Physiological and Genetic Drivers Underpinning Canopy Development are Associated with Durum Wheat Yield in Rainfed Environments

Abstract

Durum wheat (Triticum turgidum L. ssp. Durum) is largely grown in rainfed production systems around the world. New cultivars with improved adaptation to water-limited environments are required to sustain productivity in the face of climate change. Physiological traits related to canopy development underpin the production of biomass and yield, as they interact with solar radiation and affect the timing of water use throughout the growing season. Despite their importance, there is limited research on the relationship between canopy development and yield in durum wheat, in particular studies exploring temporal canopy dynamics under field conditions. This study reports the genetic dissection of canopy development in a durum wheat nested-association mapping population evaluated for longitudinal normalized difference vegetation index (NDVI) measurements. Association mapping was performed to identify quantitative trait loci (QTL) for time-point NDVI and spline-smoothed NDVI trajectory traits. Yield effects associated with QTL for canopy development were explored using data from four rainfed field trials. Four QTL were associated with yield in specific environments, and notably, were not associated with a yield penalty in any environment. Alleles associated with slow canopy closure increased yield. This was likely due to a combined effect of optimised timing of water-use and pleiotropic effects on yield component traits, including spike number and spike length. Overall, this study suggests that slower canopy closure is beneficial for durum wheat production in rainfed environments. Selection for traits or loci associated with canopy development may indirectly improve yield and support selection for more resilient and productive cultivars in water limited environments.

A multi-reference parent nested-association mapping population to dissect the genetics of quantitative traits in durum wheat

“…In addition to the previously reported QTLs for PH and DTF, six novel QTLs controlling DTF and six for PH were detected using the dNAM population developed in our study. Notably, dNAM has also been successfully used to map key drought-adaptive traits such as canopy dynamics and root system architecture (Alahmad et al 2019;Kang et al 2021). Perhaps the QTLs reported for above-and belowground traits using the dNAM populations developed in this study could be evaluated in multiple environments and used as markers for assisted breeding and introgression into elite germplasm.…”

“…While mapping traits by analysing the whole dNAM population would be desirable, it would be more cost effective to analyse the 10 parental lines for a trait of interest. Based on the results, sub-populations derived from donors carrying the desirable trait could then be evaluated, enabling a more targeted mapping approach (Alahmad et al 2019; Alahmad et al 2020; Kang et al 2021). This approach would be particularly suitable for time-consuming assays or eld experiments that are expensive and require large numbers of genotypes.…”

Effect of End-of-Season Drought Stress on Grain Yield and Some Morphological Traits in Wheat Genotypes Hexaploid Tolerant and Sensitive to Stress

“…According to statistics published by the General Statistics and Information Department of the Ministry of Jahad Agriculture, the average yield of irrigated wheat in Iran over the past two decades there is a growing but non-uniform trend that according to research, the most important factor is changes in rainfall. It is a season especially in the stages of pollination and flowering of the plant -critical stages of plant growth [2]. In the studies of many researchers, the effi-ciency of selecting drought-resistant cultivars based on yield under favorable conditions due to their large size, lack of complete separation and unpredictability the interactions of genotype and environment have been questioned.…”