甘蓝型油菜(Brassica napus L.)耐淹性状的QTL定位分析

Mapping QTLs for waterlogging tolerance in Brassica napus L.

研究甘蓝型油菜苗期耐淹性的遗传规律,对选育耐淹性强油菜新品种,提高油菜产量有重要意义。本研究应用甘蓝型油菜品系WR-4（耐淹）和WR-5（不耐淹）杂交后代衍生的F2∶3家系群体为材料,于2012年和2013年连续2年进行淹水处理：全淹6 d后解除淹水恢复生长,解除淹水后第7 d调查死苗率,并以此作为油菜苗期耐淹性的鉴定指标,对该F2：3家系群体耐淹性进行鉴定。应用QTL Ici Mapping V3.2软件的完备区间作图法对该F2：3家系群体耐淹性进行QTL定位分析。结果表明,WR-4平均死苗率为31.0%（22.3%~39.7%）,而WR-5平均死苗率为72.1%（67.0%~77.2%）,亲本间死苗率差异显著（P〈0.01）。F2：3家系群体的死苗率呈偏正态分布,家系间死苗率平均为63.77%（2.0%~100.0%）。同一群体2年试验共检测到8个与耐淹性相关的QTL位点。2012年共检测到q WR1、q WR5、q WR9-1、q WR9-2和q WR17等5个QTLs,分别位于LG1、LG5、LG9和LG17连锁群上,贡献率为2.24%~47.58%;2013年共检测到q WR1、q WR9-1和q WR9-2等3个QTLs,分别位于LG1和LG9连锁群上,贡献率为3.02%~23.57%。其中q WR1、q WR9-1和q WR9-2在2年试验中均能检测到,其平均遗传贡献率分别为3.03%、15.87%和35.57%。表明,q WR1、q WR9-1和q WR9-2 3个QTLs位点可能与油菜苗期耐淹性相关,而q WR9-1和q WR9-2可能为控制油菜苗期耐淹性遗传的主效QTL。

Middle and lower reaches of Yangtze river is a main production and high yielding area of canola（Brassica napus L） in China.However,canola crop in this region is always in risk of seed yield loss caused by waterlogging.It is of importantce to map QTLs for waterlogging resistance in B.napus L for canola breeding as well as canola production.In this paper F2 ∶ 3population derived from the cross of WR-4（tolerant line） ×WR-5（susceptible line） was water-logged for two consecutive years,and the mortalities of7 d after relief from 6-d water logging both parental and F2 ∶ 3seedling were recorded as water-logging tolerance index.The mortalities of parents WR-4（an average of31.0%） and WR-5（an average of 72.1%） were significant difference and the mortality of F2 ∶ 3population（an average of 63.77%） was in skew distribution.Inclusive composite interval mapping revealed eight waterlogging tolerant QTLs in two years.Five QTLs including q WR1,q WR5,q WR9-1,q WR9-2 and q WR17 were located on the linkage groups of LG1,LG5,LG9,LG17,explaining 2.24% to 47.58% phenotypic variations in 2012,and three QTLs including q WR1,q WR9-1,q WR9-2 were located on the linkage groups of LG1,LG9,explaining 3.02% to 23.57% phenotypic variations in 2013.q WR1,q WR9-1,and q WR9-2 were detected in both years,explaining 3.03%,15.87% and 35.57% phenotypic variations.This indicates that q WR1,q WR9-1,and q WR9-2 could probably be associated with waterlogging tolerance in B.napus L and the former two might be the major QTLs controlling the inheritance of waterlogging tolerance.