Abstract:

: A recombinant inbred line population, derived from a cross between a high light-tolerant wheat Triticum aestivum cv. Xiaoyan 54 and a high yielding, but high light-sensitive variety, Jing 411, was used to explore the genetic relation between photosynthesis and grain yield-related traits. The net CO 2 assimilation rate, chlorophyll content, chlorophyll a fluorescence parameters, leaf area index, plant height, spike number, biomass, grain yield, and harvest index were evaluated in the field across two consecutive years. The results reveal that a total of 57 quantitative trait loci (QTL) are found to be associated with the investigated traits. They distributed on almost all 21 chromosomes, except for chromosomes 5D, 6D, 7A, and 7D. The phenotypic variance explained by a single QTL ranged from 9.3% to 39.9% depending on traits and QTL. Of these QTL, 12 QTL clusters were found to regulate at least 2 of the investigated traits, which distributed on 8 chromosomes, 1A, 1B, 2A, 2B, 2D, 3A, 3B, 4B and 5A. Seven QTL clusters were associated with both photosynthesis and grain yield-related traits, indicative of their genetic relation. Two QTL clusters on 2D and 4B were co-located with two reduced-height genes, Rht8 and Rht-B1b, respectively. These QTL clusters may be used as potential targets for wheat radiation use efficiency improvement in the future.

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