水稻核心种质资源的苗期耐冷性鉴定与评价

苗期冷害是一种影响水稻群体建成和生长发育的延迟性冷害,最终导致水稻减产。筛选苗期耐冷性强的种质资源可以为水稻耐冷育种提供亲本资源。本研究采用3000份全球水稻核心种质资源中的1542份在人工气候箱进行苗期耐冷鉴定及评价,以存活率为评价指标。发现种质资源苗期耐冷性变异非常丰富,筛选出存活率80%以上的苗期耐冷资源材料73份,其中籼稻9份,温带粳稻47份,热带粳稻4份,粳稻混合型8份,籼粳中间型和香稻类型各1份,籼粳混合型3份,XI-B、XI-2和亚热带粳稻中未筛选到苗期耐冷材料。耐冷材料主要集中在温带粳稻中,但亦有部分籼稻材料表现出较强的耐冷性。多数苗期耐冷资源材料的综合农艺性状较差,结合株高、生育期性状等筛选出14份半矮秆和生育期适中的强耐冷性材料,可作为水稻苗期耐冷育种亲本应用。对利用种质资源开展苗期耐冷基因挖掘和选育全生育期耐冷品种进行了讨论。本研究初步阐明了水稻耐冷种质资源的分布,为水稻耐冷育种提供了优异的供体亲本材料。

Identification and Evaluation of Cold Tolerance of Rice Core Germplasm Resources at Seedling Stage

Chilling damage at seedling stage is a kind of cold-induced delayed damage which affects the growth and development of rice population and finally leads to the decrease of rice production.Screening germplasms with strong cold tolerance(CT)at seedling stage will provide useful parents for rice breeding of CT.In this study,1542 of 3000 global rice germplasms resources were used for cold tolerance identification and evaluation at seedling stage in an artificial climate box,with survival rate as the evaluation index.The results indicated that tremendous variations exist in germplasms and total of 73 accessions were screened based on the index of survival rate over 80%,including 9 from xian,47 from temperate geng,4 from tropical geng,8 from geng mix type,1 from each of xian-geng intermediate type and fragrant type,and 3 from xian-geng mix type.No CT germplasm was screened out from two xian types(XI-B,XI-2)and subtropical geng.CT germplasms were majorly selected from temperate geng and partially from xian.Most CT germplasms show poor agronomic traits.Combined with performances of plant height and heading date,14 accessions with strong CT and semidwarf as well as suitable growth duration were selected,which is suitably used for donor parents for rice breeding of CT.It was discussed that mining favorable genes for CT at seedling stage and breeding variety with whole growth duration CT using germplasms.The results preliminarily expounded the distribution of cold tolerant germplasms and provided excellent materials used as donor parents for rice breeding of cold tolerance.