Parsons Leandra, Ren Ying, Yobi Abou, Hurst Preston, Angelovici Ruthie, Rodriguez Oscar, Holding David R
Department of Agronomy and Horticulture, University of Nebraska - Lincoln, Lincoln, NE, United States.
Center for Plant Science Innovation - Beadle Center for Biotechnology, University of Nebraska, Lincoln, NE, United States.
Front Plant Sci. 2020 Jun 23;11:698. doi: 10.3389/fpls.2020.00698. eCollection 2020.
Popcorn varieties are agronomically sub-optimal and genetically limited compared to other maize subspecies. To increase genetic diversity and improve popcorn agronomics, dent germplasm has been introduced to popcorn with limited success and generally, major loss of popping. Between 2013 and 2018, 12 Quality Protein Popcorn (QPP) inbreds containing Quality Protein Maize (QPM) and popcorn germplasm were produced that maintained popping while carrying the allele conferring elevated kernel lysine. This is an opportune trait in the growing market for healthier snacks and a model for mining QPM traits into popcorn. We crossed QPP inbreds to explore the effects of heterosis on popcorn protein, popping quality, and plant agronomics and selected hybrids for further production. To rank and intermediately prescreen hybrids, we utilized a novel hybrid-ranking model adapted from a rank summation index while examining the inbred general combining ability and hybrid specific combining ability estimates for all traits. We observed a biological manifestation of heterosis by categorizing hybrids by pedigree that resulted in a stepwise progression of trait improvement. These results corroborated our hybrid selection and offered insight in basic heterosis research. Estimates for popcorn quality and agronomic trait covariances also suggest the synergistic introgression of highly vitreous dent maize (QPM) into popcorn, providing a likely explanation for the successfully maintained vitreous endosperm, protein quality and popping traits in line with a remodeled proteome. QPP hybrids maintained improved amino acid profiles although different popping methods variably affected popcorn's protein bound and free amino acid levels. This preliminary screening of QPP hybrids is enabling further quantitative selection for large-scale, complex trait comparison to currently marketed elite popcorn varieties.
与其他玉米亚种相比，爆米花品种在农艺学上并不理想，且遗传特性有限。为了增加遗传多样性并改善爆米花的农艺性状，已将马齿型种质引入爆米花，但成效有限，且通常会导致爆花率大幅下降。在2013年至2018年期间，培育出了12个含有优质蛋白玉米（QPM）和爆米花种质的优质蛋白爆米花（QPP）自交系，这些自交系在携带赋予籽粒赖氨酸含量升高的等位基因的同时保持了爆花特性。在健康零食市场不断增长的背景下，这是一个有利的性状，也是将QPM性状挖掘到爆米花中的一个模型。我们将QPP自交系进行杂交，以探索杂种优势对爆米花蛋白质、爆花品质和植株农艺性状的影响，并选择杂交种用于进一步生产。为了对杂交种进行排名和初步预筛选，我们采用了一种从秩和指数改编而来的新型杂交种排名模型，同时考察了所有性状的自交系一般配合力和杂交种特殊配合力估计值。我们通过按系谱对杂交种进行分类观察到了杂种优势的生物学表现，这导致了性状的逐步改善。这些结果证实了我们的杂交种选择，并为基础杂种优势研究提供了见解。对爆米花品质和农艺性状协方差的估计还表明，高玻璃质马齿型玉米（QPM）成功渗入爆米花，这为成功维持玻璃质胚乳、蛋白质品质和爆花性状提供了一个可能的解释，这与重塑的蛋白质组一致。尽管不同的爆花方法对爆米花结合蛋白和游离氨基酸水平有不同影响，但QPP杂交种保持了改善的氨基酸谱。对QPP杂交种的这种初步筛选能够进一步进行定量选择，以便与目前市场上的优质爆米花品种进行大规模、复杂性状比较。
