El Hanafi Samira, Cherkaoui Souad, Kehel Zakaria, Sanchez-Garcia Miguel, Sarazin Jean-Benoit, Baenziger Stephen, Tadesse Wuletaw
International Center for Agricultural Research in the Dry Areas, Rue Hafiane Cherkaoui, Rabat-Institutes, Rabat B.P. 6299, Morocco.
Physiology Plant Biotechnology Unit, Bio-Bio Center, Faculty of Sciences, Mohammed V University of Rabat, 4 Avenue Ibn Battouta, Rabat B.P. 1014, Morocco.
Plants (Basel). 2022 Feb 14;11(4):508. doi: 10.3390/plants11040508.
Breeding hybrids with maximum heterosis requires efficient cross-pollination and an improved male sterility system. Renewed efforts have been made to dissect the phenotypic variation and genetic basis of hybrid floral traits, although the potential of tailoring the appropriate flower design on seed setting is less known. To this end, elite wheat genotypes were crossed using a chemical hybridizing agent at different doses. A total of 23 hybrids were developed from a partial diallel design; and planted in an alpha lattice design with their parents at two locations in Morocco, for two years, to evaluate for yield components, heterosis and combining abilities. The 13.5 L ha dose induced a maximum level of sterility (95%) and seed set showed large phenotypic variation and high heritability. In parallel, seed set showed tight correlation with pollen mass (0.97), visual anther extrusion (0.94) and pollen shedding (0.91) ( < 0.001), allowing direct selection of the associated traits. Using the combined data, mid-parent heterosis ranges were -7.64-14.55% for biomass (BM), -8.34-12.51% for thousand kernel weight (TKW) and -5.29-26.65% for grain yield (YLD); while best-parent heterosis showed ranges of -11.18-7.20%, -11.35-11.26% and -8.27-24.04% for BM, TKW and YLD, respectively. The magnitude of general combining ability (GCA) variance was greater than the specific combining ability (SCA) variance suggesting a greater additive gene action for BM, TKW and YLD. The favorable GCA estimates showed a simple method to predict additive effects contributing to high heterosis and thus could be an effective approach for the selection of promising parents in early generations.
培育具有最大杂种优势的杂交种需要高效的异花授粉和改良的雄性不育系统。尽管人们对根据种子结实情况定制合适的花型设计的潜力了解较少，但已重新努力剖析杂交花卉性状的表型变异和遗传基础。为此，使用不同剂量的化学杂交剂对优良小麦基因型进行杂交。通过部分双列杂交设计共培育出23个杂交种；并采用α格子设计将其与亲本一起种植在摩洛哥的两个地点，为期两年，以评估产量构成因素、杂种优势和配合力。13.5升/公顷的剂量诱导了最高水平的不育（95%），结实率表现出较大的表型变异和高遗传力。同时，结实率与花粉量（0.97）、花药可见伸出（0.94）和花粉散落（0.91）呈紧密相关（<0.001），从而能够直接选择相关性状。利用合并数据，生物量（BM）的中亲杂种优势范围为-7.64-14.55%，千粒重（TKW）为-8.34-12.51%，籽粒产量（YLD）为-5.29-26.65%；而最好亲本杂种优势的范围分别为BM的-11.18-7.20%、TKW的-11.35-11.26%和YLD的-8.27-24.04%。一般配合力（GCA）方差的大小大于特殊配合力（SCA）方差，表明BM、TKW和YLD存在更大的加性基因作用。有利的GCA估计值显示了一种预测对高杂种优势有贡献的加性效应的简单方法，因此可能是在早期世代选择有潜力亲本的有效途径。
