Comparative Study on the Drought-tolerance between 4 High Yield Paddy Rice Varieties and Brazil Upland Rice Variety

The difference of drought-tolerance between 4 high yield paddy rice varieties(V989, Shanyou 198, Peiliangyou Teqing, Liangyou 681) and Brazil upland rice IAPAR-9 was studied by withholding water in summer hot climate at their vegetative stage and in phytotron at their reproductive stage respectively. The results were as follows:(1) When their leaves wilted (not restorable), the water content(6.1%-8.5%)within pot soil for 4 paddy rice varieties was significantly or much significantly lower than that for upland rice IAPAR-9(9.2%);(2) Watering again 3 or 5 days after their leaves wilted, the 4 paddy rice varieties could ratoon, but upland rice IAPAR-9 didn't have the ability; (3)The influence of drought on yield and yield components of the 4 paddy rice varieties was significantly or much significantly less than that of upland rice IAPAR-9. These results indicated that the drought-tolerance of the 4 high yield paddy rice varieties was greater than that of Brazil upland rice IAPAR-9. Among 4 paddy rice varieties, the best two drought-tolerance varieties were V989 and Shanyou 198, Peiliangyou Teqing next, and Liangyou 681 worst.