Drought-Tolerance QTLs Associated with Grain Yield and Related Traits in Spring Bread Wheat

Abstract

The present research aims to identify the efficient combination of drought-tolerance selection
criteria and associated quantitative trait loci. A panel of 197 bread wheat genotypes was
evaluated for yield- and drought-tolerance-related traits in two environments (favorable and semiarid)
for 2 years (2015–2016). Grain number, biomass, number of fertile spikes per plant and ground
cover exhibited a significant correlation with grain yield and constitute potential secondary selection
criteria for yield under drought conditions. About 73 significant marker–trait associations were
detected along various chromosomal positions. The markers “wsnp_Ex_Rep_c67786_66472676” and
“ExcalibuR_c24593_1217” exhibited important genetic gains associated with yield increase under
drought (11 and 7%, respectively). The markers “KukRi_c94792_127” and “wsnp_Ex_c298_580660”
showed a significant correlation with grain yield, biomass and grain number and were associated
with a significant increase in yield performance at the semiarid site (+6 and +7%, respectively).
The ground cover was found associated with grain yield and biomass through the markers
“wsnp_Ex_Rep_c67786_66472676” (+11%) and “KukRi_c49927_151” (+10%). One marker “Tdu-
RuM_contig25432_1377” on chromosome 5B at 20 cM was consistently correlated with the number
of fertile spikes across both environments. Further research should be considered to validate the
efficiency of these markers to