克服大豆种间杂种蔓生、小粒等不良性状技术的初步研究

A PRELIMINARY STUDY ON OVERCOMING VINY AND SMALL SIZE SEED HABIT OF SOYBEAN INTERSPECIFIC HYBRIDS

本试验利用结荚习性不同的3个栽培大豆(G.max)作母本,以株高不同的2个野生大豆(G.soja)和2个半野生大豆(G.gracilis)作父本配制的12个杂交组合和8个回交组合,研究克服种间杂种蔓生、小粒等不良性状的技术。研究结果表明:选用植株较矮、主茎较粗、百粒重较大的有限、亚有限性栽培种作母本;选用植株较矮、百粒重较大的野生种作父本将有利于克服种间杂种蔓生、小粒等不良性状;野生亲本的选择似乎更为重要。从克服种间杂种蔓生、小粒等不良性状来看,选用半野生大豆作亲本更为有效。只有从直立、半直立植株的后代中才有可能分离出稳定的直立型材料。百粒重的遗传进度较小,对其进行选择似乎效果不明显。在F_3代进行选择性回交可以大幅度提高其后代直立、半直立型植株的分离频率和百粒重。只要亲本选配适当,仅需一次回交即可克服种间杂种蔓生、小粒的不良性状。我们从一次选择性回交的后代中已获得栽培型、百粒重20克以上,产量较高的优良品系。

Progenies from 12 crosses and 8 backcrosses were used in this experiment. 12 crosses were made with three cultivated soybean having different inflorescence and two wild soybean (G. soja) and two semiwild soybeans ( G. gracilis) as parents. The results showed that, in the interspecific cross, choosing the cultivated genotype with determinate and semi-determinate inflorescence, lower plant height, thick main stem and higher 100-seed weight: as female parentage, choosing the wild genotype with lower plant height, higher 100-seed weight as the male parentage is feasible for overvoming the viny and small size seed habit. It seems that the choosing of wild parent is more im-potant than that of cultivated soybean, It is more effective to choose the semi -wild soybean as the parents in interspecific cross. The stable erect line only segregated out from the erect and semi -erect progenitor plants. The genetic advance of 100 -seed weight was smaller in F2 generation. It seems that the selection of 100-seed weight is ineffective in interspecific cross. The weight of 100 -seed and the range oi erect and semi -erect plant can be increased significantly, if backcross was made in F3 generation. The characters of viny and small seed can be overcome by backcross only once, if the parents are suitable. We have obtained some lines with cultivated type, high yield and 100 -seed weight over 20 g. through interspacific crosses.