Yield performance of chromosomally engineered durum wheat-Thinopyrum ponticum recombinant lines in a range of contrasting rain-fed environments across three countries

Abstract

Introgressions of Thinopyrum ponticum 7AgL chromosome segments spanning 23%, 28% and 40% of the distal end of durum wheat 7AL arm were previously shown to contain multiple beneficial gene(s)/QTL for yield-related traits. In the present study, durum wheat near isogenic recombinant lines (NIRLs) harbouring each of the three introgressions, were included for the first time in multilocation field trials, to evaluate general and environment-specific effects of the alien chromatin on 25 yield-related traits. The results from 11 different trials across contrasting environments of three countries and five years revealed that the presence of 7AgL chromatin had the strongest positive effect on spike (+11%) and grain number (+9%) m -2 , which represented the main contributors to the observed increases in grain yield and biomass (2-6%). In particular, grain yield was significantly increased (+18%) in 7AgL-carrier NIRLs in the water-limited South Australian environment. NIRLs carrying 23% and 28% 7AgL (named R5 and R112, respectively) displayed 2-30% higher grain yield with respect to the site's mean in most of the tested environments. Thus, also for other positive 7AgL genes they carry (Lr19, Sr25, Yp), they could be readily moved into site-directed breeding pipelines.Across all environments evaluated, the NIRL with a 40%-long 7AgL segment (named R23) resulted in increasing effects on grain number m -2 and spike -1 (averaging 47% and 14%, respectively) when compared with its control (no-7AgL). From comparison with the other NIRLs, this major gene/QTL can be located within the most proximal 28-40% 7AgL region, exclusive to the R23 recombinant. 2 The present study represents an important validation of the use of chromosomally engineered genetic stocks for targeted durum wheat improvement.

Wheat root systems as a breeding target for climate resilience

“…The importance of the lateral/axial root meristematic activity balance in wheat root deepening has also been highlighted in another study involving an alien introgression into bread wheat, in which a translocation from the wheat wild relative Agropyron elongatum on chromosome 7D caused impaired lateral root proliferation as a consequence of water deficit, resulting in the maintenance of meristematic activity of axial root apexes (Placido et al 2013). Chromosomally engineered durum wheat Thinopyrum ponticum recombinant lines tested in a range of contrasting rain-fed environments showed associated effects between seminal root angle and yield (Kuzmanović et al 2018). By exploring root gene transcription in lines contrasting for this introgression, as well as RNAi gene silencing in bread wheat, the gene LATERAL ROOT DENSITY (LRD) was identified as a repressor of root growth under drought conditions and was proposed to control the deeper rooting phenotype under drought conditions conferred by the Agropyron introgression (Placido et al 2020).…”

Combining QTL Analysis and Genomic Predictions for Four Durum Wheat Populations Under Drought Conditions

“…The Mediterranean basin is subject to frequent droughts and their occurrence is expected to raise in the near future, with a significant negative effect on crop development and production (Xiao et al, 2018). Breeding for durum genotypes that have an improved yield and tolerance to drought remains one of the most strategic methods to protect the harvest of this crop (Habash et al, 2009;Tadesse et al, 2016;Kuzmanoviae et al, 2018). The use of genomic models to analyze the main drought adaptation traits can be deployed to significantly accelerate the breeding effort.…”