杂草稻资源表型多样性分析及综合评价研究

Phenotypic Diversity Analysis and Comprehensive Evaluation of Weedy Rice Germplasm

杂草稻是生长形态与栽培稻相似,而稻米质量、落粒性和休眠性等性状不符合栽培稻生产需求的一类杂草。江苏省是我国杂草稻危害最严重的省份之一,大量研究主要集中在杂草稻的起源、性状和防控,杂草稻群体作为种质资源用于栽培稻品种改良尚无系统研究。丰富的遗传多样性和优良种质资源是栽培稻育种以及品种改良中最重要的物质基础,本研究收集21个江苏省不同地区的杂草稻群体、6个栽培稻品种和2个杂草稻对照群体为材料,通过在海南同质园种植,测定18个表型性状,分析其性状的多样性,并进行相关性分析、主成分分析、聚类分析和综合评价研究。结果表明:杂草稻的齐穗期和齐花期均明显早于栽培稻,杂草稻的实粒数和总粒数均较优于栽培稻,杂草稻资源群体表型性状变异系数为2.99%~196.29%,多样性指数为0.27~2.06,多样性指数最高的是结实率,其次为实粒数、剑叶长/宽和总粒数。相关性分析表明,18个表型性状之间大部分存在显著或极显著相关,始穗期和始花期与株高、穗长、剑叶长宽比、总粒数、实粒数、千粒重、分蘖数间均呈极显著正相关,千粒重与穗长、剑叶长宽比、分蘖数、始穗期、始花期呈极显著正相关。主成分分析将18个表型性状集中在累计贡献率为70.57%的6个主成份,其中正相关影响最大的性状是杂草稻的始穗期、始花期、齐穗期、齐花期、总粒数、实粒数等性状。聚类分析将23个杂草稻群体在欧式距离为5时分为5大类。18个指标综合评价D值>0.68的有3个群体,其中,来自南通如皋WJ-NJ1的D值最高(0.715),其次是来自常州金坛WJ-CZ1(0.698)和盐城市辖区WJ-YC2(0.682)。本研究为杂草稻种质资源在未来的辅助育种以及栽培稻品种改良等方面提供了重要的理论依据。

Weedy rice is a weed similar to cultivated rice in growth form,but does not meet the requirements of culti-vated rice production in rice quality,grain setting and dormancy.Jiangsu province is one of the provinces with the most serious damage to weedy rice in China. Many studies have focused on the origin, characters and control of weedy rice. There has no systematic study on weedy rice population as germplasm resources for cultivar improvement. Rich genetic diversity and excellent germplasm resources are the most important material basis for cultivated rice breeding and vari-ety improvement. In the study, 21 weedy rice populations in different regions of Jiangsu Province, six cultivated rice varieties and two weedy rice populations as the control were planted in a Hainan homogeneous garden, and the diversity of 18 phenotypic traits was analyzed. Correlation analysis, principal component analysis, cluster analysis and compre-hensive evaluation analysis were performed. The full panicle stage and flowering stage of weedy rice were significantly earlier than that of cultivated rice, and the rice grain number and total grain number of the weedy rice were relatively better than that of the cultivated rice. The phenotypic traits variation coefficient of the weedy rice resources group was 2.99%‒196.29%, and the diversity index was 0.27‒2.06, with the highest diversity index for seed setting rate, followed by solid grain number, sword leaf length/width, and total grain number. The beginning stage of heading and flowering had extremely significant positive relation with plant height, spike length, sword leaf aspect ratio, total grain number, actual grain number, 1000 grain weight and tillering number. 1000 grain weight had extremely significant positive rela-tion with tiller number, spike length, sword leaf aspect ratio, tillering number, beginning stage of heading and flowering. Cumulative contribution 70.57% was from six principal components, including first heading stage, first flowering stage, full heading stage, full flowering stage, total grain number and full grain number. The 23 weedy rice populations were divided into five categories when the Euclidean distance was 5. There were three populations with D value >0.68 in the comprehensive evaluation of the18 indicators, with the D value of WJ-NJ1 from Rugao, Nantong the highest (0.715), followed by WJ-CZ1 from Jintan, Changzhou (0.698) and WJ-YC2 from Yancheng Municipal District (0.682). This study would provide an important theoretical basis for weedy rice germplasm resources in future assisted breeding and improvement of cultivated rice varieties.