Abstract:

The drought and scarcity of water resource are more and more serious, and restrict agricultural development, specially rice production in China. Dongxiang common wild rice distributed in the most north region all over the world contains plentiful genetic diversity and excellent genes encoding drought resistance, cytoplasm male sterility (CMS), cold tolerance, fertility restoration, and so on. Screening drought resistance of dongxiang common wild rice is important for breeding rice with drought resistance and creating new drought resistance resource in current cultivated rice.
With the water stress and non-stress treatments designed, twelve morphological and physiological traits correlating with drought resistance were monitored in whole growth period for the back-cross inbred line population (R974//DongYe/R974) BC₁F₅, which were plant height (PH), tillers number per plant (TNP), effective tillers number per plant (ETNP), spikelets per panicle (SP), filled spikelets per panicle (FSP), length of panicle (LP), panicle density (PD), 1000-grain weight (TGW), seed setting rate (SR), grain weight per plant(GWP), leaf relative water content (LRWC), and level for rolling leaf (LRL). GWP is the most sensitive trait that is influenced by drought. Single variable stepwise regression, path analysis, gray correlative analysis, and multiple partial correlations analysis were conducted between the relative value of various traits and drought resistance coefficient. The results showed that six traits including LRWC, TNP, ETNP, TGW, PH, and ETNP significantly influenced the drought resistance and could be the indices to identify the drought resistance in rice. The D value of six traits elected was comprehensively used to evaluate the drought resistance by subordinate function values analysis, the results showed six index traits were feasible to predict the drought resistance in rice for whole growth stage. Four different drought resistance evaluated methods were compared, which indicated the drought resistance index is the best one for drought resistance direct evaluating.

Key words: Dongxiang wild rice, Drought resistance, Drought resistance index, Whole growth period