Seed heteromorphism, seed quality assessment, genetic divergence and stability analysis in cowpea [Vigna unguiculata (L.) Walp]
| dc.contributor.advisor | Verma, J.S. | |
| dc.contributor.author | Prasad, Shambhoo | |
| dc.date.accessioned | 2017-12-06T07:18:53Z | |
| dc.date.available | 2017-12-06T07:18:53Z | |
| dc.date.issued | 2016-12 | |
| dc.description.abstract | The present investigation was carried out with 28 cowpea varieties over three seasons of Kharif -2013, Kharif-2014 and Kharif -2015. The field experiments were conducted in Randomized Complete Block Design (RCBD) while under laboratory conditions the experiments were laid out in Complete Randomized Design (CRD) with three replications. The observations under field and laboratory conditions were recorded on 10 randomly selected plants or plant parts, seeds as well as seedlings as per the standard procedure. Seed heteromorphism studies showed considerable variability among cowpea varieties that might be helpful in developing specific seed processing equipments which can be used for upgrading the seed from harvested bulk seed lots. Seed coat texture, colour, shape and hilum colour can be used for identification of specific variety. Seed hydration capacity, hydration index, swelling capacity and swelling index help to understand the property of seed coat texture, which is used for the assessment of cowpea seed cooking properties. Water uptake by white/creamy white seed coated varieties was more rapid than black, red, light brown to dark brown coated seeds, while seeds with gray mottled coat imbibed slowly. Imbibition pattern showed genotypic differences, of which vegetable (Kashi series) and grain type (PL-1 and PL-2) varieties imbibe more rapidly causing imbibition damage than forage type varieties. Lower field emergence recorded in vegetable (Kashi series) and grain type (PL-1 and PL-2) varieties was associated with more imbibition damage than forage type varieties as confirmed by electrical conductivity test which is used for seed vigour classification. Germination test, seedling growth test and germination related indices were used for seed quality assessment. Maximum values for almost all the seed quality parameters was recorded in UPC series and other forage type varieties than Kashi series and grain type varieties. Higher value of normal seedling, root and shoot length, vigour index I, vigour index II, speed of germination, relative growth index and lower value of time taken to complete 50 per cent germination and mean germination time indicated the vigour potential of varieties, thus these parameters can be used to assess the seed quality and planting value of seed lot that will help farmers in taking decision to select the appropriate variety for sowing. Almost all the seed quality parameters showed significant correlation with field emergence except standard germination (SG), germination index (GI), mean germination time (MGT), mean daily germination (MDG) and membrane integrity (MI). Therefore, the normal seedling percentage, vigour index-I, vigour index-II, speed of germination, time to 50 per cent seed germination and imbibition damage tests can be used to predict the field emergence potential of cowpea seed lots. Maximum values of genotypic and phenotypic coefficient of variability were recorded for plant height, seed yield per plot, pod length, 100-seed weight and seed length. Higher heritability coupled with moderate to high genetic advance found for all the characters except number of branches per plant also indicated that selection would be effective for these traits. Thus, development of an ideal variety which may performe better under changing climate can be undertaken by using better donor parent for the crossing nursery. For the identification of stable varieties the AMMI model was used. The combined analysis of variance showed that environment was dominant source of variation for almost all the characters. Genotype x environment interaction further divided, of which the first interaction principal component axis (IPCA-I) contributed more than 70 per cent G x E interaction variation while remaining variability contributed due to residual effect. The cowpea varieties UPC 622 (4), UPC 5286 (1), UPC 8705 (12) and IL-1177 (23) were found less interactive with test environment because these varieties scored lower IPCA-I value and seed yield was higher than average seed yield , thus considered as most stable varieties across the environments for seed yield. Therefore, it is concluded that the selection during breeding programmes for lines showing slow rates of imbibition and low incidence of imbibition damage may lead to improved seed vigour and the combination of seed quality assessment methods instead of germination test can be used to predict the planting value of seed lots. For the development of high yielding stable varieties, the appropriate donor parents having better yield potential as well as less interactive with test environments can be used in breeding programme. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810037010 | |
| dc.keywords | heteromorphism, seed quality, genetic diversity, stability, cowpeas, Vigna unguiculata | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 320 | en_US |
| dc.publisher | G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand) | en_US |
| dc.research.problem | Cowpeas | en_US |
| dc.sub | Vegetable Science | en_US |
| dc.subject | Genetics and Plant Breeding | en_US |
| dc.theme | Genetics | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Seed heteromorphism, seed quality assessment, genetic divergence and stability analysis in cowpea [Vigna unguiculata (L.) Walp] | en_US |
| dc.type | Thesis | en_US |