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Open Access
Identification of superior parents and crosses using combining ability analysis for improvement of yellow sarson (B. rapa var. yellow sarson)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Chaturvedi, Sameer; Pant, Usha
The present investigation entitled was conducted with the objective to estimate selection and variability parameters, to estimate the combining ability variances and their effects and toestimation of level of heterosis for different quantitative traits. The present study was conducted at NEB, CRC during rabi season 2014-15 and 2015-16. The experimental materials for the present investigation consisted of 40 F1’s, 10 lines as female and 4 testers as males. Data were subjected to appropriate statistical methods. Awide range of usable variability was present in the experimental material with respect to various characters. The magnitude of phenotypic coefficients of variability (PCV) was observed greater than genotypic coefficient of variability (GCV) and environmental coefficient of variability (ECV) for all the characters under studied. High estimates of heritability were observed in most of trait. Highest heritability was observed in seed/siliqua (94.30%), followed by seed yield per plant (90.61%) and number of primary branches/plant (84.59%). The traits having high heritability with high genetic advance were observed in seed yield/plant (32.34%), seed/siliqua (29.12%) and number of primary branches/plant (21.70%). The ANOVA showed that mean sum of squares due to treatments were highly significant.Parents as well as crosses were highly variable for all the traits. However, variance due to parents vs crosses for all the characters barring length main raceme and 1000-seed weight. Partitioning of variances due to crosses into lines, testers and line × tester revealed that variances due to lines were significant for all the characters except number of primary branches per plant and oil content while variances due to testers were significant for siliqua length, seeds per siliqua and test weight. Variances due to interaction were significant for all the characters.Combining ability analysis illustrated that the estimate of 𝜎2 sca was higher than 𝜎2 gcafor all the traits studied. The average degree of dominance was also in the range of over dominance for all the traits except siliqua length. Heritability in narrow sense (h2 n) was low for all the traits which further substantiated the prevalence of non-additive gene action in the expression of traits.Based on estimates of desirable GCA effects, B-9 was identified as good general combiner for days to maturity. For Plant height and siliqua density, Jhumka was the best parent to contribute in desirable direction. NDYS116, NDYS-128, NDYS-2018 and NDYS-132 were the best parent for length of main raceme, siliquae on main raceme and siliqua length respectively. For number of seeds per siliqua and seed yield per plant YS-166 was emerged as best parent with desirable significant effect. Jhumka × NDYS-113 (-3.63*) for days to maturity, NDYS-115 × Pusa Gold (- 15.79**) for plant height, NDYS-107×PPS-1 (7.32**) for length of main raceme, B-9×Pusa Gold (6.10**) for silquae on main raceme, NDYS-107 × PPS-1 (1.84**) for primary branches plant, NRCYS-05-02 × Pusa Gold (0.44*) for siliqua length, NRCYS-05-02 × Pusa Gold (4.98**) for seeds per siliqua, NDYS-128 × PPS-1 (2.02**) for seed yield per plant, NDYS-107 × NRCYS-05-01 (0.42**) for test weight and YS-166 × NDYS-113 (2.12**) for oil content expressed highest SCA effects in desirable direction.The superior crosses identified based on their SCA effects for yield as well as oil content were having G × G, G × P, G×A, A×P or P × P GCA parents. These results indicate the operation of additive × additive, additive × dominance, dominance× dominance gene interactions for expression of these traits.The contribution of interaction was higher as compare to lines and testers for all the traits excluding days to maturity, length of main raceme, siliquae on main raceme, siliqua length, seeds per siliqua and 1000-seed weight.Regarding heterosis for days to maturity, NDYS-2018×NDYS-113 (12.21**) showed maximum better parent heterosis. Highest relative heterosis was noticed in NDYS-2018 × Pusa Gold (-11.62**) whereas, B-9 × PPS-1(- 8.65**) expressed maximum economic heterosis. NDYS-115 × Pusa Gold (-15.69**, -15.85**) possessed highest estimates of heterobeltiosis and mid parent heterosis while NDYS-2018×NRCYS-05-01 (-9.65**) was the best cross in respect of economic heterosis for plant height. For seed yield cross Jhumka × NDYS-113 (52.36**, 65.34**) showed maximum heterobeltiosis and relative heterosis while maximum economic heterosis was registered in NDYS-128 × PPS-1 (41.54**). In test weight maximum heterosis over better parent was found in NDYS-128 × NDYS-113 (24.47**) and highest estimates of relative and economic heterosis was possessed by NDYS-132 × NDYS-113 (25.18**, 22.29**) respectively. A single cross YS-166 × NDYS-113 (7.57**, 7.74**, 8.40**) showed maximum heterobeltiosis, relative heterosis and economic heterosis for oil content. From the present investigation involvement of non-additive genetic variance for most of the characters was reflected, so maintenance of heterozygosity or restoring it at the end of the breeding programme is suggested. Potential parents and crosses have been identified based on relevant multiple parameters. By utilizing these parents and cross combinations maximum gain can be achieved in yellow sarson by adopting most appropriate breeding strategies.
