QTL Identification For Oil,Protein,Glucosinolate And Erucic Acid Contents Based On Embryo And Maternal Genetic Systems In Rapeseed(Brassica Napus L.)

Rapeseed (Brassica napus L.) is a major oilseeds crop around world, which plays a significant role in agricultural production and oil supply. With the increasing requirement for consumers, it is important to improve rapeseed quality by breeding. Most important nutrition quality traits in rapeseed such as oil, protein, glucosinolate and erucic acid contents belong to the complicated quantitative traits which are simultaneously controlled by genetic effects from different genetic systems including embryo and/or maternal nuclear genomes. It is, hence, necessary to reveal their genetic mechanism for these traits in rapeseed, especially in the QTL identification based on these two different genetic systems under different environments.In present study202TN DH and their parents, Tapidor and Ningyou7, were used to construct177BC1F1and181BC2F1populations for mapping the QTLs with the embryo genetic main effects, the maternal genetic main effects and the environmental interaction effects of oil, protein, glucosinolate and erucic acid contents in rapeseed, using the newly developed QTL mapping methods and corresponding mapping software considering two genetic systems for quality quantitative traits in dicotyledonous crop seeds. Differences in QTLs distribution between these two genetic systems, which control the performance of quality quantitative traits across environmental conditions, were analyzed. The results are as follows:It was observed that nineteen QTLs for oil, protein, glucosinolate and erucic acid contents of rapeseed were distributed in different linkage groups. Among them, four QTLs associated with oil content were located in Al, A4, A6and C2linkage groups, with the name of qOC-1-1, qOC-4-2, qOC-6-3and qOC-12-4. All QTLs detected for oil content in present study could explain59.5%of the phenotypic variation, in which qOC-6-3was the major QTL controlling oil content in present experiment, explaining36.3%of the phenotypic variation. These QTLs were all detected with extremely significant embryo and maternal additive main effects, in which three had extremely significant embryo dominant main effects and one QTL with weekly significant embryo and maternal additive interaction effects. Three QTLs for protein content were identified in A4, A7and C5linkage group, respectively, named as qPC-4-1, qPC-7-2and qPC-15-3, which could total explain49.1%of the phenotypic variation. Of them, qPC-4-1detected as the major QTL had the phenotypic contribution of37.9%for protein content of rapeseed. All QTLs were found to have extremely significant embryo and maternal additive main effects, while only one was detected with embryo dominant main effect. No QTL×environment interaction effect was found for these QTLs.Nine QTLs controlling glucosinolate content were discovered to locate in A3, A4, A8, A9, C1, C2, C1and C9linkage group, namely qGSLC-3-1, qGSLC-4-2, qGSLC-8-3, qGSLC-9-4, qGSLC-11-5, qGSLC-12-6, qGSLC-12-7, qGSLC-17-8and qGSLC-19-9, respectively. All QTLs could explain83.8%of phenotypic variation and had extremely significant embryo and maternal additive main effects, in which five were found with significant embryo dominant main effect. Besides, one QTL was detected with slightly significant QTL×environment interaction effect.Three QTLs for erucic acid content, named as qEAC-7-1, qEAC-8-2and qEAC-13-3, were found to be distributed in A7, A8and C3linkage group in rapeseed with significant QTL embryo additive and maternal additive main effects, which could explain89.7%of the phenotypic variation. Among these QTLs, two were found to have weekly QTL×environment interaction effects.