栽培稻种间杂交改良云南粳稻品种研究

为引入非洲栽培稻的有利基因以丰富云南粳稻的遗传基础以达到培育高产、抗病、抗逆云南粳稻品种的目的，利用179个非洲栽培稻品种作母本与6个云南粳稻杂交，并用相应父本回交后形成F1、BC1F1、BC2F1、BC2F2群体，同时对滇粳优1号作轮回亲本的组合在BC2F1中每组合随机用5~10株回交至BC3F1。研究表明，F1及BC1F1的自交结实率为0，种间杂种不育是非洲栽培稻与亚洲栽培稻种间杂交最主要的生殖障碍；但回交至BC2F1自交结实率即达到7.9％， BC3F1的平均结实率为14.6％，在BC2F1选结实率在10％以上的植株自交1次，BC2F2的结实率即为42.8%，变幅15%~80%；表明杂种不育模式符合“单位点孢子体 配子体互作不育”。在BC2F2群体中，10.7％的组合的综合表现优于轮回亲本。大规模育种实践表明，通过两次回交，再自交2~3代，种间杂种不育的障碍基本可得到克服，并可引入非洲栽培稻的有利基因。

Interspecific Hybridization of Cultivated Rice for Breeding japonica Rice in Yunnan Province

In order to explore the role and feasibility of interspecific hybridization of cultivated rice for breeding japonica rice, especially temperate japonican rice, 179 accessions of Oryza glaberrima Steud. were pollinated with six varieties of O. sativa L.subsp. japonica from Yunnan, and backcrossed with respective male parents to form F₁, BC₁F₁, BC ₂F ₁, BC₂F₂ and BC₃F₁ populations. Spikelet fertility of F₁, BC₁F₁, BC ₂F ₁, BC₂F₂ , BC₃F₁, and phenotypic acceptability (PAcp) at maturity compared to recurrent parents on BC₂F₂ were investigated. All F₁ and BC₁F₁ progenies were highly sterile. BC₂F₁ gave 7.9% spikelet fertility. When plants of BC 2F 1 with over 10% spikelet fertility were selected, BC₂F₂ showed 42.8% spikelet fertility, ranging from 15% to 80%. BC₃F ₁′s spikelet fertility was 14.6%. It was notable that 10.7% of combinations gave higher PAcp than their recurrent parents in BC₂F₂. It suggested that hybrid sterility was the most serious reproductive barrier to introgress useful genes from O. glaberrima to O. sativa or utilization of interspecific heterosis, and the genetic model of hybrid sterility was mainly “one locus sporo-gametaphytic interaction”. But fertile progeny with O. glaberrima′s traits could be obtained after two or three times of backcrossing, selection, and inbreeding. Therefore, O. glaberrima is the first choice of interspecific hybridization breeding or introgression of useful genes for O. sativa among the wild relatives of rice from the view of breeding, origin, evolution, and genetics.