QTLs for the vascular bundle system of the uppermost internode using a doubled haploid population of two elite Chinese wheat cultivars

With 3 figures and 2 tables Abstract A doubled haploid population of 168 lines of wheat ( Triticum aestivum L.) was used for quantitative trait loci (QTL) analysis of vascular bundle system in uppermost internode including the total vascular bundles (TVB), the large vascular bundles (LVB), the small vascular bundles (SVB), and the ratio of large vs. small vascular bundles (L/S) in four environments. Fourteen additive QTLs and one pair of epistatic QTLs were identified. For TVB, five QTLs on chromosomes 1A, 2D (two regions), 5D and 7D were detected and explained 48.85% of phenotypic variation; one QTL on chromosome 5D controlling LVB explained 22.95% of the variation; six QTLs for SVB, on chromosomes 1A, 2D, 5D (two regions), 6A, and 7D accounted for 81.58% of the total variation. Two QTLs explaining 27.62% for L/S were identified on chromosomes 5D, and 7D. In addition, one pair of significant epistatic QTLs was identified for TVB, and explained 10.81% of the phenotypic variation on chromosomes 2A and 6D. These results demonstrated that additive QTLs with pleiotropic and multigenic effects, additive and epistatic effects were subjected to environmental susceptibility.