野生大豆抗蚜性的利用研究 Ⅰ 栽培大豆和野生大豆杂交F_2代的抗蚜性

STUDY ON THE UTILIZATION OF APHID RESISTANT CHARACTER IN WILD SOYBEAN Ⅰ. APHID RESISTANT PERFORMANCE OF F_2 GENERATION FROM CROSSES BETWEEN CULTIVATED AND WILD SOYBEANS

以3份栽培大豆(Clycine max)与2份野生抗蚜大豆(G.soja)材料杂交,用人二接虫鉴定的方法研究了杂交F_2代的抗蚜性分离特点和抗性遗传规律。研究结果表明,F_2代单株抗蚜性呈连续性单峰分布,分布高峰倾向于感虫的栽培亲本。绝大多数F_2单株都表现为感虫或高感,3个杂交组合分离出的抗蚜单株约占F_2群体的7.2～10.2％。有2个组合的抗蚜性分离非常适合2对主效基因控制抗蚜性的假设(P>0.50),而另一组合的抗蚜性分离也倾向于2对基因的假设,上述结果说明,抗蚜性可能是由2个独立的隐性基因和一些微效基因共同控制的。如果将抗蚜性视为数量性状,根据F_2和亲本方差估计的广义遗传力,介于85.5～97.0％之间。尽管抗蚜性的遗传力较高,由于F_2代抗性个体很少,而野生大豆又带有许多难以克服的不利性状,因此,选择的世代应适当推迟。由于抗虫性属于隐性,在利用回交法转移野生大豆的抗蚜基因时,为了避免抗性基因的丢失,每轮选择的回交次数不宜过多。

Three crosses between 3 cultivated(G. max)and 2 aphid resistant wild soybean(G. soja)lines were made to study the inheritance of resistance and segregation patterns in F2 generation with artificial inoculation technique. The aphid resistance of the F2 plants showed continuous mono-peek distributions which inclined towards the susceptible parents. Most of the F2 plants were susceptible or highly susceptible. Only about 7. 2 to 10. 2% of the F2 plants were resistant to soybean aphid. The segregations in 2 out of the 3 crosses studied fitted the hypothesis that there are 2 independent gene pairs controling the aphid resistant character of the wild soybean lines (P> 0. 50). The segregation of the other cross also tended to fit the 2 major gene model. These results indicated that the aphid resistance of the wild parents might be controled by 2 independent recessive genes and some other minor genes. Supposing that the aphid resistant character was quantitatively inherited, the broad sense heritability estimated from the variances of parents' and F2 populations was between 85. 5 and 97.0% . Despite of the high heritability of aphid resistance , It is recommended that the selection of resistance should be postponed to later generations such as F3 or F4, because of the scarcity of resistant plants and the undesired wild soybean characters in F2 generation. Because the aphid resistant genes may be recessively inherited, the number of backcrosses made in each cycle of selection should be limited to avoid the resistant genes being lost.