一个新的水稻白化转绿突变体G9的特性研究

利用60Coγ射线离体诱变籼稻光温敏核不育系广占63S,获得一个新的白化转绿突变体G9。该突变体从出苗到4叶1心期,叶色表现出明显的白化现象,从第4新生叶开始,新老叶片开始转为正常绿色,到6叶1心时秧苗完全转绿;在2叶期,其叶片叶绿素含量极少,随着叶色转绿,叶绿素含量开始显著增加,4叶期约为亲本的1/4,而至6叶期,突变体和亲本的总叶绿素含量无显著差异。遗传分析表明,该突变体的叶色白化转绿变异受一对隐性核基因控制。用144个SSR标记分析了突变体和亲本的SSR组型,未发现两者之间存在差异,说明该突变体确系诱发突变而来,两者存在很好的近等基因特性。对G9/AM6的F4代的农艺性状进行比较,发现突变基因对幼苗总根数、白根数、最长根长度和苗期株高均有显著影响;对植株分蘖能力、成熟期株高、单穗实粒数、结实率、千粒重、单株产量均有显著影响,而对有效穗数无明显影响。

CHARACTERIZATION OF A NEW ALBINO GREEN-REVERTIBLE MUTANT G9 OF RICE

A new albino green-revertible rice mutant G9 was isolated from an indica photo-thermo-sensitive genic male sterile rice variety Guangzhan 63S using 60Co γ|irradiation in combination with in vitro tissue culture. G9 exhibited an abnormal albino phenotype up to L4 stage, then the seedling entered into a transit period when old and newly extended leaves gradually revert to partial green and full green when L6 leaf fully emerged out. There was very low chlorophyll content in seedlings at L2 stage of mutant, however, with  leaves change into green, the total chlorophyll (Chla and Chlb) content notably increased in G9, about 1/4 of that in Guangzhan 63S at L4 stage, and almost identical to the latter at L6 stage. Genetic analysis showed that the green-revertible albino trait of the mutant was controlled by a single recessive nucleic gene. Analysis of 144 microsatellite (SSR) markers showed that G9 had the same SSR haplotype as wild-type, demonstrating that G9 was surely generated through mutation of Guangzhan 63S and both are highly isogenic lines. Comparative analysis on F4 agronomy traits of G9/AM6 indicated that the mutated gene significantly affected total root number, white root number, length of the longest root and plant height at seedling stage; tillering ability, plant height, grain number per panicle, grain setting ratio, 1000|grain weight as well as yield per plant at maturity were also affected by the gene significantly, but the gene didn’t affect the effective tillers per plants.