高产、抗旱和耐盐选择对水稻产量相关性状的影响

Effect of Selection for High Yield,Drought and Salinity Tolerances on Yield-Related Traits in Rice(Oryza sativa L.)

水稻生产受到许多环境因素的胁迫,其中干旱和盐害是两大最重要的非生物逆境,培育抗旱和耐盐品种是减轻这两种逆境危害最经济有效的措施。利用籼型供体广恢122、Bg94-1和粳型供体原粳7号、沈农89366导入高产优质籼型品种丰矮占1号背景,创建BC3F5导入系群体,经目标性状筛选,以获得的2个高产抗旱导入系丰矮占1号/广恢122和丰矮占1号/原粳7号为亲本进行高产抗旱聚合,以高产耐盐导入系丰矮占1号/沈农89366和丰矮占1号/Bg94-1进行高产耐盐聚合。以聚合亲本为对照,在2个F2聚合群体中分别进行抗旱、耐盐、高产筛选,每个聚合群体分别获得30～42个不等的抗旱、耐盐和高产性状的极端个体,不同性状的选择强度变幅为8.3%～11.7%。3个目标性状极端选择后代在正常水田种植,其产量相关性状抽穗期、单株有效穗数、穗总粒数、穗实粒数、结实率、千粒重等均呈现明显的分离,各性状的变异方向因不同的选择群体和选择性状而异。在2个聚合组合的6个选择群体后代,有效穗数和每穗实粒数对单株产量的贡献最大,前者平均贡献率为18.5%,变幅为12.9%～27.4%,后者平均贡献率为13.1%,变幅为9.0%～21.2%。经过不同性状的交叉筛选,2个聚合组合的抗旱选择群体分别出现10.0%和36.7%耐盐的株系,其平均耐盐水平与耐盐选择群体相当,表明水稻抗旱和耐盐存在一定程度的遗传重叠。提出了利用回交导入系先进行抗旱、耐盐筛选,再进行产量选择和在此基础上对3个性状进一步聚合的高产抗旱和高产耐盐新品种培育策略。

Rice production is limited by many environmental factors, of which drought and salinity are the most important abiotic stresses which greatly constrain yield and planting area of rice. Development of drought and salinity tolerant （DT, ST） varieties is a most effective method to solve this problem. Using BC3F5 introgression populations derived from an elite indica variety Feng＇aizhan 1 （FAZ1） as the recurrent parent and indica varieties Guanghui 122, Bg 94-1, and japonica varieties Yuanjing 7 and Shennong 89366 as donor parents, two high yield （HY） lines with DT, FAZl/Guanghui 122 and FAZ1/Yuanjing 7, and two HY lines with ST, FAZ1/Shennong 89366 and FAZ1/Bg94-1, were selected and used for the pyramiding of HY and DT or ST. As compared with the pyramiding parents, DT, ST, and HY lines were selected from the two pyramiding F2 populations, getting 30--42 extreme DT, ST and HY individuals with selection intensity of 8.3%-11.7%, respectively. Under the irrigation condition, the selected populations with three target-trait all showed obvious segregations of yield-related traits including heading date, panicle number per plant, spikelet number per panicle, filled grain number per panicle, seed setting rate, and 1000-grain weight. Direc-tion of variation varied with the selected populations and the related traits. Among the six selected populations, the reproductive panicle number per plant and filled grain number per panicle had greatest contributions to yield with an average of 18.5% and a range of 12.9%-27.4% for the former an average of 13.1% and a range of 9.0%-21.2% for the latter. After intercross screening, around 10.0%-36.7% of ST lines were selected from the DT-selected populations of the two pyramiding crosses with an equivalent resistance levels as those ST-selected populations on the average, indicating that some genetic overlapping exists between DT and ST. The strategy of first screening against DT or ST then HY and further pyramiding of these three target traits from different donors is recommended for rice breeding for high yield with DT and ST.