籼型杂交稻恢复系动态株型与光能利用率评价

Evaluation of Dynamic Plant Type and Radiation Use Efficiency of indica Hybrid Rice Restorer Lines

【目的】理想株型是水稻高产稳产的前提。本研究拟对不同年代育成的籼型三系杂交稻恢复系动态株型与光能利用效率进行综合评价,探讨恢复系光能高效利用的理想动态株型特征,为提高光能高效利用的高产稳产杂交稻育种效率提供理论依据。【方法】以明恢63、明恢82、蜀恢527、广恢998、广恢122、广恢128、广恢308和桂99等8个大面积应用的籼型杂交稻恢复系为供试材料,在华南生态条件下考查了其分蘖、叶面积指数(LAI)、透光率、叶片大小与开张角、叶色(SPAD值)等性状的动态变化,以及抽穗期光合速率、生育期、产量相关性状和光能利用率(RUE)等指标。【结果】各恢复系之间在株型动态变化、产量和光能利用率(RUE)等方面存在较大差异。良好的动态株型与光能利用率密切相关,最为接近华南生态条件下理想动态株型的广恢998和广恢308,光能利用率最高。根据聚类分析,广恢998、广恢308和明恢82属于光能高效利用的类群Ⅰ。其他恢复系归为类群Ⅱ。最后,根据华南的光温生态特点,提出了水稻光能高效利用的理想动态株型模式及育种选择关键指标:1)移栽后分蘖和叶面积发展快,LAI达到1.0的时间≤27 d;茎蘖数达到峰值所需时间≤38 d,分蘖力中等,最高茎蘖数≤600苗/m^(2);2)前期窄叶长披,移栽后15 d顶部3片完全叶平均长度为37 cm,平均宽度≤0.9 cm,开张角度≥80°;后期叶片窄直,抽穗后20 d顶部倒3叶平均开张角≤65°,平均长度为43 cm,平均宽度≤1.3 cm,属于中叶型,有利于后期群体通风透光;3)后期叶片转色好,不早衰,SPAD值维持在35~40,抽穗前20 d至抽穗后20 d之间的叶片SPAD值降幅≤13%;普通栽培条件下平均每穗总粒数180粒左右,有效穗数300穗/m^(2)以上,结实率≥85%。【结论】广恢998和广恢308具有较为理想的动态株型和较高RUE,利用其配制的杂交稻天优998、博优998和五优308等连续多年成为我国华南稻区主导品种和国家与省级区试对照品种。说明通过选育光能高效利用的理想动态株型恢复系,是组配选育高产稳产杂交稻行之有效的重要途径。

【Objective】A restorer(R)line with ideal dynamic plant type(DPT)is the premise of hybrid rice breeding with high and stable yield.The purpose of this study is to evaluate the DPT and radiation use efficiency(RUE)of the R lines bred in different periods,and investigate the characteristics of ideal DPT for efficient utilization of light energy,and lay a theoretical basis for breeding of high-yielding hybrid rice with high RUE.【Method】A field experiment was conducted under the ecological conditions of South China with eight widely and commercially used R lines of indica hybrid rice Minghui 63,Minghui 82,Shuhui 527,Guanghui 998,Guanghui 308,Guanghui 128,Guanghui 122 and Gui 99 as material.The dynamic changes of tiller number,leaf area index(LAI),light transmittance of the population,leaf size,leaf angle and leaf color(SPAD value),as well as the photosynthetic rate in the heading stage,heading date,yield related traits and RUE were measured.【Result】There existed significant difference in dynamic changes of plant type,yield and RUE among the restorer lines.Ideal DPT was closely related to RUE.With the most ideal DPT under the ecological conditions of South China,Guanghui 998,Guanghui 308 and Minghui 82 had the highest RUE.According to the cluster analysis,Guanghui 998,Guanghui 308 and Minghui 82 were classified into ClusterⅠwith high RUE,and the other five restorers fallen into ClusterⅡ.Finally,based on the ecological conditions in South China,an ideal DPT model of rice for efficient utilization of light energy was proposed.And the key indicators of breeding and selection were as follows:a)The tiller number and leaf area increased rapidly after transplanting;it cost less than 27 d to make LAI≥1.0,and less than 38 d to peak tiller number with moderate tillering ability,and the highest tiller number less than 600/m^(2);b)Narrow,droopy and long leaves in the early stage.On 15 days after transplanting,the average length,width and opening angle of the top three complete leaves were about 37 cm,≤0.9 cm and≥80°,respectively;narrow and straight leaf in late stage;on the 20th day after heading,the average opening angle,length and width of the top three leaves were≤65°,43 cm and≤1.3 cm,respectively,belonging to medium sized leaf type.c)In the late stage,the leaf color turned from green to orange or yellowish gradually without premature senescence.The SPAD values ranged from 35 to 40,the decrease of SPAD value between 20 days before heading and 20 days after heading was less than 13%;the average number of grains per panicle was about 180 with the number of effective panicles more than 300/m^(2) and seed setting rate≥85%.【Conclusion】Guanghui 998 and Guanghui 308 have better DPT and higher RUE.The hybrid rice Tianyou 998,Boyou 998 and Wuyou 308 derived from these restor lines,have become the leading rice varieties for many years in southern China.Breeding hybrid rice with high and stable yield through the developing of R lines with ideal DPT and high RUE is an effective and important way.