Dissecting gene × environmental effects on wheat yields via QTL and physiological analysis

Abstract

Crops frequently display genotype · environment interaction for yield and enduse quality in response to different environments, particularly when stresses such as water limitation and temperature are components of the interaction. Plant breeders usually exploit this variation via phenotypic selection to develop varieties with both general and specific adaptation. However the individual genes and physiological processes underlying the basis of general and specific adaptation have rarely been elucidated. We are combining large-scale QTL analysis of several doubled haploid populations of wheat, grown over different environments and seasons, with detailed physiological analysis, to dissect the genes and mechanisms responsible for yield and yield · environment variation in adapted European winter germplasm. Analysis of populations grown under irrigated and non-irrigated conditions on drought-prone soils has revealed individual genes showing stable and differential expression over environments, and the analysis has also identified physiological traits that contribute to differential yield performance. Genes on the homoeologous group 2 chromosomes were associated with flag leaf senescence (stay-green) variation and were the most significant in drought interactions. Variation for stem soluble carbohydrate reserves was associated with the 1RS arm of the 1BL/1RS translocated chromosome, and was positively correlated with yield under both irrigated and non-irrigated conditions, and thus general adaptability. Separate analyses of populations grown over three seasons in England, Scotland, France and Germany revealed QTL for yield performance showing both general and specific effects. A stable QTL on chromosome 6A, consistent in different populations, showed significant effects over seasons and environments, whilst other QTL were specific to season and/or environments.

A Genetic Framework for Grain Size and Shape Variation in Wheat

“…The DH populations and genetics maps used in this study were generated as was described previously (Snape et al, 2007;Griffiths et al, 2009) and summarized in Table 1. Specifically, they are as follows: Avalon 3 Cadenza (AxC), Beaver 3 Soissons (BxS), Shamrock 3 Shango (SxS), Spark 3 Rialto (SpxR), Malacca 3 Charger (MxC), and Savannah 3 Rialto (SaxR).…”

Genomics Approaches to Dissect the Genetic Basis of Drought Resistance in Durum Wheat

“…In bread wheat, QTLs for stem reserve, water-soluble carbohydrates (WSC) remobilization and leaf senescence have been reported across well-watered and waterstressed conditions (Snape et al 2007 ;Rebetzke et al 2008 ;Bennett et al 2012 ;Zhang et al 2015 ). Although these studies showed an important role for WSC in assuring stable yield and grain size, Rebetzke et al ( 2008 ) concluded that the small effects of many independent WSC QTLs may limit their direct use for MAS.…”

“…Although these studies showed an important role for WSC in assuring stable yield and grain size, Rebetzke et al ( 2008 ) concluded that the small effects of many independent WSC QTLs may limit their direct use for MAS. A combined QTL analysis for yield of several wheat populations evaluated across different environments and seasons enabled Snape et al ( 2007 ) to identify QTLs showing stable and differential expression across irrigated and non-irrigated conditions. Variation for stem water-soluble carbohydrate reserves was associated with the chr.…”

“…Variation for stem water-soluble carbohydrate reserves was associated with the chr. 1RS arm of the 1BL/1RS translocated (from rye to wheat) chromosome, and was positively associated with yield under both irrigated and rainfed conditions, thus contributing to general adaptability (Snape et al 2007 ). The benefi cial role of this translocation on wheat performance under drought-stressed conditions has already been reported (Ehdaie et al 2003 ).…”

“…not loci for fl owering time) across a broad range of soil moisture regimes becomes increasingly important to raise yield potential (Maccaferri et al 2008 ;Pinto et al 2010 ;Reynolds et al 2011 ;Turner et al 2014 ). Major QTLs for grain yield and its components across a broad range of soil moisture regimes have all been reported in bread wheat (Quarrie et al 2005 ;Kirigwi et al 2007 ;Snape et al 2007 ) with only one notable exception in durum wheat where Maccaferri et al ( 2008 ) searched for QTLs for grain yield in RILs evaluated in 16 environments with a broad range in grain yield values (from 0.56 to 5.88 t ha −1 ), mainly consequent to different soil moisture availability. Two major QTLs on chr.…”