Open Access
Studies on seed invigoration and effect of silica nanoparticles (SiO2) on seed quality parameters of maize (Zea mays L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Chourasia, Vinay Kumar; Shukla, P.S.
Open Access
Combining ability analysis for yield and quality parameter in sugarcane (Saccharum sp. Complex)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-01) Pandey, Deepanker; Singh, S.P.
Sugarcane is a major crop of tropical and sub-tropical regions worldwide and belongs to the family Gramineae , tribe Andropogoneae, sub tribe Saccaharinineae, genus Saccharum. Sugarcane varieties are complex poly-ploids and their chromosome number varies from 2n = 100 to 120 or more. The yield and quality components in sugarcane are quantitative in nature and governed by poly genes, which are largely influenced by environmental factors. Therefore, it is essential to judge what proportion of observed variation of a particular character is heritable or due to environmental variation along with the transmissibility of the character. The knowledge of combining ability (ability of a genotype to transmit superior performance to its crosses) together with per se performance of the parents and hybrids, and heterotic response helps the breeders in selecting suitable parents and crosses for their use in a systematic breeding programme. Several techniques are available to elucidate the genetic makeup of the parents with respect to their ability to transmit characters of interest. Among those, the present study utilized Line × Tester and NC-I mating design to evaluate the genetic potential of parents based on the General Combining Ability estimates for different characters in Sugarcane. The crosses were attempted at National Hybridization Garden at Sugarcane Breeding Institute; Coimbatore Tamil Nadu for both Line × tester design and NCD-I mating and later on evaluation of progenies were carried out at the Sugarcane Breeding Experimental Block of Norman Borlaug Crop Research Centre, GBPUA&T, Pantnagar, U. S. Nagar, Uttarakhand during 2013-2017. The observations were recorded for eight morphological and five quality traits and analyzed through standard statistical procedures of the mating designs. General combining ability analysis from Line × Tester design revealed that Co Pant 99213 was a good general combiner for germination percent, number of tillers and number of millable canes, while Co Pant 94213 found good combiner for Brixpercent, pol value, sucrose percent and C.C.S. percent. Tester, Co Pant 97222 had good general combining ability for germination percent and number of tillers. Results of North Carolina Design Irevealed that Co 775 exhibited positive significant gca values for Cane Height, Pol value, Sucrose percent and C.C.S. Percent, which is sufficient to conclude that this is gooddonor for these traits. Highheritability accompanied by higher genetic advance under selection was found in case of Germination Percent, number of tiller, NMC(000/ha), and Pol value, reflecting predominance of additive genetic effect for these traits. These traits could be used as indices for selection under Sugarcane improvement programme. Results of heterosis analysis concluded with the identification of two best hybrids namely Co Pant 84212 × Co Pant 97222 and Co Pant 99213 × Co Pant 97222 which can be promoted through vegetative propagation for yield trials. As the F1 progenies in Sugarcane offers segregation and transgressive recombinant, the best clones with high sugar and early maturing sugarcane can be selected from the progenies of these crosses for identification of superior clones to develop improved sugarcane varieties.
