic variability in the experimental materials. Among all the genotypes studied, genotype CP 1994 showed highest tuber yield, marketable tuber yield and number of branches and found suitable to further crop improvement programme. The genotypes CP 2008 and CP 1931 were also found to be elite for different characters. Among the characters studied, high PCV and GCV were observed for characters like total tuber yield, LAI and marketable tuber yield indicating high variability available in the germplasm for these characters for further improvement. A high heritability with high genetic advance was found for LAI, marketable tuber yield and total tuber yield which suggested that there may be presence of additive gene action and selection will be rewarding for improvement of such traits. Total tuber yield was strongly correlated with number of branches per plant, average tuber weight and marketable tuber yield both in genotypic and phenotypic levels suggesting the importance of these traits in selection for yield and can be identified as yield attributing characters for the genetic improvement of yield in potato. All the genotypes under study were grouped into seven different and diverse clusters; D2 values noted for different parameters indicated the presence of appreciable genetic diversity in the genotypes included in the investigation. Cluster I had the maximum number of genotypes (16) followed by cluster II (11). Maximum inter-cluster distance was observed between cluster II and cluster VII which g comprised of more number of genotypes while the intra-cluster distance maximum in cluster VII. Inter-cluster distance was higher than intra-cluster distance indicating existence of sufficient genetic diversity among the genotypes of different clusters. Genetic diversity study suggested that genotypes namely CP 1994, K. Khyati, CP 1987 and CP 1931 possessed high per se performance. Thus, these genotypes may be included in hybridization programme for getting superior hybrids and development of high yielding varieties. ThesisItem Open AccessSTUDY OF HETEROSIS AND GENE ACTION IN A DIALLEL CROSS OF GRASS PEA (Lathyrus sativus L.) GENOTYPES(AAU, Jorhat, 2018) Lyngdoh, Andrean Allwin; Bora Neog, SeujiGrass pea (Lathyrussativus L.) is a dual purpose annual legume grown for its seeds for human consumption and fodder for livestock feeding. However, advancements in the development of grass pea varieties having high-quality and high forage yield are yet to be made. The present investigation was conducted to evaluate genotypes for high forage yield coupled with low ODAP content. Seven diverse parental lines of grass pea were crossed in a 7 × 7 diallel mating design excluding reciprocals. The twenty one F1 hybrids obtained were evaluated along with their parents in a Randomised Block Deign with 3 replications. Analysis of variance revealed significant differences among the parents and the F1’s for all the characters studied. Phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability (H) and genetic advance (GA) were high forODAP content, green forage yield per plant, dry matter yield per plant, secondary branches per plant, plant height and leaves per plant. The studies on combining ability indicated the predominance of dominance variance for most of the characters studied except for days to 50% flowering and leaves per plant. The parentPrateek was the best general combiner for both green forage yield per plant and for low ODAP content. Based on SCA effect and per se performance the crossNirmal×Prateekwas the best specific combiner for green forage yield, while the crossPrateek× JCL-3 was the best specific combinerfor low ODAP content. Significant heterosis was observed in desirable direction for most of the traits. From the estimation of heterosis over mid parent and better parent, the cross JCL-2 × JCL-3 was the best heterotic cross for green forage yield per plant while the crosses Prateek× JCL-3 was recognized as best heterotic cross for ODAP content. The correlation studies highlighted the importance of plant height, leaves per plant, primary branches per plant, secondary branches per plant, nodes per plant and dry matter yield per plant which were significantly associated with green forage yield. ThesisItem Open AccessMORPHOLOGICAL AND MOLECULAR CHARACTERIZATION IN BRINJAL(AAU, Jorhat, 2018) Lalhruaitluangi, B; Bora, G CThe present study was conducted to characterize 31 brinjal (Solanum melongena L.) genotypes at Morphological and molecular levels. A total of 11 quantitative traits were utilized to analyze various genetic variability assessments. Highest estimates of PCV (32.32%) and GCV (31.78%) were observed for yield per plant. High heritability and high genetic advance for yield per plant, fruit length and plant height revealed preponderance of additive gene action. Fruit yield per plant showed highly significant and positive correlation with days to 75% fruit set (0.25) followed by plant height (0.20) at genotypic level. Mahalanobis D2 statistic grouped 31 brinjal lines into six clusters with the maximum genotypes in cluster VI and lowest