Genetic Analysis of Cold Tolerance at the Seedling Stage in Dongxiang Wild Rice (Oryza rufipogon)
东乡野生稻苗期耐冷性的遗传分析

We examined the cold tolerance of seedlings of a BILs population (BC1F9) of Dongxiang wild rice (Dwr)/Xieqingzao 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 coldtolerant 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.