Open Access
Early generation selection based on genetic parameters and molecular diversity in parental lines of soybean [Glycine max (L.) Merrill]
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-01) Bisht, Meenakshi; Singh, Kamendra
The present investigation was carried out with the objectives to study the efficiency of early generation selection, residual heterosis, transgressive segregation, inter-character association and their direct and indirect effects on yield and molecular marker analysis using seventeen different SSR primers for effective selection of genotypes and improvement of soybean. For field experiment, 36 genotypes of soybean comprising 14 crosses, 20 parents and two checks (PS 19 and SL 688) were evaluated in F2 generation using randomized block design with two replications in kharif 2015 and 14 crosses along with their 21 progenies (10 high value group, 10 low value group and 10 bulk) were evaluated in compact family block design with two replications in kharif 2016 at the Norman E Borlaug Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar. The Analysis of variance was found highly significant for all the characters undertaken in both the generations. The study on early generation selection with various genetic parameters revealed that characters days to 50% flowering, plant height, number of pods per plant and seed yield per plant exhibited positive and significant value for intergeneration correlation coefficient. The estimate of intergeneration regression coefficient revealed that days to 50% flowering, plant height and seed yield per plant were positive and significant. The number of pods per plant and seed yield per plant displayed significant and positive value for response to selection. High heritability coupled with high genetic advance was observed for seed yield per plant in both the generations. The value of realized heritability was found higher for days to 50% flowering, number of pods per plant and seed yield per plant. High performance of F3 bulk than F2 generation and F3 high group proved bulk method to be more effective than the pedigree method The per se performance of F2 generation for seed yield per plant was highest for three crosses, PS 1584 X JS 20-69 (20.7g), PS 1583 X JS 20-29 (20.08g) and PS 1225 X PS 1347 (19.58 g), for F3 high yielding group it was highest in PS 1584 X JS 20-69 (42.63g), PS 1583 X JS 20-29 (33.40g) and PS 1584 X JS 20-41 (29.79g), similarly the per se performance in F3 bulk was highest in PS 1584 X JS 20-69 (50.12g), JS 20-29 X JS 20-55 (39.76g) and JS 20-69 X JS 20-59 (35.63g). On overall basis, seed yield per plant was found to be effective for early generation selection. The study of nature and magnitude of residual heterosis revealed that PS 1584 X JS 20-41. PS 1583 X Bragg, PS 1584 X JS 20-69 and PS 1583 X JS 20-29 showed significant and positive residual heterosis over mid-parents. Over better parent, PS 1584 X JS 20-41 and PS 1583 X Bragg showed significant and positive residual heterosis over better parent, while PS 1584 X JS 20-69 showed positive and significant residual heterosis over both the checks, in F3 generation while none of the crosses showed significant residual heterosis in F2 generation. All the F2 crosses showed positive transgressive segregants for seed yield per plant but moderate frequency was observed. Highest positive transgressive segregant for seed yield per plant was recorded in the cross, PS 1042 X PS 1347. Occurrence of transgressive segregants in segregating generation is helpful for development of homozygous lines by continued selfing in crops like soybean. The present study revealed that in F2 and F3, dry matter weight per plant, plant height, number of primary branches per plant, number of pods per plant, number of seeds per pod and harvest index exhibited significant and positive correlation with seed yield per plant. The component characters which showed highest direct effect on seed yield per plant were harvest index and dry matter weight per plant in F2 generation and number of pods per plant in F3 generation indicating selection of these characters will bring direct improvement in seed yield The molecular diversity analysis of twenty two soybean genotypes revealed that the Jaccard’s similarity coefficient estimates varied from 0.29 (JS 20-59 and Pb1, JS 20-54 and Pb1, PS 1584 and PS 1347, JS 20-41 and PS 1347) to 0.82 (JS 97-52 and JS 20-29, PS 1583 and RVS 200-1, PS 1583 and JS 20-29 and PS 1042 and Pb1) genetic similarity. The average number of alleles per marker was 1.88, while percentage of all bands showed the polymorphism was 100%. The dendrogram constructed from SSR marker data divided twenty two genotypes into two main groups A and group B which consisted of seven clusters: Cluster I, II, III, IV, V, VI and VII. On the basis of dendrogram, genotypes PS 1225 and JS 20-59 was found to be most distant.
Open Access
Mapping drought tolerance using teosinte derived BC1F2 population of maize (Zea mays L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Amarjeet Kumar; Singh, N.K.
