东乡普通野生稻与栽培稻苗期抗旱性的比较

干旱影响水稻生长发育,不论什么时期发生最终都导致产量损失。研究水稻资源抗旱性有助于水稻抗旱改良和稳定干旱胁迫下水稻的产量。东乡普通野生稻被公认为是栽培稻的祖先,对增强水稻抗旱性可能十分重要。对4份来自3个仅存的居群的东乡野生稻与15份栽培稻进行苗期抗旱性比较,考察了3次重复的盆栽土培试验中8个抗旱指标。表明东乡普通野生稻比栽培稻更为抗旱,表现在最大根长、茎长、根干重、根鲜重、根干鲜重比及抗旱指数等6个性状,而不表现在根数及根茎长比;其中茎长、最长根长、根干重、根鲜重及根系相对含水量对水稻苗期抗旱性影响更大。采用抗旱指数和抗旱总级别值法对水稻抗旱性进行评定,结果表明4份东乡野生稻材料间的抗旱性存在很大差异,且来水桃树下居群的抗性最高,东乡野生稻抗旱性可能与其原生境状况有关。结果认为东乡普通野生稻可作为栽培稻抗旱改良的遗传资源。

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.