Length Detection Of Substitutive Fragments In Rice NILs And Fine Mapping For Wide Compatibility Gene S₅～n

Rice wide compatibility (WC) gene S₅ⁿ from various original wide compatibility cultivars (02428, Dular, Huanuo, Woaiga, Cpslo17, Ketan Nangka) were introduced into typical indica cultivar Nanjing 11 and japonica cultivar Balilla to establish NILs. Molecular markers were employed to survey the length of substitutive fragments in some NILs. Based on the survey results, the wide compatibility gene S₅ⁿ was further located between molecular makers J13 and J26. The physical position of gene C(chromogen for anthocyanin) and its physical distance to S₅ⁿ was definited. A preliminary discussion was taken on differences of substitutive fragments corresponding to heading stage and plant height among NILs. And the results were as follows.(1) The average lengths of substitutive fragments in NILs (02428→N11, Dular→N11, 02428→Ba, Dular→Ba) were 4218kb, 5005kb, 5235kb, 5103kb, respectively.(2) Five recombined NILs between molecular markers J13 to J26 were found. The distance of the 2 markers is 13 kb, WC gene locus was limited in this region. Furtherly, gene prediction was taken in this region by FGENESH, and only two ORFs (open reading frame) were detected on each chain, respectively. The gene on negative chain encoded a putative protein, while the other encoded eukaryote aspartate proteinase(Asp). The latter was of great possibility to be the candidate gene for WC gene. The result was helpful to clone S₅ⁿ and MAS of rice.(3) According to the detection results of substitutive fragments, C gene was limited between RM19556 and RM 253, a 188kb region, which was 427±94kb distant from S₅ⁿ.(4) The recombination between RM20012 and RM200172 was related to plant height. And the distance between them was about 4.8Mb. Some genes related to plant height might lie in this region.