Genetic Analysis And Gene Location Of Rice Multi-pistil Mutant Mp3

The paper studied a naturally occurring multi-pistil rice (Oryza sativa L.) mutant, which was found in the progeny of a breeding material from indica/japonica subspecific cross. The mutant is a good material to study the floral development, particularly the ovary and the style in the pistil. The author studied the floral anatomical structures, genetic analysis and gene location of the rice multi-pistil mutant mp3. The main results as followed:1 Phenotypes of the multi-pistil mutants' floral organs: these mp3 mutants showed multi-pistil compared with the normal rice floral organs, but with six normal stamens, a normal lodicule, a normal lemma and a normal palea. Each pistil has two to five ovaries, which separated or fused to one. There may be two to three stigmas on one style and three to five styles on one ovary. Two or more naked seeds instead of caryopsis could be produced in a single floret of the mutant plant.2 Genetic analyses of multi-pistil mutants: F2 populations were generated by the self-pollination of F] plants derived from the cross between mp3 (indicd) as the male parent and Xiushuill (japonicd) as the female parent. Single F| plants showed normal pistil. The pistil phenotypes appeared differently in F2 populations. Plants homozygous for mp3 were selected from F2 populations and used for linkage analysis of mp3. The F2 families that segregated mp3 were identified by the presence of multi-pistil. In these 2596 F2 families, 639 F2 plants that were homozygous for mp3 were identified, and the other 1937 plants were wild type. The ratio of wild-type and mutants was approximately 3:1 after x2 test, indicating the multi-pistil trait was controlled by a single recessive gene.3 The molecular mapping of mp3 gene: The mp3 gene has been located in the region between a SSR marker RM209 on one side and a CAPS marker LI on the other side in the short arm of chromosome 11, with a distance of 10.30 cM to RM209 and0.90 cM to LI. The single recessive gene which is termed as mp3 considering of the two reported genes mp1 and mp2 that have been located in the chromosome 1, 6.