粳稻新老品种株型性状比较

选用日本、韩国、中国的粳稻品种30个，将1990年及以前育成的品种称为老品种，1991年及以后的品种称为新品种。比较新老品种株型性状的变化及其对产量的效应。结果表明：(1)新品种比老品种株高低，穗角小，单株有效穗数少，每穗总粒数多，着粒密度大；新品种比老品种倒2叶基角大，倒3叶基角和张角小，倒3叶叶长短。(2)新老品种的10穴产量，穗总粒数，穗角及着粒密度差异极显，新老品种剑叶、倒2叶和倒3叶的叶宽差异极显。(3)根据通径系数，老品种中穗总粒数、单株有效穗数对产量的直接作用较大；新品种中经济系数、穗总粒数对产量的直接效应较大。新老品种中着粒密度对产量的间接效应总和都为最大。新老品种的倒2叶宽对产量的直接效应较大。老品种的剑叶宽和剑叶基角对产量的间接效应总和较大；新品种的倒3叶宽和倒3叶基角对产量的间接效应总和较大。

Comparison of plant type traits between new and old varieties in japonica rice (Oryza sativa L.)

Changes of plant type traits between old and new varieties and the effect of these changes on yield were studied by using thirty japonica rice varieties selected from Japan,Korean and China.We referred the varieties bred in or before 1990 as old and those bred in or after 1991 as new varieties.The results were as follow:(1)The plant height was lower,panicle angle was smaller,number of panicles was fewer,total spikelets per panicle and spikelets per cm panicle were more in new varieties than that in old varieties.In leaf type characters,the basic angle of 2nd leaf from top was bigger,the basic angle and stretch angle of 3rd leaf from top were smaller,and the length of 3rd leaf from top was shorter in new varieties than that in old varieties.(2)The yield of 10 hills,grains per panicle,panicle angle,spikelets per cm panicle and the width of 1st leaf,2nd leaf and 3rd leaf from top had significant difference between new and old varieties.(3)Judged by path coefficients,direct effect of grains per panicle and panicle number on yield is important in old varieties,and direct effect of harvest index and panicle number on yield is important in new varieties;indirect effect of spikelets density upon yield is important in both new and old varieties.In leaf type characters direct effect of the width of 2nd leaf from top on yield is important in both new and old varieties.Indirect effect of the width of top leaf and top leaf basic angle upon yield is important in old varieties,and indirect effect of the width and basic angle of 3rd leaf from top upon yield is significant in new varieties.