Abstract: By the method of water culture, the low-phosphorus tolerance of 221 lines of Xieqingzao B//Xieqingzao B/Dongxiang wild rice BC₁F₉ populations was indentified. The morphological indices including plant height, leaf age, yellow leaf number, and shoot dry mass as well as the physiological indices including MDA, soluble sugar, and shoot phosphorus content were measured, also, the phosphorus efficiency was calculated, and the correlations among the indices were analyzed. All the 221 lines had differences in the seven test indices, and the low-phosphorus tolerance lines under low-phosphorus stress had higher values of relative leaf age, relative plant height, relative shoot dry mass, and relative soluble sugar content, but lower values of relative yellow leaf number and relative malondialdehyde content. The relative shoot phosphorus content had less difference. Phosphorus efficiency was positively correlated with phosphorus utilization efficiency and phosphorus uptake  efficiency, and the correlation between phosphorus efficiency and phosphorus utilization efficiency was at significant level (P<0.01), suggesting that the low-phosphorus tolerance capability of the low-phosphorus tolerance lines was mainly attributed to the high phosphorus utilization efficiency of the lines, namely, low-phosphorus tolerance lines had stronger capability in synthesizing dry mass with per unit phosphorus uptake.

Key words: Xieqingzao B//Xieqingzao B/Dongxiang wild rice BC₁F₉ populations, low-phosphorus tolerance, physiological mechanism