水稻抗稻瘟病基因Pi-d（t）^1、Pi-b、Pi-tα^2的聚合及分子标记选择

冈46B(G46B)是水稻生产应用中的一个农艺性状十分优良的保持系，其主要的缺陷是稻瘟病抗性较弱，通过对地谷，BL-1，Pi-4号等三个分别含抗病基因Pi-d(t)^1、Pi-b、Pi-tα^2的稻瘟病抗性材料与G46B聚合杂交，并利用抗病基因连锁的分子标记对杂交后代进行辅助选择，在聚合杂交的F2代及B1C1代群体中共获得了15株含Pi-d(t)^1、Pi-b、Pi-tα^2等三个抗稻瘟病基因的材料，其可能的基因型分别为：三基因杂合体Pi-d(t)^1pi-d(t)^1，Pi-bpi-b／Pi-tα^2 pi-tα^2 4株，双基因杂合体10株，其中Pi-d(t)^1Pi-d(t)^1／Pi-bpi-b／Pi-tα^2pi-tα^2 6株，Pi-d(t)^1pi-d(t)^1／Pi-bpi-b／Pi-tα^2Pi-tα^2 3株，Pi-d(t)^1pi-d(t)^1，Pi-bPi-6，Pi-tα^2 pi-tα^2 1株，双基因纯合体Pi-d(t)^1Pi-d(t)^1/Pi-bpi-b/Pi-tα^2Pi-tα^2仅1株，这一研究结果为进一步改良G46B的稻瘟病抗性奠定了基础，同时这一研究结果表明利用分子标记可快速、有效地实现多个抗病基因的聚合，大大提高水稻抗病育种的效率。

Marker-assisted selection and pyramiding for three blast resistance genes, Pi-d(t)1, Pi-b, Pi-ta2, in rice]

G46B is a promising holding line used for three lines breeding strategy in hybrid rice, but it is susceptible to blast disease caused by Pyricularia grisea. To improve its blast resistance, three rice varieties, Digu, BL 1, and Pi 4, with blast resistance genes, Pi d(t) 1, Pi b, and Pi ta 2, respectively, were used to be crossed with G46B, and 15 plants with these three blast resistance genes, Pi d(t) 1, Pi b, and Pi ta 2, were selected from their F2 and B1C1 populations via a marker aided crossing procedure. Among them, four plants were heterozygotes in the three resistance genes, with the genotype of Pi d(t) 1pi d(t) 1/Pi bpi b/ Pi ta 2pi ta 2; ten plants were heterozygotes in two of the three resistance genes, of which six with the genotype of Pi d(t) 1Pi d(t) 1/Pi bpi b/Pi ta 2pi ta 2, three with the genotype of Pi d(t) 1pi d(t) 1/Pi bpi b/Pi ta 2Pi ta 2, and one with the genotype of Pi d(t) 1pi d(t) 1/Pi bPi b/Pi ta 2pi ta 2; and only one plant was homozygote in two of the three resistance genes with the genotype of Pi d(t) 1Pi d(t) 1/Pi bpi b/Pi ta 2Pi ta 2 These results demonstrate the capacity of maker assisted selection (MAS) in gene pyramiding for rice blast resistance and its enhancement for the efficiency in rice resistance breeding.