[Genetic effects on seed traits in soybean].

The genetic effects of seed traits in soybean, including 100-seed weight, seed length, seed width, seed thickness, length/width, length/thickness and width/thickness, were analyzed using an incomplete diallel cross of eight varieties with its F1 and F2 populations. The results showed that the above seven traits were controlled by direct genetic effects of seed and affected to different extent of maternal and cytoplasmic effects simultaneously. Among the traits, the inheritance of 100-seed weight, seed length, length/width, length/thickness, and width/thickness were mainly controlled by cytoplasmic effects, while those of seed width and thickness were mainly by maternal effects. Both the seed direct heritabilities and the cytoplsmic heritabilities of 100-seed weight, seed length, length/width and width/thickness were medium-sized. The individual selection and seed selection of above four traits at late generation may create good results. The maternal heritabilities of seed width and thickness were pretty high. To increase these two traits, an individual maternal selection should be done at early generation. Our results showed that varieties P2 and P7 could be used as ideal parents for improvements of 100-seed weight, seed length/width, length/thickness and width/thickness, while varieties P1, P4 and P6 are the ideal parents for increasing seed length, width and thickness respectively.