Lu H-J, Bernardo R, Ohm H W
Department of Agronomy, University of Missouri-Columbia, 205 Curtis Hall, Columbia, MO 65211, USA.
Theor Appl Genet. 2003 Feb;106(3):423-7. doi: 10.1007/s00122-002-1041-y. Epub 2002 Aug 16.
Popping expansion volume is the most important quality trait in popcorn ( Zea mays L.), but its genetics is not well understood. The objectives of this study were to map quantitative trait loci (QTLs) responsible for popping expansion volume in a popcorn x dent corn cross, and to compare the predicted efficiencies of phenotypic selection, marker-based selection, and marker-assisted selection for popping expansion volume. Of 259 simple sequence repeat (SSR) primer pairs screened, 83 pairs were polymorphic between the H123 (dent corn) and AG19 (popcorn) parental inbreds. Popping test data were obtained for 160 S(1) families developed from the [AG19(H123 x AG19)] BC(1) population. The heritability ( h(2)) for popping expansion volume on an S(1) family mean basis was 0.73. The presence of the gametophyte factor Ga1(s) in popcorn complicates the analysis of popcorn x dent corn crosses. But, from a practical perspective, the linkage between a favorable QTL allele and Ga1(s) in popcorn will lead to selection for the favorable QTL allele. Four QTLs, on chromosomes 1S, 3S, 5S and 5L, jointly explained 45% of the phenotypic variation. Marker-based selection for popping expansion volume would require less time and work than phenotypic selection. But due to the high h(2) of popping expansion volume, marker-based selection was predicted to be only 92% as efficient as phenotypic selection. Marker-assisted selection, which comprises index selection on phenotypic and marker scores, was predicted to be 106% as efficient as phenotypic selection. Overall, our results suggest that phenotypic selection will remain the preferred method for selection in popcorn x dent corn crosses.
爆裂膨胀体积是爆米花（Zea mays L.）最重要的品质性状，但其遗传机制尚未完全明晰。本研究的目的是在一个爆米花×马齿型玉米杂交组合中定位控制爆裂膨胀体积的数量性状位点（QTL），并比较针对爆裂膨胀体积的表型选择、基于标记的选择和标记辅助选择的预测效率。在筛选的259对简单序列重复（SSR）引物对中，有83对在亲本自交系H123（马齿型玉米）和AG19（爆米花）之间表现出多态性。从[AG19(H123×AG19)]BC(1)群体中获得了160个S(1)家系的爆裂测试数据。基于S(1)家系均值的爆裂膨胀体积遗传力（h(2)）为0.73。爆米花中配子体因子Ga1(s)的存在使爆米花×马齿型玉米杂交组合的分析变得复杂。但是，从实际角度来看，爆米花中有利QTL等位基因与Ga1(s)之间的连锁将导致对有利QTL等位基因的选择。位于第1S、3S、5S和5L染色体上的4个QTL共同解释了45%的表型变异。针对爆裂膨胀体积的基于标记的选择比表型选择所需的时间和工作量更少。但是由于爆裂膨胀体积的h(2)较高，预计基于标记的选择效率仅为表型选择的92%。标记辅助选择包括对表型和标记评分的指数选择，预计效率为表型选择方法的106%。总体而言，我们的结果表明，在爆米花×马齿型玉米杂交组合中，表型选择仍将是首选的选择方法。
