甘蓝型油菜(Brassica napus L.)千粒重性状遗传体系分析

Analysis of Genetic System of 1 000 seed Weight in Brassica napus L

通过遗传差异较大的 2个甘蓝型油菜 (BrassicanapusL )纯系亲本组合 (HSTC14×宁油 7号 )衍生后代的世代家系群体分析 ,应用主基因 +多基因家系世代联合分离分析方法研究油菜千粒重的遗传体系。结果表明 ,甘蓝型油菜HSTC14×宁油 7号组合千粒重遗传体系系由一对主基因 +多基因构成 ,主基因中只有加性效应 (d =0 10 6 2 ) ,不存在显性效应 ;多基因存在加性 ([d]=0 2 2 2 8)和显性效应 ,但显性效应为负值 ([h]=- 0 2 80 0 )。表明该组合千粒重主要由主基因加性效应和多基因效应决定 ,但无杂种优势。F2∶3家系群体主基因遗传力为 83 39% ,多基因遗传力为 11 71%。HSTC14×宁油 7号组合千粒重的改良可能受主基因无显性效应 ,多基因显性效应为负值的制约。

Genetic system of 1 000 seed weight in Brassica napus L was studied by means of a joint segregation analysis in a multi family generations (P 1,F 1,P 2,B 1∶2 ,B 2∶2 and F 2∶3 ) of HSTC14 × Ningyou 7 Results showed that genetic system of 1 000 seed weight of HSTC14 × Ningyou 7 was consisted of one pair of major gene plus polygenes An additive effect( d =0 1062) was found only in major genes of the genetic system Effect of polygenes acted in the manner of additive([ d ]=0 2228) as well as dominant with a negative value([ h ]=-0 2800) It indicated that there was no heterosis for 1 000 seed weight found in the cross because of no dominant effect found in major genes that played an important role in the genetic system of 1 000 seed weight Hereditability of major gene ( h 2 mg ) in F 2∶3 population was 83 39%,and that of poly gene ( h 2 pg ) was 11 71% It seems to be that progress of improvement of 1 000 seed weight in the cross of HSTC14×Ningyou 7 is hindered by no dominant effect found in major gene and the negative value of dominant effect found in poly gene