东乡野生稻苗期耐冷性的遗传分析

Genetic Analysis of Cold Tolerance at the Seedling Stage in Dongxiang Wild Rice (Oryza rufipogon)

以强耐冷材料龙稻5号(Oryza sativa ssp.japonica)和冷敏感材料协青早B(O.sativa ssp.indica)为对照品种,以萎蔫率和死苗率为鉴定指标,利用江西东乡普通野生稻(O.rufipogon)/协青早B//协青早B构建的回交重组自交系(backcross in-bred lines,BILs)群体(BC1F9)进行苗期耐冷性鉴定和遗传分析。结果表明,10°C冷处理7天后,228个BILs群体的平均萎蔫率为67.4%,平均死苗率为70.8%。将死苗率≤20%的株系,在更低温度(8°C昼/5°C夜)下处理5天,结果显示5243和5335为强耐冷材料,可用于构建东乡野生稻QTL(quantitative traitloci)近等基因系(near-isogenic lines,NILs)。实验结果显示,群体萎蔫率和死苗率均呈偏态的连续分布,暗示东乡野生稻苗期耐冷性表现为质量-数量性状遗传特征,由主基因-多基因控制。

We examined the cold tolerance of seedlings of a BILs population （BC1F9） of Dongxiang wild rice （Dwr）/Xie-qingzao B （Xqz B）//Xqz B by cold treatment assay and genetic analysis. The control materials included the strong cold-tolerant variety, Longdao 5, and the cold-sensitive cultivar Xqz B, using seedling wilting rate and seedling mortality rate as evaluation indices. After cold treatment （10°C） for 7 days, the mean seedling wilting rate and seedling mortality rate for 228 BILs were 67.4% and 70.8%, respectively. The lines with only 20% seedling mortality rate or below were further treated with a colder temperature of 8°C day/5°C night for 5 days. The lines 5243 and 5335 were the most cold-tolerant and may be useful for constructing quantitative trait loci-near-isogenic lines of Dwr. Moreover, the skew-normal and continuous distribution of seedling wilting and mortality rates suggest that cold tolerance at the seedling stage in Dwr represents the inheritance of qualitative-quantitative traits which are controlled by major genes and polygenes.