Heterosis and combining ability in oil contents of Brassica napus L.in different ecological regions

【Objective】 The heterosis and combining ability in oil contents of Brassica napus L.were studied in two ecological regions.【Method】 Thirty reciprocal crosses were made with 6 Brassica napus L.lines with different oil contents and genetic backgrounds as parents based on the Griffing Model Ⅰdesign,and a total of 36 accessions including 30 reciprocal crosses and 6 parents were planted in a randomized complete block design in two different ecological regions,spring rape area in Zhangye,Gansu province and winter rape area in Dali,Shaanxi province.Heterosis and combining ability in oil content were analyzed,and environmental effects were preliminarily observed.【Result】 Only a few crosses exhibited over-parent heterosis in both ecological regions and most crosses exhibited certain mid-parent heterosis in spring rape area.The heterosis of oil content was various in different ecological regions,but the combinations with heterosis were generally consistent.The broad sense heritability of oil content was over 90% and the narrow sense heritability of oil content was more than 80%.The variances of both general combining ability and specific combining ability in oil contents were highly significant.The values of combining ability were variable in different ecological regions but the exhibitions were basically consistent.The reciprocal cross effect of oil content was highly significant in spring rape area but was not detected in winter rape area.【Conclusion】 The inheritance of oil content of Brassica napus L.was mainly controlled by additive gene effect with affects from non-additive effect simultaneously.High-oil line with high general combining ability(GCA) are suitable parents in hybrid rapeseed development for high oil content and the reciprocal effects should be considered in the determination of spring rapeseed hybrid crosses.