ALLELIC VARIATION, HETEROSIS AND COMBINING ABILITY IN OILSEED RAPE (Brassica napus L.)
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Date
2013
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Punjab Agricultural University, Ludhiana
Abstract
Brassica napus (L.) accessions from China, Australia and India were characterized for diversity at morphological and molecular level, for assessing their use in crop improvement programs. ZY-014, BLN-3189, and BLN-3324 were identified to be high yielding genotypes. Analysis of variance confirmed the presence of morphological diversity for all the traits. D2 analysis allowed formation of nine broad groups, largely reflecting geographic origin. Allelic information from 36 polymorphic SSR primer combinations amplified 407 alleles and allowed clustering of genotypes into four distinct clusters. Australian genotype RT-108 was the most distinct genotype. Line x tester (38 x 4) was designed to estimate the potential of evaluated genotypes for hybrid breeding, and to identify promising parents combinations. Importance of non additive variation was emphasised. BLN-3348 was best combiner for yield followed by ZY-007, BLN-3224 and BLN-3575. Among testers, Rivette and GSL-1 were positive contributors for yield. Maximum positive SCA was recorded for CC-05032 X GSL-1 followed by ZY-014 X Rivette. Significant positive yield heterosis over commercial check was indicated in 29 combinations.BLN-3224 X Rivette showed the maximum commercial heterosis (80.52%). Yield heterosis was mostly associated with early flowering, late maturity, SPAD value, and leaf area and branch number. Genetic distance was significantly correlated with per se values for main shoot length, siliqua length and seeds per siliqua. Combined genetic distance based on both molecular and phenotypic diversity was correlated with heterosis for oil content. The diverse genotypes identified during the study represent a useful resource for improving heterotic potential and diversifying the B. napus gene pool at PAU, Ludhiana.
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sowing, intercropping, wheats, tillage equipment, seed drilling, crops, mustard, fertilizers, land resources, chickpeas