[Drought resistance evaluation system for backcross lines of Dongxiang common wild rice (Oryza rufipogon Griff.)]

A total of 79 rice materials containing Dongxiang wild rice (Oryza rufipogon Griff. ) backcross lines (Dwr)/Xie-qingzao B (Xqz B)//Xqz B and their parents were chosen as the test objects to study the relationships between the drought resistance of these materials and the 31 drought resistance indices at germinating stage, seedling stage, booting stage, and mature stage. The results showed that the drought resistance index or the drought resistance coefficient of these materials were significantly correlated to the relative germination energy (RGE) under 15% PEG-6000 drought stress, the germination drought resistance index (GDRI) and relative germination energy (RGE) under 20% PEG-6000 drought stress, and the relative value of maximum root length (MRL), seeding height (SH), fresh root mass (FRM), dry root mass (DRM), root relative water content (RRWC), wilting rate (WR), leaf soluble sugar content (LSSC), leaf proline content (LPC), leaf MDA content (LMDAC), leaf relative water content (LRWC), level of rolling leaf (RL), plant height (PH), tiller number per plant (TNP), productive tiller number per plant (PTNP), filled spikelets per panicle (FSP), panicle density (PD), seed setting rate (SR), and 1000-grain mass (TGM) under water stress. Through stepwise regression analysis, nine drought resistance indices including the RGE under 20% PEG-6000 drought stress and the relative values of DRM, RRWC, LSSC, LPC, LMDAC, ETNP, SR, and TGM under water stress were selected. Base on these indices and their partial correlation coefficients, the drought resistance evaluation equation (D value) and evaluation system were established, which could well assess the drought resistance of the Dongxiang common wild rice backcross lines at different growth stages.