in cluster III. The highest intra-cluster D2 (308.91) and inter-cluster D2 (212.42) were unveiled in cluster I and between cluster II and V. The highest mean values for Days to 75% fruit set were displayed in Cluster IV. The molecular characterization using 20 SSR markers revealed polymorphism in 12 markers. Among 12 polymorphic SSR loci, the highest number of alleles per marker was recorded in Emf21I04, EmboD19 and Emd05012 (3 alleles). Jaccard’s similarity coefficient showed no true duplicates and it ranged from 0.160 (between ML-1 and B-4) and 0.933 (between B-17 and B-10), indicating sufficient genetic variability among the cultivars under study. Presence of unique marker allele was specifically observed in B-19 and ML-1 for emh05B02 and emf11N23 respectively. Cluster analysis separated the genotypes into four clusters i.e. cluster I, II, III and IV. Cluster III is largest with five genotypes, while cluster I and IV have only two genotypes. Sub-grouping / bifurcation of groups was possible to detect further lineage for what actually obtained using morphological data. This study provided useful information about trait variability and it may be expected to open up opportunities to generate catchy capsule in characterizing the cultivars. ThesisItem Open AccessEVALUATION OF S1 LINES OF MAIZE (Zea mays L.) FOR FODDER RELATED ATTRIBUTES(AAU, Jorhat, 2018) Teron, Rangbamon; Neog, S. B.Maize (Zea mays L.) is an important cereal crop and ranks third in India’s production. It can be grown as dual crop for grain as well as for fodder. It is an important cereal fodder and increasingly use as an animal feed and fodder crop for both green forage and silage. Forage maize is quick growing, succulent, sweet, palatable, high yielding, nutritious and free from toxicants and can be safely fed to animals. Green fodder provides adequate energy and proteins for growth of animals and milk production. Maize silage is primarily an energy feed and its nutritional value is a function of digestibility. African tall and J-1006 showed the most promising variety for forage yield and till date no other variety had developed that can overcome this promising variety. The present investigation was conducted during rabi 2016-17 (selfing) and rabi 2017-18 (evaluation) at Instructional-Cum-Research Farm of Assam Agricultural University, Jorhat to evaluate the genetic parameters and yield performance of twenty-five forage maize (Zea mays L.) germplasms. Analysis of variance revealed significant variation among the genotypes for all the characters except leaves per plant, leaf-stem ratio, crude protein content and dry matter percentage. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) was recorded highest for dry matter yield followed by per day productivity of dry matter yield. Dry matter yield, per day productivity of dry matter yield and green forage yield, green forage yield per plant, leaf area, ears per plant and leaf breadth having high genotypic coefficient of variation, heritability in broad sense and genetic advance as per cent mean indicates preponderance of additive gene action. Correlation studies revealed that green forage yield had significant positive correlation with days to 50 per cent flowering, plant height, stem diameter, leaves per plant, leaf breadth, leaf-stem ratio, leaf area, ear height, ears per plant, total carbohydrate content, dry matter percentage, dry matter yield and per day productivity of dry matter yield at genotypic level. Hence, these could be treated as prime characters for increasing forage yield. Path analysis at genotypic level revealed that leaf area had the maximum direct effect on green forage yield followed by total carbohydrate content, dry matter yield and ear height exhibited high negative direct effect respectively. Path analysis at phenotypic level revealed that dry matter yield had the maximum direct effect on green forage yield followed by per day productivity of dry matter yield and per day productivity of green forage yield exhibited highest negative direct effect respectively. JCM-13-6 was found to be highest plant height among the local germplasm. JCM-13-18 had more total carbohydrate content and dry matter yield. ThesisItem Open AccessVariation in morpho-agronomic traits of lowland rice (Oryza sativa L.) genotypes of Assam in response to phosphorus fertilization(AAU, Jorhat, 2018) Das, Priyanka; Sarma, DebojitThe present investigation was conducted with twenty-four genotypes (sub-plot) in two phosphorus doses (main plot) in a split-plot design with three replications during the Sali season of 2017 at ICR farm, AAU. The ANOVA for 15 characters studied revealed significant variation between the phosphorus doses (0 and 20 kg P2O5 ha-1) for days to heading and 50% flowering, root length and root volume per hill. A highly significant variation among the genotypes was observed for all the 15 characters. The genotype and phosphorus interaction effects were significant for panicle length, filled grains/panicle, chaffs/panicle, spikelet fertility, 1000-grain weights, root length, root dry weight and root volume. A