水稻显性早熟材料D64B的发现、遗传分析和分子标记定位

D64B是从籼型杂交稻保持系D63B中发现的一个无色早熟突变株。用不育系、保持系、恢复系以及早稳型水稻品种与之杂交，F1的抽穗期多数与早熟亲本D64B相同或相近，部分偏向早熟亲本。这些结果表明D64B具有显性早熟特性。将D64B在海南陵水短日照和温江长日照下分期种植，观察到两地点因生长发育期间温度变化引起的抽穗期的变化的程度是一致的，并且在一定范围内随着生长发育期间温度升高，D64B抽穗缩短，可知D64B不感光，感温性中等。种植D64B与蜀恢527的正反交F2和回交一代BC1，三者的抽穗期均呈双峰分布，并且峰谷处于同一位置，以峰谷值103d为转折点进行分组，早熟与迟熟植株的分离比经x^2检验分别符合3：1和1：1，表明D64B的早熟特性主要受一对显性早熟核基因控制。用356对微卫星引物对亲本D64B和蜀恢527进行多态性分析，并用多态性引物扩增蜀恢527／D64B的F2早熟和迟熟近等基因池，找到多态引物RM279，进一步用RM279附近的微卫星引物扩增F2早熟和迟熟近等基因池、迟熟植株，筛到多态性引物RM71。用MAPMAKER／EXP3．0软件分析，将该早熟基因定位于第2染色体的短臂端，位于RM179和RM71之间，遗传距离分别为12．6cM和13．3cM，该基因拟名EF-3(t)。在育种实践中用D64B育成早熟不育系D64A。

The Discovery,Genetic Analysis and Gene Mapping of Earliness Rice (Oryza sativa L.) D64B

D64B,an achromatic early mutation,was discovered from indica rice preserver line D63B.D64B were crossed with inhomogeneous sterile lines,preserver lines and restorer lines,most of their F1 shared the same heading dates as D64B.The results indicated that D64B possessed the characteristic of dominant earliness.To analyze the earliness trait,positive and negative crosses F2 and BC1 from the cross of D64B and Shuhui 527 were cultivated.Their heading dates showed double apices distributing with same apex values.According to apex vale value-103 d,plants of the F2 and BC1 were separated into early plants and late plants,which were tested with χ2 value.The results suggested that the segregation ratio of number of early to late plant fitted to 3:1 and 1:1 for positive and negative cross F2 and BC1,respectively,and that the earliness of D64B was controlled by a single dominant major gene.To map the gene,the polymorphisms between D64B and Shuhui 527 was analyzed with reported 356 SSR primers and 59 primers showed polymorphisms.The earliness-lateness near isogenic pools,early plants and late plants from F2 of Shuhui 527×D64B were further amplified with the 59 primers.The results indicated that there were polymorphisms on both RM279 and RM71.Their results being analyzed with MAPMAKER/EXP3.0 software,the dominant major gene was located on the top arm of rice chromosome 2 and between the two SSR markers,RM279 and RM71,with genetic distance of 12.6 cM and 13.3 cM,respectively.According to reported data,the gene was first discovered and tentatively named as Ef-3(t).In breeding practice,sterile line D64A had been bred with D64B.