The present investigation was undertaken with wild progenitor teosinte (Z. mays ssp. parviglumis) and a maize inbred line DI-103.The 203 lines of BC1F2 mapping populations were phenotyped in two environmental conditions i.e. irrigated and moisture stress condition during the rabi season 2016-17 for twenty five morpho-physiological traits associated with drought tolerance. Phenotyped data were subjected to single marker analysis using forty three polymorphic markers. A total of 82 QTLs were identified to be associated with twenty four morpho-physiological traits except leaf firing. Out of 82 QTLs, four QTLs were found major QTLs and they were associated with anthesis silking interval, leaf rolling, plant height and thousand kernels weight. One major QTL linked with marker phi113 was detected for anthesis silking interval accounted for 11.79 per cent phenotypic variation. Marker umc1303 was linked with the major QTL responsible for 14.67 per cent phenotypic variation for leaf rolling .Two other minor QTLs were linked with the marker umc1444 and umc1156 explained 3.84 and 2.28 per cent of phenotypic variation for leaf rolling. The major QTL linked with marker umc1171 accounted for 13.25 per cent phenotypic variation for 1000 kernel weight. For the identification of drought tolerant lines rank score was used. The basis of ranking was the least reduction or positive increase between the performance of genotype in irrigated and moisture stress condition. Thirteen morpho-physiological traits from total of twenty five traits associated with the drought tolerance were used for identification of drought tolerant lines. Overall sum of rank scores for thirteen traits associated with drought tolerance revealed that AM-39 was the most drought tolerant genotype among all the 203 lines studied with total score of one hundred eight, followed by AM-64, AM-16, AM-42, and AM-102, whereas, AM-116 was the most susceptible with the least score of thirty four. The molecular characterization of five teosinte derived lines BC1 F4 reflected that the maximum allelic contribution lines from parent teosinte (Z. mays ssp. parviglumis) was found in the introgressed line AM-5 (53.4 per cent) followed by AM-12 (48.9 per cent), whereas, least contribution of 34.1 per cent was found in AM-7.The maximum contribution of 53.4 per cent from parent DI-103 was found in introgressed line AM-7 followed by AM-2 (42 per cent) and the least contribution was exhibited by AM-5 (27.3 per cent) followed by 33 per cent in the AM-12.The morphological characterization of teosinte derived BC1F4 lines exhibited that the yield contributing traits namely number of cobs ranged from 2 to 5. The maximum number of cob was found in AM-5 (5.00) followed by AM-2 (4.00). The largest variation in parents among all morphological traits was found in number cobs per plant i.e. inbred DI-103 (1.80), whereas, teosinte had 417 cobs. Ear length varied from 8.00 cm (AM-7) to 13.50 cm (AM-5). It is therefore, present findings might be concluded that the different morpho-physiological character associated with drought tolerance in maize and could be useful to combat the drought tolerance along with domestication of wild alleles.
Open Access
Genetics of resistance and molecular analysis of botrytis grey mould in chickpea (Cicer arietinum L.)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Bhardwaj, Rajneesh; Panwar, R.K.
Chickpea (Cicer arietinum L.) is the second largest consumed pulse crop of the world after common bean and it is grown in over 50 countries and traded across 140 countries. The beneficial effects of chickpea on soil health and human health are well recognized. There has been a slow progress in improving the average global productivity of chickpea, which continued to remain below 1.0-ton ha-1. In India, chickpea was planted in 8.25 million hectares during 2016-17 with a production of 7.33 million tons and a productivity of 859 kg/ha. However, the breakthrough in its productivity is still awaited because of the number of biotic and abiotic stresses constrain productivity. Botrytis gray mould (BGM) caused by Botrytis cinerea is one of the major constraints for low yield of chickpea. This disease leads to subsequent crop loss in certain parts of India (in Tarai area of Uttarakhand, Tal area of Bihar and in Punjab). The present investigation was carried out in Rabi seasons during 2014-15, 2015-16 and 2016-17 at N. E. Borlaug Crop Research Centre and Pulse Breeding Laboratory of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India with the objectives to study the genetics of resistance to botrytis grey mould (BGM) disease and molecular analysis of BGM disease in chickpea. The experimental material comprised of resistant parents viz., GL10006, DKG876 and susceptible parents viz., DCP92-3, GNG1581 and H 208. Screening for resistance to botrytis grey mould disease was done by using field screening technique which involves spraying artificial inoculums of a pathogen. Disease scoring was done using the 1-9 scale. Resistance was found dominant over susceptibility in the F1 generation of six resistant × susceptible crosses viz. GL10006×GNG1581, GL10006×DCP92-3, GL10006×H208, DKG876×GNG1581, DKG876×DCP92-3 and DKG876×H208. In the F2 generation, 3(resistant): 1(susceptible) ratio was found for all resistant × susceptible crosses indicating that resistance was governed by a single dominant gene. Backcross