Mapping single nucleotide polymorphisms (SNPs) in wheat (Triticum aestivum L.) can help to develop high throughput molecular markers for important traits. The 90K Infinium iSelect SNP array was used to screen three recombinant inbred line (RIL) populations derived from three crosses, CO 960293‐2/'TAM 111’ (CT), ‘TAM 112’/TAM 111 (TT), and ‘Halberd’/'Len’ (HL). The objective of this study was to compare and validate the chromosomal locations of mapped SNPs in wheat. A set of 152, 124, and 180 RILs were used in CT, TT, and HL. Among the 91,829 SNPs, 54,258 SNPs were called at least in one mapping population. A set of 5950, 4861, and 8376 SNPs were mapped onto chromosomes of CT, TT, and HL, respectively, with a total of 15,604 unique SNPs. Only 374 SNPs (2.4%) were commonly mapped across three populations, and 3025 SNPs (19.4%) were mapped across all combinations of two of the three populations. The number of uniquely mapped SNPs specific to each population was 3291 (21.1%) in CT, 2418 (15.5%) in TT, and 6224 (40.0%) in HL. With known chromosomal locations of the mapped 40K out of 90K array SNPs, linkage groups in all three mapping populations were assigned onto chromosomes. More than 76% of the mapped SNPs have consistent chromosomal locations with the previously mapped 40K SNPs. A set of 2190 (14.0%) unique newly mapped SNPs and 1316 (8.4%) SNPs mapped onto multiple chromosomes were presented. These chromosome maps are essential for the discoveries of genes and quantitative trait loci (QTL) of important traits in wheat.

Water deficit is one of the primary causes of decreasing wheat (Triticum aestivum L.) yields. Previous studies have identified associations in genomic regions with cooler canopies, the heat‐susceptible index, and grain yield in spring wheat. This project aimed to define the role of leaf epicuticular wax (EW) as a drought‐adaptive trait for improving the production and stability of yield attributes. A recombinant inbred line (RIL) population created from two spring wheat cultivars (‘Halberd’ and ‘Len’) was used. The parent lines were selected because of their different responses to drought, with Halberd exhibiting better water deficit tolerance. In five environments, an α lattice design with two replications and two distinct moisture treatments (water deficit and irrigated) were implemented. The RILs exhibited significant segregation for leaf EW, canopy temperature (CT) and drought susceptibility index (DSI). The inheritance of leaf EW was low (0.15) because of significant environment interactions. The RILs grown under water deficit produced significantly higher EW content (19–30%) compared with those under irrigation. The leaf EW significantly correlated with plot yield (r = 0.32) and leaf CT (r = ‐0.32) and the DSI for mean single head weight (r = ‐0.23) at Uvalde 2012 under water deficit. In addition, EW and CT correlated with stability parameters (DSI, regression of coefficient, and regression mean square) of different yield components within and across water deficit environments. This study explains the inter‐relationship between leaf EW and CT in improving wheat adaptability to moisture and heat stress.

Changes in leaf epicuticular wax load and its effect on leaf temperature and physiological traits in wheat cultivars (Triticum aestivum L.) exposed to high temperatures during anthesis T AbstractThe physiological functions of epicuticular wax (EW) include reflectance of irradiation and the reduction of water loss. When a plant experiences stressful conditions, most notably, high irradiance and temperature, damage to the photosynthetic apparatus can occur and is signalled by a decrease in the F v /F max ratio. In this study, we

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