Comprehensive metabolomic, proteomic and physiological analyses of grain yield reduction in rice under abrupt drought-flood alternation stress.

Abrupt drought-flood alternation (T1) is a meteorological disaster that frequently occurs during summer in southern China and the Yangtze river basin, often causing a significant loss of rice production. In this study, the response mechanism of yield decline under abrupt drought-flood alternation stress at the panicle differentiation stage was analyzed by looking at the metabolome, proteome as well as yield and physiological and biochemical indexes. The results showed that drought and flood stress caused a decrease in the yield of rice at the panicle differentiation stage, and abrupt drought-flood alternation stress created a synergistic effect for the reduction of yield.

[Effects of different nitrogen application rates on low temperature resistance of late rice at heading and flowering stage.].

Four levels of nitrogen application (N, low nitrogen, 90 kg N·hm; N, normal nitrogen, 180 kg N·hm; N, high nitrogen, 250 kg N·hm; N, ultra high nitrogen, 330 kg N·hm) were set to examine the effects of nitrogen application on the growth and development, yield formation and related physiological characteristics of late rice under low temperature condition during heading and flowering stage, with super hybrid late rice variety Wufengyou T025 as test material. The results showed that yield of all treatments decreased in different degrees under the low temperature conditions, with the yield of N being the highest, and N the lowest. The effective panicles per plant and total grains per panicle in N and N were higher than those of the other treatments, but their seed setting rate and harvest index were significantly decreased.

QTL mapping and correlation analysis for 1000-grain weight and percentage of grains with chalkiness in rice.

The study of 1000-grain weight (TGW) and percentage of grains with chalkiness (PGWC) is very important in rice. In this study, a set of introgression lines (ILs), derived from Sasanishiki/Habataki with Sasanishiki as the recurrent parent, were used to detect correlations and quantitative trait loci (QTL) on TGW and PGWC in two different environments. Phenotypic correlation analysis showed that there was no significant correlation between TGW and PGWC in both environments, which indicated that the linkage of TGW and PGWC traits could be broken via suitable population.

[Low-phosphorus tolerance and related physiological mechanism of Xieqingzao B//Xieqingzao B/Dongxiang wild rice BC1F9 populations].

By the method of water culture, the low-phosphorus tolerance of 221 lines of Xieqingzao B//Xieqingzao B/Dongxiang wild rice BC1 F9 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.