of F1 with resistant parents gave all resistant plants and backcross with susceptible parent gave segregants into 1(resistant): 1(susceptible) ratio. The crosses between resistant (GL10006) × resistant (DKG876) parents (test of allelism) suggested that the dominant resistance gene in both the parents were different as F2 generation of this cross showed segregation in15:1 ratio. In another experiment, STMS markers were tested for their association with botrytis grey mould resistance genes in parents, F1 and the F2 population of cross GL10006 (resistant parent) × H208 (susceptible parent) of chickpea. In preliminary studies, total 28 STMS was used out of which 13 primers viz., TA203, TA47, TA43, TS9, TAA137, ICCM068, ICCM0160, TA34, TS72, TA118, TS57, TA25 and TA144 were identified with polymorphic bands in the resistant and susceptible parent. These polymorphic primers were also screened in the F1 and F2 population. In F1 plants, amplified band size was similar to the resistant parent. Plants in F2 generation have amplified bands of either resistant or susceptible parents because in the F2 generation, plants were segregated into resistant and susceptible plants. To identify the putative marker-trait association, the genotypic and phenotypic data of cross between resistant parent (GL10006) and susceptible parent (H208) were subjected to single marker analysis. Results of single marker analysis indicated that five markers ICM0068, TS72, TA118, TA25 and TA144 were associated with BGM resistance. BGM resistance locus (QTL) associated with TA118 primer explained the most 28.25% of total phenotypic variation for BGM resistance. Whereas TA25, TA144, TS72, ICM0068 explained 0.05%, 5.5%, 7.85%, 0.39% of total phenotypic variation for BGM resistance, respectively. Polymorphic markers identified in the present study will be useful for identification of markers linked with BGM resistance which can further assist in marker-assisted selection for resistance breeding.
Open Access
Evaluation of drought tolerance potential in early generation progenies of sugarcane (Saccharum Sp. Complex)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Koujalagi, Deepak; Jeena, A.S.
The present investigation entitled “Evaluation of drought tolerance potential in early generation progenies of sugarcane (Saccharum Sp. Complex)” was conducted with 65 Bi-parental progenies along with parents and six check varieties viz., Co 0238, Co J 64 and Co Pant 03220 (early) and Co Pant 97222, Co Pant 05224, CoS 8436 (mid-late) to investigate drought tolerance potential based on physio-biochemical characters, studies on genetic parameters and revalidation of candidate gene specific molecular markers to aid breeding programme. The experiment was conducted in augmented block design- II in two seasons with two environments such as control at N.E.B.C.R.C. and stress at P. C.P.G.R. G.B.P.U.A&T, Pantnagar during spring 2017 and autumn 2017-18. The drought stress was created by withdrawing the irrigations during the 50 DAS to 200 DAS. The data was recorded on 16 physiological and biochemical characters for estimation of genetic parameters, genetic diversity analysis and selection indices. Further, Twenty five selected clones were utilized for candidate gene specific molecular markers validation study at Plant Biotechnology lab, Department of Genetics and Plant Breeding. Analysis of Variance (ANOVA) for four environments revealed that traits like proline content and leaf firing exhibited significant differences in stress unlike control environment indicating that these traits are of very high utility in selection for drought tolerance. The effect of water stress was clearly reflected by the reduced mean values for almost all the traits except an increase in proline content under stress. High PCV and GCV along with high heritability and high genetic advance as percent of mean was observed for CTD 60, CTD 120, CTD 180, Chl a, Chl b, Total chlorophyll, Total carotenoids Proline content, RWC % and Leaf firing indicating the prevalence of additive gene action in expression of these characters. Estimates of path coefficients revealed that Traits like Chl a, Chl b, total chlorophyll, SPAD 120, SPAD 180 and proline content were found to confer positive direct as well as indirect effects on DTC which supports their utilization as a reliable tool in selection for drought tolerance in sugarcane. Under both the environmental conditions highest inter-cluster distances were found to be between a drought tolerant cluster and a drought sensitive cluster. Cluster I, III and IV were found to comprise desirable clones for most of the traits. Germination percent, Chl a, RWC percent, leaf firing, total carotenoids, SPAD 60, Chl b, DTC and proline content contributed approximately 70 percent of the total divergence. Based on the selection scores the genotypes namely PC (2015-16)-55, PC (2015-16)-26, PC (2015-16)-40, PC (2015-16)-54, and PC (2015-16)-1 were found best ones among drought tolerant genotypes. Validation analysis of the marker trait association with respect to candidate gene specific markers and drought tolerance through t-test revealed that four markers DREB 1A, NAC 2, Snac 1 and LEA 3 recorded significant difference between the means of the two groups. The significant association proves their worth for future use of these markers in marker-assisted selection for drought tolerance in sugarcane.
