Morphological and Genetic Diversity within Salt Tolerance Detection in Eighteen Wheat Genotypes

Abstract

Salinity is a major obstacle to wheat production worldwide. Salt-affected soils could be used by improving salt-tolerant genotypes depending upon the genetic variation and salt stress response of adapted and donor wheat germplasm. We used a comprehensive set of morpho-physiological and biochemical parameters and simple sequence repeat (SSR) marker technique with multivariate analysis to accurately demonstrate the phenotypic and genetic variation of 18 wheat genotypes under salinity stress. All genotypes were evaluated without NaCl as a control and with 150 mM NaCl, until the onset of symptoms of death in the sensitive plant (after 43 days of salinity treatment). The results showed that the relative change of the genetic variation was high for all parameters, heritability (>60%), and genetic gain (>20%). Stepwise regression analysis, noting the importance of the root dry matter, relative turgidity, and their respective contributions to the shoot dry matter, indicated their relevance in improving and evaluating the salt-tolerant genotypes of breeding programs. The relative change of the genotypes in terms of the relative turgidity and shoot dry matter during salt stress was verified using clustering methods. For cluster analysis, the genotypes were classified into three groups: tolerant, intermediate, and sensitive, representing five, six, and seven genotypes, respectively. The morphological and genetic distances were significantly correlated based on the Mantel test. Of the 23 SSR markers that showed polymorphism, 17 were associated with almost all examined parameters. Therefore, based on the observed molecular marker-phenotypic trait association, the markers were highly useful in detecting tolerant and sensitive genotypes. Thus, it considers a helpful tool for salt tolerance through marker-assisted selection.

Multidimensional Evaluation for Detecting Salt Tolerance of Bread Wheat Genotypes Under Actual Saline Field Growing Conditions

“…Therefore, these parameters can be used as individual or complementary screening criteria for evaluating the salt tolerance of wheat genotypes under field conditions. These findings are consistent with previous studies that indicate several important physio-biochemical parameters that are useful and effective screening criteria for evaluating salt tolerance of wheat genotypes and as good indicators for grain yield and its related components under salinity stress [ 14 , 36 , 49 ].…”

“…Unfortunately, the success in enhancing genotypic salt tolerance is very limited. One factor for this limitation is that the majority of salinity studies that evaluate genotypic salt tolerance were carried out under tightly controlled conditions, and these studies are focused on evaluating genotypic salt tolerance at early growth stages [ 14 , 36 , 45 , 46 , 47 , 49 ]. More importantly, the relative studies seldom use physio-biochemical attributes as evaluation criteria for genotypic salt tolerance, although these attributes are functions of various physiologic processes and reflect the response of these processes to salt stress at the canopy, organ, tissue, and cellular levels [ 39 , 74 , 75 ].…”

“…Indeed, wheat genotypes have different potentialities in adapting with salt stress and producing satisfactory grain yield under natural salinity stress conditions. Several researchers demonstrated considerable genetic variations in salinity tolerance in bread wheat using different experimental setups carried out under either controlled or simulated field conditions [ 14 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. However, evaluating the salt tolerance of field crops should be confirmed until the yielding stage and, most importantly, should be performed under real field conditions, especially when the evaluation of salt tolerance happens in the advanced generation of breeding programs [ 14 , 50 , 51 ].…”

Selection criteria for high-yielding and early-flowering bread wheat hybrids under heat stress

“…Simple sequence repeat (SSR) markers, also known as microsatellites, are among the most important molecular markers; they are multi-allele, co-dominant, highly informative, relatively highly abundant, widely distributed across the genome, and reproducible [ 11 , 12 ]. SSRs are very advantageous for various applications in genetic research and breeding, population structure analysis, gene mapping, assisted selection for crop improvement, and genetic diversity estimation of wheat cultivars and lines [ 13 – 18 ].…”

Molecular Assessment of Genetic Diversity among Egyptian Landraces of Wheat (Triticum aestivum L.) Using Microsatellite Markers

“…Grouping of wheat genotypes via SSR markers into different clusters have relevance to the future breeding programs [22,48,49]. In the present study, The SSR analysis classified the landraces and cultivars into four groups.…”