Inter-Simple Sequence Repeat (ISSR) Markers to Study Genetic Diversity Among Cotton Cultivars in Associated with Salt Tolerance

Abstract

Developing salt-tolerant crops is very important as a significant proportion of cultivated land is salt-affected. Screening and selection of salt tolerant genotypes of cotton using DNA molecular markers not only introduce tolerant cultivars useful for hybridization and breeding programs but also detect DNA regions involved in mechanism of salinity tolerance. To study this, 28 cotton cultivars, including 8 Iranian cotton varieties were grown in pots under greenhouse condition and three salt treatments were imposed with salt solutions (0, 70 and 140 mM NaCl). Eight agronomic traits including root length, root fresh weight, root dry weight, chlorophyll and fluorescence index, K+ and Na+ contents in shoot (above ground biomass), and K+/Na+ ratio were measured. Cluster analysis of cultivars based on measured agronomic traits, showed ‘Cindose’ and ‘Ciacra’ as the most tolerant cultivars, and ‘B-557’ and ‘43347’ as the most sensitive cultivars of salt damage. A total of 65 polymorphic DNA fragments were generated at 14 inter-simple sequence repeat (ISSR) loci. Plants of 28 cultivars of cotton grouped into three clusters based on ISSR markers. Regression analysis of markers in relation with traits data showed that 23, 33 and 30 markers associated with the measured traits in three salt treatments respectively. These markers might help breeders in any marker assisted selection program in order to improving cotton cultivars against salt stress.