Comparison of the drought resistance characters at Seedling Stage between Dongxiang Common Wild rice (Oryza rufipogon Griff.) and cultivars (Oryza sativa L.)

Drought impacts rice growth and development no matter which stage it occurs,which ultimately results in yield reduction. Study on drought resistance of rice germplasm helps to improve cultivars and stabilize grain yield in water stressed conditions. Dongxiang common wild rice (Oryza rufipogon Griff. hereafter DXCWR) is recognized the progenitor of cultivated rice and may be valuable for increase of drought resistance in rice. Four accessions of the DXCWR collected from three survived populations,were compared with 15 cultivars on the seedling stage drought resistance. The resistance was measured with eight index traits which were evaluated in pot cultivation test with three replications. The DXCWR was more resistant to drought stress than other cultivars indicated by maximum root length ( MRL),stem length ( SL),dry root weight (DRW),fresh root weight (FRW),root relative water content (RRWC) and drought resistance index (DRI),but not by root/stem length ratio (RSLR) and root number ( RN). Among these eight traits,MRL,SL,DRW,FRW and RRWC contributed more than others to drought resistance for rice seedlings. The four accessions of the DXCWR were tremendously differentiated on drought resistance expressed by comprehensive drought resistance value and drought resistance index,and accession 16 from Shuitaoshuxia population was the best. The drought resistance of DXCWR was related with the original habitats. As a result,the DXCWR could be germplasm resources for improvement of drought resistance in rice.