水稻分蘖角基因TAC1的育种应用价值分析

【目的】分蘖角度是水稻重要株型性状,合理的分蘖角度是培育理想株型、达到高产育种的一个关键因素。【方法】以控制水稻分蘖角度增大的显性主效数量基因TAC1为研究对象,构建不同品种背景下的TAC1近等基因系,通过单本栽插、多本栽插/高产栽培以及纹枯病菌接种鉴定,分析TAC1对其他农艺性状、纹枯病抗性、产量及品质的影响。【结果】同一背景近等基因系之间比较,TAC1使水稻品系分蘖角度增加,有利于减轻纹枯病危害,对其他农艺性状无不利影响。在高产栽培条件下,不同背景TAC1系有效穗数均多于tac1系;籼稻特青背景下,TAC1系结实率、千粒重及单株产量均高于tac1系;美国稻Lemont背景下,TAC1系结实率、千粒重及单株产量均低于tac1系;粳稻武陵粳1号、镇稻88背景下,TAC1系结实率和千粒重均略低于tac1系,单株产量略高于tac1系,差异不显著。加工及外观品质方面,特青TAC1系优于tac1系,武陵粳1号、镇稻88以及Lemont背景TAC1系较tac1系有劣化趋势,差异均不显著。【结论】叶片较长的籼稻品种,适宜的分蘖角度范围较窄,叶片较小的粳稻品种,适宜的分蘖角度范围较宽。适当增加水稻品种的分蘖角度,有利于减轻纹枯病危害。TAC1可用于株型紧凑型籼稻品种及粳稻品种的株型改良。

Breeding Potential of Rice TAC1 Gene for Tiller Angle

【Objective】Rice tiller angle is an important plant-type trait. The appropriate tiller angle is generally a critical factor in developing ideal-type high-yielding rice variety. 【Methods】Effects of tiller angle controlling gene TAC1 on agronomic traits, sheath blight resistance, grain yield and quality were investigated under conditions of one-plant one-point and multi-plants one-point transplantation by using four pairs of near isogenic lines(NILs) at TAC1 gene.【Results】TAC1 increased rice tiller angle in all the genetic backgrounds tested, which is beneficial for reducing adverse impacts of sheath blight, without affecting other agronomical traits. Under high-yielding cultivation condition of multi-plant one-point transplantation, numbers of effective panicles in all the NILs with TAC1 were apparently higher than those of corresponding NILs with tac1. In the background of indica rice Teqing, the seed-setting rate, 1000-grain weight and plant yield of Teqing-TAC1 line were all higher than those of Teqing-tac1 line; however, the reverse results were obtained in the background of Lemont. In backgrounds of Wulingjing 1 and Zhendao 88, NILs with TAC1 gene displayed slightly grain yield than those with tac1 gene. The grain processing and appearance qualities of Teqing-TAC1 line were slightly improved compared to the corresponding control, while other TAC1-harboring NILs showed just the reverse with statistically insignificant difference. 【Conclusions】The indica rice with long leaf has a narrow range of appropriate tiller angles but for japonica rice with short leaf, the range is wider. Increasing rice tiller angle to an extent is beneficial for reducing sheath blight influence. TAC1 improves the plant type of japonica rice as well as the compact type indica rice.