title: Classical genetic and quantitative trait loci analyses of heterosis in a maize hybrid between two elite inbred lines.
abstract: The exploitation of heterosis is one of the most outstanding advancements in plant breeding, although its genetic basis is not well understood yet. This research was conducted on the materials arising from the maize single cross B73 x H99 to study heterosis by procedures of classical genetic and quantitative trait loci (QTL) analyses. Materials were the basic generations, the derived 142 recombinant inbred lines (RILs), and the three testcross populations obtained by crossing the 142 RILs to each parent and their F(1). For seedling weight (SW), number of kernels per plant (NK), and grain yield (GY), heterosis was >100% and the average degree of dominance was >1. Epistasis was significant for SW and NK but not for GY. Several QTL were identified and in most cases they were in the additive-dominance range for traits with low heterosis and mostly in the dominance-overdominance range for plant height (PH), SW, NK, and GY. Only a few QTL with digenic epistasis were identified. The importance of dominance effects was confirmed by highly significant correlations between heterozygosity level and phenotypic performance, especially for GY. Some chromosome regions presented overlaps of overdominant QTL for SW, PH, NK, and GY, suggesting pleiotropic effects on overall plant vigor.
authors.affiliation: Department of Agroenvironmental Sciences and Technologies, University of Bologna, 40127 Bologna, Italy. elisabetta.frascaroli@unibo.it
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Frascaroli
authors.forename: Maria Angela
authors.initials: MA
authors.lastname: Canè
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Landi
authors.forename: Giorgio
authors.initials: G
authors.lastname: Pea
authors.forename: Luca
authors.initials: L
authors.lastname: Gianfranceschi
authors.forename: Marzio
authors.initials: M
authors.lastname: Villa
authors.forename: Michele
authors.initials: M
authors.lastname: Morgante
authors.forename: Mario Enrico
authors.initials: ME
authors.lastname: Pè
mesh_terms: D003433:Crosses, Genetic; D004843:Epistasis, Genetic; D006579:Heterozygote; D006823:Hybrid Vigor / Q000235:genetics*; D006824:Hybridization, Genetic; D007178:Inbreeding; D010641:Phenotype; D040641:Quantitative Trait Loci / Q000235:genetics*; D012044:Regression Analysis; D003313:Zea mays / Q000235:genetics*