Genetic analysis in recombinant inbred lines of early dent forage maize. II-QTL mapping for cell wall constituents and cell wall digestibility from per se value and top cross experiments
Year: 2002
Type: article
Abstract: Quantitative trait loci (QTL) affecting feeding value traits in forage maize were evidenced and mapped in a RIL (Recombinant Inbred Lines) progeny from the cross between the two early dent lines of contrasted cell wall digestibility F288 and F271. Traits studied were cell wall content and composition, whole plant digestibility and cell wall digestibility. Field evaluation was performed among a set of 131 RILs studied per se (3 years, 3 locations in year 1, 2 locations for the other two years, 3 replicates per location), and after top crossing with the early flint line F286 (2 years, 3 locations per year, 3 replicates per location). Heterosis was considered as the difference between hybrid (RIL x F286) value and average value of the parents (RIL and F286 per se). The genotypic effects were highly significant and always greater than genotype x environment interactions. Transgressive lines were observed for digestibility traits only towards higher values in RILs per se, and only towards lower values in top erass. A map was achieved with 108 SSR markers, chosen to cover the entire genome. However, large monomorphic areas were found because the two parental lines were both related to line Co125. Putative QTL were identified through composite interval mapping. and are given for LOD values higher than 2.0. Additive x additive epistatic effects were investigated. QTL observed in RILs per se were logically more numerous than QTL found in top cross, but some QTL found in top cross were not found in RILs per se. QTL involved in heterosis for cell wall content or digestibility were also observed. Five major clusters of QTL were found for digestibility and lignification traits. In descending order for their LOD values or percentage of explained phenotypic variation, the clustered QTLs were located. in bins 6.06, 3.05, 2.08, 6.01 and 9.02. QTL for NDF, Hcell/NDF and Cell/NDF were also found in bins 2.08 and 6.06. QTL greatly involved in heterotic effects, both for digestibility traits and lignin content, were observed in bins 5.05 and 8.05. Significant simultaneous improvement of top cross yield, earliness, protein content and digestibility was proven to be possible by MAS based on the high yielding RIL n° 143 and five other RILs, sources of favorable alleles for the respective traits under breeding.
Source: HAL
Language: English
Subfield: Genetics
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W2521577477