Identification of Molecular Genetic Markers Associated with Salt Tolerance in Pearl Millet (Pennisetum Glaucum L.)
Keywords:Chemical analysis, ISSR, quantitative trait loci (QTLs), pearl millet, salinity stress
Soil salinity is the principal abiotic stress that hinders plant growth and agricultural productivity. The salinity affects plant growth by the osmotic stress and ionic toxicity as well as ion imbalance. Therefore, it is necessary to screen germplasm with salt tolerance. In a randomized complete block design with four replications,five genotypes of pearl millet (Pennisetum glaucum L.) were evaluated under salinity soil durnig 2019 and 2020 seasons. The experiment was conducted at Sahl El-Hussinia, Agricultural Research Station, El-Sharkia Governorate, Egypt. This work aimed to evaluate five pearl millet genotypes under salinity stress based on yield, yield components, chemical and molecular analysis using the Inter-Simple Sequence Repeat (ISSR) marker. The results showed that the 2019 season had the highest values for all traits studied in this study compared to the 2020 season, and these values revealed high statistically significant differences between the genotypes of millet that were examined in the resistance to salt stress for different traits in both seasons. PE00463 genotype surpassed all other genotypes for plant height, number of tillers/m2 and total fresh dry forage yields, as well as crude fiber and crude protein Followed by PE00200 genotype, whereas the genotype PE000194 was recorded with
the lowest values, indicating the presence of genetic variability within all genotypes to saline stress tolerance. A total of 56 ISSR bands were recorded, 27 and 29 of monomorphic and polymorphic bands, respectively. Three out of eight primers showed some molecular markers for salinity tolerance. Similarity relationships among pearl millet genotypes based on ISSR were ranged between 0.884 and
0.635. The dendrogram resulting separated the five pearl millet genotypes into two main groups and sub-main groups. The principal component analysis (PCA) has grouped the genotypes into three different groups that estimated 68.7% of the total variance in the values of the differences for the studied traits. The first and second principal components (PC1 and PC2) explained 40.4% and 28.3%,
respectively. The heat map assignment analyses were used; the genotypes were distributed into two main clusters. Therefore, PE00463 and PE00200 genotypes can tend to new promising and more tolerant genotypes with salt stress.
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