大豆超早熟育种问题的研究

本文通过对大豆早熟性基因源的鉴定分析,极早熟品种在个体发育中生育期与各生育阶段的相关性测定以及早熟性遗传变异规律的研究,结合超早熟育种实践,指出超早熟育种首要问题是自不同生态区最广泛地搜集血缘关系较远的极早熟或早熟品种(000或00成熟期组)。经系统鉴定,筛选双亲生育日数差值小、花期短、鼓粒快、株体繁茂、中日性、耐低温和极早熟种质资源作亲本。以极早熟、丰产、杭病品种间杂交为最佳组合方式,通过有性杂交获得早熟性基因累加超亲遗传个体,从而创造更早熟的杂交后代材料,于F_2和F_3世代,以早熟、抗病性为主进行混合选择,严格淘汰晚熟、感病组合及单株。F_4世代以丰产性为主,从早熟,抗病后代群体中大量选拔丰产单株,下年进行株系鉴定。并指出,50°N高寒地区建立选育基地,在当地生态条件下进行选育,更有利于超早熟品种的育成。

BREEDING FOR SUPER-EARLY RIPENING SOYBEAN CULTIVARS

The development of early soybean cultivars had already been effective to promote soybean production toward the high latitude regions.The objective of the present study is to discuss the breeding objectives of super-early soybean cultivars,the indentification of gene source of early maturation as crossing parents,method of parental combination,heredity of early maturity,and method of selection for super-ealiness. The super early soybean cultivars to be developed for high latitude and short growing season regions should be photoperiodically day-neutral,with growth period less than 80 days,adaptable to conditions of lower temperature (≥10℃)and accumulated temperature around 1,600—1,700℃,with fast and vi- gorous vegetative growth,stiff stem,short pod-filling period,disease resis- tance,good seed quality.and high yield. For breeding of super-early soybean cultivars,early maturing germplasms from diverse geographical origination should be chosen as crossing parents,both parents should be extremely early type(000 maturity group),and parents used should alse be with short synchronous period of vegetation and reproduction (R_1—R_6)and short reproductive stage(R_5—R_8). The best parental combinatiot seems to be adapted extremely early×exotic extremely early(000×000),or adapted early and high yield×exotic early and high yield. The mood of inheritance of earliness of soybean is that growth period of F_1 is either the mean of the two parents or similar to one of the two parents. The of segreggtion of earliness in F_2 is usually normal distribution,and the mean of growth period is also equal to the mean of the two parents.The di- stribution of segregation of earliness in F_2 is usually normal distribution,and the mean of growth period is also equal to the mean of the two parents.The distribution of segregation of earlyness in F_3 is almost the same as that of F_2 but with larger segregation range.It means therefore that the gene effect of ear- liness of soybean is mainly additive. In the procedure of selection,earliness should be taken as the main item for selection in F_2 and F_3,with mass selection as the selection method.In F_4, high yield should be the main item for selection and superior individual plants selected.Plant progeny row test should be carried out in F_5.