吉林省不同年代育成大豆品种根瘤数量、鲜重和体积的变化

对吉林省1923年以来育成的20个主要栽培大豆品种不同生育期根瘤数量、根瘤鲜重和根瘤体积的变化进行了比较研究。结果表明，大豆根瘤数量、根瘤鲜重和根瘤体积在四叶期（V4）根瘤形成很少，品种间也无差异，盛花期（R2）最大，结荚期（R4）略有下降，鼓粒期（R6）期最低。R2期、R4期大豆根瘤数量、根瘤鲜重和根瘤体积与育成年代和产量呈正相关，其中R2期与育成年代和产量关系最为密切，R6期呈负相关，但不显著。现代品种根瘤数量、根瘤鲜重和根瘤体积在心期均呈下降变化，而老品种根瘤数量、根瘤鲜重和根瘤体积在R6期则表现增加的变化趋势。

Nodule number fresh weight and volume of soybean cultivars over the years in Jifin province

In order to evaluate the changes of nitrogen fixation characteristics in soybean cultivars during the genetic improvement, a comparative study was made in nodule number, fresh weight and volume with 20 soybean eultivars released from 1923 to 2005. The results showed nodule number, fresh weight and volume were low at fourth leaf stage （V4） , then increased at R2 （flowering） and R4 （pod growth） stages. At R6 （seed filling）, nodule number, fresh weight and volume were much lower in modern cultivars compare to traditional ones. Nodule number, fresh weight and volume showed significant positive correlation with yield at R2 stage. Our results indicated that genetic improvement of soybean cultivars increased nodule number, fresh weight and volume along with the year of release. Nodule number ,fresh weight and volume at RE stage had greater influence in yield selection indexes in soybean breeding.