一份新型水稻极度分蘖突变体的遗传分析及分子标记定位

在三系杂交水稻保持系绵香1B（M1B）和一个雄性不育材料GMS-1的杂交后代中发现一株极度分蘖突变体（命名为ext．M1B），其分蘖数为121。对ext-M1B与5个正常分蘖水稻品种杂交F1和F2代的遗传分析表明，ext-M1B的极度分蘖特性受一对隐性核基因控制。以2480B／ext-M1B的F2代作定位群体，用分子标记将ext-M1B的突变基因定位于水稻第6染色体短臂，该基因与微卫星标记RM197、RM584和RM225的遗传距离分别为3．8cM、5．1cM和5．2cM，认为ext-M1B突变基因是一个新的水稻极度分蘖基因，暂命名为ext-M1B（t）。

Genetic Analysis and Molecular Tagging on a Novel Excessive Tillering Mutant in Rice

A rice (Oryza sativa L.) mutant with an excessive tiller number, designated ext-M1B, was found in the F2 progenies gen-erated from the cross between M1B and GMS-1 (a genetic male sterile), whose number of tillers was 121. The excessive tillering mutant also resulted in significant changes in plant height, flag leaf , stem, filled grains per panicle, and productive panicles per plant. The inbreeding progenies of ext-M1B exhibited the same mutant phenotype. The crosses from ext-M1B/M1B, M1B/ext-M1B, 2480B/ext-M1B, D62B/ext-M1B, G46B/ext-M1B, and G683B/ext-M1B expressed normal tillering in F1, and segregated into two different phenotypes of normal tillering type and excessive tillering type in a ratio of 3:1 in F2. Inheritance analysis indicated that the excessive tillering character was controlled by a single recessive nucleic gene. By BSA (bulked segregants analysis) and mi-crosatellite makers with the F2 population of 2480B/ext-M1B as the mapping population, RM197, RM584, and RM225, all of which were located on the short arm of rice chromosome 6, were identified to be linked with the excessive tillering gene with ge-netic distance of 3.8 cM, 5.1 cM, and 5.2 cM, respectively. This gene is probably a new excessive tillering gene in rice and is des-ignated tentatively ext-M1B (t).