Genetic Analysis for Yield and Quality Traits in Brassica napus L.

Abstract

An experiment was conducted to estimate genetic variability and heterosis in rapeseed (Brassica napus L.) for important traits using eight genotypes (Rainbow; R.B, Rustam Canola; R.C, Dunkled; D.K, Abasin-95; A-95, NIFA Gold; N.G, Durre-NIFA; D.N, Punjab Sarson; P.S and Faisal Canola; F.C) and their crosses. In year 2014-15, these genotypes were crossed in diallel fashion to generate F1 hybrids. In year 2015-16 parents and their F1 hybrids were field evaluated in RCBD with two replications. Data were recorded for days to flowering, maturity, plant height, primary branches plant-1, secondary branches plant-1, pods main raceme-1, pods plant-1, pod length, seeds pod-1, 1000-seed weight, seed yield plant-1, oil, protein, linolenic acid, glucosinolate and erucic acid content. The analysis of variance revealed significant differences at P ≥ 0.01 levels among genotypes for all studied traits indicating the presence of genetic variability in this set of germplasm. On the basis of mean performance, parental genotype A-95 and hybrid F.C × R.C were found best for primary branches plant-1, secondary branches plant-1, pods main raceme-1, pods plant-1, pod length, Seeds pod-1, 1000-seed weight, seed yield plant-1, linolenic acid and glucosinolate content. Parental genotypes, D.N and P.S and F1 hybrids D.K × D.N and A-95 × N.G were better for oil and erucic acid content. For flowering heterotic values were -0.96 to -11.83% for mid, -1.10 to -15.74% for better and -1.58 to -8.08 for commercial parent. Heterotic values for maturity ranged from -0.95 to -8.73%, -0.87 to -11.37, -0.88 to -6.88 for mid, better and commercial parents, respectively. For both flowering and maturity cross D.K× R.C performed better. In case of seeds yield plant-1, heterotic estimates ranged from 5.61 to 133.59%, 8.01 to 132.54% and 2.23 to 97.05 over mid, better and commercial variety. Heterotic values for oil content ranged from 4.44 to 26.15%, 3.86 to 25.12% and 4.02 to 18.70 over mid, better and commercial parent. F1 cross F.C × R.C performed best for seed yield and R.B × D.K for oil content. For glucosinolates content, crosses A-95 x P.S with maximum desirable negative values for mid parent (-69.84), better parent (-79.24) and commercial parent (-80.04) was found best. The study found several crosses with desirable negative heterotic effects for flowering, maturity, linolenic, glucosinolate and erucic acid content. A number of F1 crosses have been identified with desirable positive heterotic effects for yield contributing traits. The selection of desirable heterotic crosses at an early stage is very important in developing high yielding genotypes therefore these crosses could be recommended to include in breeding programs to improve seed yield and oil quality in rapeseed.