Abstract:
The capability of a genotype
to achieve acceptable yield over a broad
range of sub-optimum and suitable conditions
is extremely imperative. Late planting and
end-season drought stress are two main
factors limiting wheat yield in northwest of
Iran. In a 2-year field experiment at
Miandoab, Iran, the ability of several
selection indices to identify drought
resistant genotypes under different sowing
dates and moisture conditions were
evaluated. Six genotypes of differing
response to water scarcity were planted at
20-d intervals on three dates from 11
October to 20 November. Drought
resistance indices were utilized on the basis
of grain yield under end-season drought
(Ys) and normal (YN) conditions. Evaluation
of MP, HARM, GM, STI, TOL, SSI, RDI,
YSI and Yr indicated that late sowing (20
Nov) significantly decreased drought
tolerance in all investigated genotypes.
However, yield comparisons under normal
and terminal drought stress conditions
revealed that promising lines (C-81-4, C-81-
10, C-81-14 and C-82-12) had better
performance than local checks (Zarrin and
Alvand). Furthermore under both moisture
conditions C-81-10 genotype had the
greatest grain yield. Based on drought
indices like as MP, GMP, STI and HARM
C-81-10 genotype introduced as the most
tolerant genotype to end-season drought
stress. Grain yield showed a positive and
significant correlation with HARM, GMP,
MP, STI and YI indices were more efficient
for recognizing high performance genotypes
under different sowing dates and diverse
moisture stress.