significant advance in days to heading and 50% flowering along with an enhancement in root length and volume was registered for 20 kg P2O5 ha-1. Based on CD (5%), the superior genotypes with desirable means were Suagmoni for days to heading and 50% flowering, panicle length, chaff per panicle, spikelet fertility, 1000-grain weights and root length; Pankaj for grain yield/hill, harvest index and root dry weight; Dhirendra for days to heading and plant height; Herapoa for filled grains/panicle and shoot dry weight; Local Joha for effective tillers/hill and Gitesh for root volume. Amongst the 24 genotypes, only 7 genotypes namely Herapoa, Gondhi Biroin, Pankaj, Prabhat Sali, Gheu Bora, Betguti-2 and Tulsi Bora were categorized as high performing on the basis of total scores worked out of all the characters. A significant increase at applied phosphorus dose was observed for panicle length in Suagmoni; spikelet fertility in Herapoa, Kokua Bora and Joha Bora; 1000-grain weights in Tulsi Bora, Joha Bora and Aghoni Bora; root length in Suagmoni, Black rice, Kon Joha-M and Harinarayan; root dry weight in Gitesh, Joha Bora, Kon Joha-M and Harinarayan; root length in Gitesh, Joha Bora, Kon Joha-M and Harinarayan and root volume in Suagmoni, Gitesh, Prabhat Sali, Kokua Bora, Tulsi Bora, Aghoni Bora, Kali Jeera, Jowalpool, Kunkuni Joha, Harinarayan and Kon Joha-1 whereas a significant decline in number of chaffs was observed in Joha Bora and Kokua Bora. A higher magnitude of PCV than GCV for grain yield and effective tillers indicated a greater environmental influence on these characters. High estimates of GCV and PCV along with moderate to high heritability and high GA for chaffs/panicle, 1000-grain weights, grain yield, shoot and root dry weights indicated the importance of additive gene actions in the inheritance of these characters. Among the 3 diverse variety groups, glutinous genotypes contained the highest number of high yielding and phosphorus efficient genotypes followed by normal Sali while the aromatic had only intermediate types. The genotype Herapoa proved to be highly phosphorus efficient based on mean grain yield and grain yield efficiency index (GYEI). This study proved the presence of P-efficient genotypes among the rice landraces of Assam to be used in breeding for low input or organic farming. ThesisItem Open AccessGENETIC VARIATION FOR ADAPTIVE TRAITS IN EARLY MATURING PIGEON PEA (Cajanus cajan L.) GENOTYPES(AAU, Jorhat, 2018) Borah, Namita; Sarma, AkashiPigeon pea is an important legume crop of India. It is an important source of dietary based protein. It complements to cereal based diet of India. With 21-25% protein content it acts as a source protein for vegetarians. The present investigation consisted of twenty-five genotypes among which twenty-three were received from ICRISAT, Hyderabad and two from BNCA, AAU.The experiment was carried out during kharif season 2017-18 using randomized block design (RBD) with three replications at ICR farm, Assam Agricultural University. Among the twenty-five genotypes four genotypes namely ICP 11737, ICP 8509, ICP 6974 and ICP 7110 did not germinate therefore observations were recorded only for twenty-one genotypes. Observations were recorded for fourteen quantitative traits/characters. All the characters studied exhibited significant variability among them. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) was recorded highestforhundred seed weight followed by pods per plant, clusters per plant, harvest index, branches per plant and seed yield per plant.High heritability with moderate genetic advance was recorded for days to 50% flowering and low heritability coupled with low genetic advance was recorded for seeds per pod and low heritability coupled with moderate genetic advance was recorded for branches per plant. Duncan’s multiple range test for days to maturity revealed that there was significant differences between the groups.High significance difference was shown by ICP 14927 (89 days) which was the earliest maturing genotype and ICP 6973 (134 days) which was late maturing genotype. Correlation studies revealed significant positive association of seed yield per plant with plant height, pods per plant, pod length and harvest index both at phenotypic and genotypic level. Path analysis revealed that the character pods per plant has the highest positive direct effect on seed yield per plant followed by days to 50% flowering, pod length, plant height, branches per plant and harvest index. At genotypic level, branches per plant, clusters per plant and seeds per pod had negative direct effect on seed yield and days to first flowering (10.865) exhibited the maximum positive direct effect on seed yield per plant. The mean performance of the genotypes for yield and yield attributing traits revealed that ICP 15011, ICP 14927, ICP 15312, ICP 11610, ICP 11599, ICP 10920, ICP 11639 are few early maturing genotypes which exhibited good performance for most of the important quantitative traits which could be used in the development of high yielding, early maturing, short statured varieties.