Open Access
Pre-fertilization barriers, crossability, meiotic abnormalities and phenotypic characterization of inter-specific hybrids among Brassica species
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Joshi, Shikha; Pant, Usha
Interspecific hybridization is an important driving force in plant evolution and speciation. But not all of the crosses are successful, the cross incompatibility in the interspecific hybridizations has impeded the development of hybrids. A number of pre- and post-fertilization barriers limit the diversity of different genomic combination. The present investigation was carried out with the aim to get an idea of the crossability relationship among the species of Brassica, to study the pre-fertilization barriers that limit the formation of interspecific hybrid, phenotypic characterization of the interspecific hybrids recovered and to study the meiotic abnormalities during microsporogenesis of the interspecific hybrid. The investigation consisted of five Brassica species viz; B. rapa, B. nigra, B. juncea, B. napus and B. carinata. Field trials were carried out at N.E Borlaug Crop Research Centre, Pantnagar in rabi seasons of the years 2015-2016, 2016-2017 and 2017-2018. All the laboratory experiments were carried out following all the standard procedures in Cytogenetics and Molecular Marker Laboratory of the department of Genetics and Plant Breeding. Highest seed set percent was recorded for B. juncea × B. napus (28.89%) and lowest seed set percent was recorded for B. rapa × B. rapa (2.0%). High seed set (> 20% - <30%) was recorded for B. napus × B. rapa, B.carinata × B. nigra. Moderate seed set percent (> 10 % - < 20 %) was observed for B. nigra × B. juncea, B. napus × B. carinata, B. nigra × B. rapa, B. napus × B. nigra, B. juncea × B. Rapa while low seed set (>1% - <10%) recorded for B. carinata × B. rapa, B. juncea × B. nigra, B. napus × B. juncea, B. juncea × B. carinata, B. carinata × B. napus, B. rapa × B. juncea, B. carinata × B. juncea. Other crosses failed to set seed. Crossability of amphidiploid × amphidiploid crosses was highest among all of the crosses made and was followed by amphidiploid × diploid crosses and diploid × diploid crosses. Amphidiploids performed better as female parents in crosses between amphidiploids and diploids. Prefertilization barriers includes pollen tube abnormalities exhibiting coiling and bending of the tube, emergence of two pollen tubes from a single pollen grain, zigzag pollen tubes, swelling of pollen tube at the tip, pollen tube growing in wrong direction, branched pollen tubes, hairpin shaped pollen tube etc. Nature of the pollen tubes were however not specific to a particular cross. Pre-fertilization barriers were more prevalent in diploid × diploid crosses. The pollen germination percent showed highly significant and positive correlation with mean pollen tube growth, and percent siliqua set and highly significant and negative correlation with pollen tube abnormality percent. A highly significant and positive correlation also existed between mean pollen tube growth and siliqua set percent and a highly significant and negative correlation existed between mean pollen tube growth and pollen tube abnormality percent. Pollen tube abnormality percent had a highly significant and negative correlation with all of the crossability parameters with lack of correspondence with seed set percent. Siliqua set percent was found in correspondence with percent seed set. The morphology of interspecific hybrids was intermediate between both of the parents with predominance of female in some characters whereas in few crosses viz; B. napus × B. juncea and B. napus × B. carinata morphology of the hybrids resembled the female parent. The meiotic irregularities in the microsporogenesis of interspecific hybrids showed improper alignment of chromosomes at metaphase I and II, laggard chromosomes were also observed at anaphase I and II, bridge-fragment configuration at anaphase I and II and micronuclei at telophase II. These irregularities were however not specific to a particular interspecific hybrid. This study will help the breeders in choosing the parents and to decide the direction of the interspecific cross during gene transfer in wide hybridization in order to create novel genetic variation for crop improvement.
