Dissection of heritability and genetic variance components for yield traits in tropical and temperate maize populations

Chinese. 评估2个热带群体和7个温带群体的育种价值，并在这些群体之间寻找新的杂种优势模式，为利用这些种质提供有用的科学信息。采用9个群体的双列杂交设计，得到36个杂交组合；2002～2003年分别在河南省安阳和湖北省十堰进行田间鉴定，获取产量相关性状的试验数据，用混合线性（AD）模型和MINQUE（1）法（minimum norm quadratic unbiased estimation，最小范数二阶无偏估算法）对各性状遗传力、遗传方差分量及其占总表型变异的比率、群体的加性遗传效应和显性遗传效应进行剖析。联合分析结果显示：各性状的大多数遗传效应值都达到显著（P≤0.05）或极显著水平(P≤0.01)。各遗传方差分量的效应对小区产量贡献大小是显性显性与环境互作加性与环境互作加性；各性状狭义遗传力大小为穗行数行粒数穗长出籽率百粒重小区产量，加性效应最好的4个群体是Suwan1（31.69）、Stay green c4（25.44），WBM C4（14.15）和中综4号（10.29）；而显性效应比较好的4个组合为3×6（883.65）、1×3（572.20）、1×2（404.2376）和6×7（384.59）。在温带玉米育种中Suwan1和Stay green c4是最有利用价值的外来种质，它们都与BSSS C9构成杂种优势模式。在育种实践中，可以把Suwan1和Stay green c4杂交重组，并与BSSS C9构成一对温带和热带种质的杂种优势模式，可以进一步进行相互轮回选择。

English. The objectives of this study were: 1) to assess the breeding potential of maize populations including 2 of tropical origin and 7 of temperate origin; 2) to find a new heterotic pattern among the 9 populations. A 9-parent diallel was formed by Griffing IV and 36 crosses were obtained. The populations per se and crosses were evaluated in two different environments (Anyang of Henan Province and Shiyan of Hubei Province) during 2002-2003. Data for ear length (EL), number of rows per ear (RPE), number kernels per row (KPR), a hundred- kernels weight (HKW), ratio of kernels weight to the ear weight (RKW) and plot-kernels weight (PKW) were analyzed using a mixed (AD) model and MINQUE(1) methods; The heritability and genetic variance components for EL, RPE, KPR, HKW, RKW and PKW were estimated. The additive genetic effects for the populations and dominance genetic effects for the crosses were calculated. The parameters for almost all the traits concerned across the environments showed significant (P≤0.05) or highly significant (P≤0.01). Considering PKW that the ratio of genetic variance components to total variances are ranked as dominance dominance and#61620; environment additive and#61620; environment additive; The estimated of narrow sense heritability are sequenced as RPE KPR EL RKW HKW PKW. Concerning the additive and dominance effects for PKW that the top 4 populations are 1 (Suwan1), 6 (Stay green c4), 5 (WBM C4) and 9 (Zhongzong4), while the best 4 crosses are graded as 3×6 (BSSS C9×Stay green C4) 1×3(Suwan1×BSSS C9) 1×2(Suwan1 ×BS16) 6×7(Stay green C4×Liaolü population). This study provided helpful information for utilizing exotic germplasm in temperate breeding program, Suwan1 and Stay green c4 are very promising exotic germplasm, which with BSSS C9 must be performing a powerful heterotic pattern. Furthermore, it is useful in practical breeding to make a combination between Suwan1 and Stay green c4, which performs a new heterotic pattern with BSSS C9 between tropical and temperate maize germplasm. Reciprocal recurrent selection (RRS) scheme should be used in the future.