Genetic Analysis And Molecular Mapping Of A New Dwarf Mutant D63(t) In Rice

A new dwarf mutant, belong to dn dwarf type with dark-green and low fertility was identified from DH population derived from Chunjiang 06/TN1. Allelic test with d1, d2 and d11 mutant respectively demonstrated d63(t) is nonallelic to them with normal plant height of F₁ and 9:7 segregation rate of F₂. The result ofα-amylase induction by GA3 suggested it was possibly associated with GA signal transduction. Plant height of F₁ was normal and segregation rate of F₂ coincided with 3:1 byχ² test testified d63(t) is controlled by single recessive gene. We hybridized d63(t) with Japonica rice variety ZhongHua 11 and Indica rice variety 9311, ZheFu 802 respectively for DNA polymorphism.Polymorphism selection by 534 SSR showed that high polymorphism was detected on chromosome 1 between d63(t) and Indica rice. Thereafter, combination of d63(t) and 9311, whose genome has been sequenced, was utilized as a mapping population. Tightly linked SSR marker RM1 was found following by 24 new STS and SSR markers designed based on published whole genome sequence of Indica (http://www.rice.genomics.org.cn) and Japonica (http://rg-p.dna.affrc.go.jp) rice. D63(t) gene was finally mapped on short arm of chromosome 1 linked with RM490 (1.45 cM) and dw16 (1.65 cM) covering 991 kb of 10 BAC via 242 recessive plant genotyping. The mapping result suggests that D63(t) be located at different locus with two identified dwarf genes located in this region, D2 and D18.