大豆种间杂种高代品系与栽培品种双列杂交分析

本试验结果表明,种间杂种与丰产品种杂交 F_1代的杂种优势与亲本平均值呈显著正相关,多数性状优势的自交衰退现象不明显。所研究的性状中,单株产量具有较强的中亲优势率(25.23%);蛋白质含量也有一定中亲优势表现(3.07%)。但大部分性状不存在高亲优势,一般配合力可作为种间杂交育种亲本选配的参考指标。在研究的10个性状中,仅有单株荚数、单株粒数和百粒重对单株产量的通径系数达到显著水平。其中百粒重产对产量的决定系数远远高于前两者。因此,百粒重是种间杂种产量的第一决定因子,提高百粒重是选育产量突出品系的重要途径。

4x4 PARTIAL DIALLEL CROSSES BETWEEN LINES OF INTERSPECIFIC HYBRIDS AND CULTIVARS IN SOYBEANS——An Analysis of Heterotic Ability and Combining Ability on Yield Traits and Other Agronomic Traits

The experiment was comducted during the summer of 1986 at Northeast Agricultural College(NAC)Experimental Station in Harbin.Sixteen matings were made by crossing each of the four cultivars HAI 26,NAC 4,SAI 4,and XHD with four interspecific hybrids lines Wild-Ⅰ,Wild-Ⅱ,Semi-Ⅰand Semi-Ⅱ.F_1 population of each cross was grown in a randomized complete block design with two replications.Each entry consisted of a single3-meter row.Plant-to-plant distance was maintained at 10 cm.The parents and F_2 populations were also grown in the same field.At maturity,ten plants of each row were evaluated for growth period,plant height,number of branches,number of nodes on main stem,pods no.per plant,seed number per plant,seed weight per plant,100-seed weight,oil and protein content.The combining ability,path-coefficient as well as heterosis were worked out accoding to the methods reported by Liu(1984).In this research an attempt was made to develope soybean varieties having both high protein content and high yield through im- proving small seed size donated by interspecific hybrid lines.The main results were as follows: 1.The heterosis in F_1 generation was significantly correlated with trait means of parents. There was no obvious inbreeding depression for most characters tested except for yield per plant and nodes no.per plant.The F_1midparent heterosis in yield per plant was greater than that in any other characters with a value of 25.23%,and in protien content it also reached to 3.07%.On the contrary,the performance of highparent heterosis was less significant on most traits included. 2.GCA effect for most traits was more significant than SCA effeet,except for nodes no. per plant and yield per plant.Therefore cultivatcd varieties with high GCA effect in yield traits and quality traits would be appropriate to be used as cultivated parents in interspecific cross. 3.According to the results of correlation and path analysis of ten traits,only the path coefficients of 100-seed weight,seed numbers per plant and nodes no.per plant to yield per plant were significant.Among the above traits,100-seed weight possesed thc highest deter- mining coefficient to yield per plant.It was suggested that the key of improving low yield would be the increase of 100-seed weight in interspecific hybrid population of soybean.