Open Access
Morphological, genetical and biochemical analysis of seed longevity in soybean [Glycine max L. (Merrill)]
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-06) Chourasia, Nishant Kumar; Singh, Kamendra
The present investigation was carried out with the objectives to identify sources for seed longevity based on screening of morphological and biochemical traits, study genetics of seed longevity and make use of line x tester analysis in predicting prepotency of the parents to identify the promising cross combinations in soybean based on heterosis, GCA and SCA effects for seed longevity along with seed yield. For field experiment 21 genotypes were screened for seed longevity and then three best were used as tester and six poorer genotypes were use as lines and crossed in a Line x Tester fashion for combining ability analysis and further six crosses were advanced to F2 generation for studying the genetics of longevity. The whole experiment were evaluated using completely randomized block design with two replications in Kharif 2016 and 2017 at N.E.Borlaug crop research centre, GBPUA&T, Pantnagar The analysis of variance for different characters revealed that highly significant differences among the treatments. Mean germination percentage of genotype after eight month of storage showed approximately the same germination after treating the freshly harvested soybean seeds with methanol. PS 1225 showed highest amount of ascorbate peroxidase, and catalase, while TGX 1681-3F recorded maximum enzymatic activity of superoxide dismutase and peroxidase. Four soybean genotypes viz. Bhatt. Kaliturr, TGX 1681-3F and PS 1225 were found to be very good storer. Germination percentage were found to be significantly negatively correlated with 100 seed weight, wrinkled seed coat, cracked seed coat percentage both at genotypic and phenotypic levels similarly germination percentage revealed highly significant and positive correlation with all biochemical traits. Germination percentage of F1s of Bhatt x Himso 1563, Kaliturr x PK 327, Kaliturr x Himso 1563, TGX 1681-3F x DT 21 and Bhatt x EC 241778 was towards low germinating parent suggesting dominance of low seed longevity over high longevity. Segregation pattern of crosses Kaliturr x PK 327, TGX 1681-3F X PK 327, TGX 1681-3F X DT 21 and Bhatt x EC 241778 in F2 revealed presence of one recessive gene whereas crosses, Bhatt x Himso 1563 and Kaliturr x Himso 1563 revealed presence of two recessive genes for high seed germinability. The Analysis of variance of line x tester analysis was found significant for all the characters undertaken. Estimates of variances due to specific combining ability (_2 SCA) were higher than the GCA variance for most of the characters except days to 50% flowering, number of seeds per pod and 100-seed weight, which indicated that most of the characters exhibited preponderance of non-additive gene action . The GCA effects indicated parental lines, VLS 59 and JS 335 to be the best general combiners and among testers, Bhatt emerged as a good general combiner for longevity. TGX 1681-3F x VLS 59 showed as excellent specific combiner for days to 50% flowering, Kaliturr x Himso 1563 for days to maturity, these crosses may be exploited to produce early maturing varieties.TGX 1681-3F x PK 327 emerged as outstanding specific combiner for number of branches per plant, number of pods per plant, number of seeds per pod, seed yield per plant, germination percentage, wrinkled seed coat and cracked seed coat percentage. Selection in the segregating generation of this cross is highly recommended for developing variety having high yield and seed longevity. The range of heterosis for germination percentage varied from -27.84 (TGX 1681-3F x Himso 1563) to 33.69 per cent (TGX 1681-3F x PK 327), -46.81 (TGX 1681-3F x Himso 1563) to 4.77 per cent (Kalitur x VLS 59) and -42.21 (TGX 1681-3F x Himso 1563) to 17.01 per cent (Kalitur x VLS 59) over mid, better and standard parents, respectively. TGX 1681-3F x PK 327 exhibited highly significant positive heterosis over mid parent and check parent for number of pod clusters per plant ,number of pods per plant and seed yield per plant. This cross also showed maximum amount of significantly negative heterosis over mid parent, better parent and check parent for cracked seed coat percentage. Kaliturr x VLS 59 showed maximum positive heterosis over both mid parent and check parent for germination percentage. TGX 1681-3F x VLS 59 showed maximum amount of significantly negative heterosis over mid parent, better parent and check parent for wrinkled seed coat percentage. It is therefore, concluded from the present research that four genotypes viz. Bhatt, TGX 1681-3F, Kalitur and PS 1225 should be used as a source of seed longevity whereas, cross TGX 1681-3F x PK 327 should be utilized in soybean crop improvement programme for high seed longevity and seed yield.

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