Study On Heterosis And Inbreeding Depression In Agronomic And Oil Quality Characters Of Rapeseed (Brassica Napus L.)

Heterosis is defined as the superiority of a hybrid over its parents. Inbreeding depression called as the decreasing of hybrid vigour due to inbreeding. The present investigation was carried out to study heterosis and inbreeding depression in rapeseed. The seven diverse parents were crossed in all possible combinations. Forty-two F1S along with seven parents were planted in randomized complete block design with two replications over three environments. Inbreeding depression was calculated for fourteen and heterosis for twenty-one characters. Glucosinolate, oil content and fatty acids measured by spectrophotometer, NMR and gas chromatograph sets, respectively. TERI(OE)RI5 x TERI(OE)R983 showed high negative heterobeltiosis for days to 50% f10wering and days to maturity, it is suitable hybrid for development of early cultivars. TERI(OE)R983xHNS9801 exhibited high negative heterobeltiosis for plant height. Results showed that heterosis breeding was not suitable for development of dwarf cultivars. The highest positive heterobeltiosis for seed yield/plant over three environments was observed in GSC3A00xHNS9801with mean performance of 14.3 grams. Mean of inbreeding depression was 45.63% in this hybrid. Results showed that heterosis breeding was suitable method to increase seed yield. In most of hybrids oil content showed negative heterobeltiosis over three environments. Mean of inbreeding depression in this characters was 2.39%. Results showed that selection for high oil content was more effective than hybrid production. The highest negative heterobeltiosis for glucosinolate concentration over three environments was observed in GSC3A00xNPN02. The lowest glucosinolate concentration was observed in GSC3A00xTERI(OE)R983 with mean performance of 80.6 ?mol/g,.For oleic acid content, there was no cross with positive and significant heterobeltiosis over three environments. The highest negative heterobeltiosis for linolenic acid content was observed in HNS9802xNPN01 with mean performance of 10.7% The highest negative heterobeltiosis for erucic acid content was observed in TERI(OE)R983xGSC3A00 with mean performance of 2.3%. It showed that heterosis breeding was not suitable for development single zero cultivar. Characters with low and high inbreeding depression could be basically controlled by additive and non-additive gene action, respectively