Abstract
Heterosis helps increase the biomass of many crops; however, while models for its mechanisms have been proposed, it is not yet fully understood. Here, we use a QTL analysis of the progeny of a high-biomass sorghum F1 hybrid to examine heterosis. Five QTLs were identified for culm length and were explained using the dominance model. Five resultant homozygous dominant alleles were used to develop pyramided lines, which produced biomasses like the original F1 line. Cloning of one of the uncharacterised genes (Dw7a) revealed that it encoded a MYB transcription factor, that was not yet proactively used in modern breeding, suggesting that combining classic dw1or dw3, and new (dw7a) genes is an important breeding strategy. In conclusion, heterosis is explained in this situation by the dominance model and a combination of genes that balance the shortness and early flowering of the parents, to produce F1 seed yields.
Highlights
Heterosis helps increase the biomass of many crops; while models for its mechanisms have been proposed, it is not yet fully understood
The F 2 plants were crossed between the MS79A (CMS) and 74LH3213 lines in 2013 and 2014, and between the MS79B and 74LH3213 lines in 2015 and 2018, to eliminate the linkage of the restorers of fertility (Rf) loci
We have conducted a genetic analysis of the sorghum variety ‘Tentaka’, a Japanese F1 hybrid, which shows typical and intense heterosis
Summary
Heterosis helps increase the biomass of many crops; while models for its mechanisms have been proposed, it is not yet fully understood. Heterosis is explained in this situation by the dominance model and a combination of genes that balance the shortness and early flowering of the parents, to produce F1 seed yields. The phenomenon of heterozygous hybrid plants having superior performance to their parental inbred lines, is known as heterosis It has been utilized in crop breeding around the world, as it can result in superior seed yields and biomass, and increased resistance to biological and non-biological s tresses[1]. The dominance model states that heterosis is caused by the complementation of deleterious recessive alleles[2,3] This model predicts that an inbred line of equal performance to the F 1 hybrid could be achieved by eliminating all deleterious alleles and accumulating favourable a lleles[15]. Of the five QTLs identified for CL, an uncharacterised gene
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