Assessment of Variability for Drought Tolerance Indices in Some Wheat ( Triticum aestivum L.) Genotypes

Abstract

Introduction Bread wheat (Triticum aestivum L.) is annual crop, self-pollinator and contains Genome Hexoploid (AABBDD). Wheat, ranking second among cereals, supplies nutrients to more than one billion of population (Mergoum et al., 2009 and Braun et al., 2010). The demand of wheat is anticipated to increase by 40% in next ten years (FAO, 2015). Arid and semiarid areas adversely affected by drought environment that suffered from reducing more than 50% of yield crops (Jalilvandy & Mehdi, 2013). Plant breeders detected intensively for reliable and rapid method to combat drought problems. So, the researches on wheat to develop or introduce new superior genotypes or varieties that are very valuable (Subhani et al., 2012; Khan et al., 2013; Mahmood et al., 2013 and Aktas, 2016). These genotypes can tolerate serious drought stress without considerable reduction in grain yield. However, Talebi et al. (2009), Pireivatlou et al. (2010) and Koleva & Dimitrova E STIMATION of nine yield-based drought tolerance indices was studied in ten wheat genotypes and identification of best index and best drought tolerant genotype. Nine drought tolerance indices comprising stress tolerance index (STI), tolerance index (TOL), stress susceptibility index (SSI), geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HAM), yield index (YI), yield stability index (YSI) and drought resistance index (DRI) were each estimated based on yield under non-stress (Yp) and stress condition (Ys). The results of the genetic analysis for all drought tolerance indices studied demonstrated that GMP, MP and HAM had less variation between phenotypic coefficients of variability and genotypic coefficient of variability corresponded to high heritability. GMP, MP and HAM were nominated as the best useful indices that looking for drought tolerant genotypes. Also, they had positive correlation with Yp and Ys. The genotypes 1, 6 and 10 were considered drought tolerant while genotypes 3, 4, 5, 7 and 9 as drought susceptible. Genotype 8 was identified as highly drought susceptible. The studied genotypes showed considerable variation in performance and tolerated various drought conditions that could be exploited in further investigation.

Genetic study of some drought tolerance indicators in the first generation of durum wheat (Triticum durum Desf.)

“…While; the crosses 8×9, 5×9 and 5×10 were the least drought tolerant that recorded values of 0.228, 0.266 and 0.267, respectively. Similar; results were found in those of [17,18,[20][21][22] , for; Ys, Yp, TOL; SSI; GMP; MP and YSI; with different genotypes of wheat.…”

Genetic improvement for drought tolerance in rice using mutation induction

“…Whereas EN28, and EN7, with high SSI values of 2.37 and 1.87, respectively, can be considered susceptible to drought and only suitable for normal irrigation conditions. Similar results were recorded by Abdi et al (2013); Raman et al (2012); Eid and Sabry (2019) and Afiah et al (2019).…”

“…Further, they recommended that a high value of STI implies higher tolerance to abiotic stress. Similar findings are also documented by Farshadfar et (2015); Ali and El-Sadek (2016), and Eid and Sabry (2019).…”

“…The highest Tol values were related to mutants EN7 and EN28, which recorded values of 0.80 in WS1, while EN27 had the highest Tol value (1.47 in WS2). The high amount of Tol is a sign of susceptibility to stress (Parchin et al 2013;Eid and Sabry 2019).…”

Multivariate analysis of mutant wheat (Triticum aestivum L.) lines under drought stress

“…In addition, different drought tolerance parameters including stress tolerance index (STI) and geometric mean productivity (GMP) are being utilized for the selection of desired genotypes with adaptive potential against drought stress (Mohammadi and Abdulahi, 2017). However, under both well-watered and water-limited conditions, STI is found more useful for the selection of genotype with better productivity; the higher the value of STI, the more the genotype is considered to be drought tolerant (Eid and Sabry, 2019).…”