Tolerance Indices and Cluster Analysis to Evaluate Some Bread Wheat Genotypes under Water Deficit Conditions

The present study was carried-out at the Experimental Farm of Sakha Agricultural Research Station, during
2017/2018 and 2018/2019 seasons to evaluate eighteen bread wheat genotypes including fourteen promising lines and four
cultivars namely; Sakha 93, Sakha 95, Giza 171 and Shandaweel 1 under normal irrigation and deficit conditions.
Additionally, six selection indices were used to identify the best genotypes that might be grown under water deficit
condition using different drought indices namely; Mean Productivity (MP), Harmonic Mean (HM), Geometric Mean
Productivity (GMP), Stress Tolerance Index (STI), Yield Index (YI), and Modified Stress Tolerance Index (MSTI). The
results indicated that, the effect of the irrigation treatments, genotypes and their interactions were significantly different in
most studied characteristics. The means of all genotypes significantly decreased in all characters except for, proline
content that was increased in the two growing seasons under water deficit conditions compared with to normal condition.
Genotype 5 recorded the highest number of spikes /m², while the heaviest 1000-kernel weight was produced from Giza
171 under normal and water deficit condations. Sakha 95 gave the highest values for grain yield under both conditions.
Based on drought indices HM, GMP, STI, YSI and MSTI, genotype 3 followed by Sakha 95, Shandweel 1, genotype 5
and Giza 171 were identified as suitable genotypes for water deficit conditions. The cluster analysis classified the tested
genotypes into five main different groups, each group contained similar genotypes similar based on grain yield and stress
tolerance indices. The fifes cluster consisted of one genotype (Sakha 95) that recorded high grain yield and stress
tolerance degree followed by the third cluster which consisted of genotypes 3, 5, Giza 171 and Shandaweel 1 which had a
moderate grain yield and tolerance to water deficit genotypes. So these genotypes might be used as parents in breeding
programes to produce new genotypes with desirable characters related to drought tolerance.