QTLs Mapping of some Growth Traits in Sunflower Seedlings under Salinity Stress Conditions

Salinity is one of the important abiotic stresses, which limit the crop production. In order to study the effect of several salinity levels (0, 2, 4, 6 and 8 (dS/m)), exerted by NaCl, on some growth traits of sunflower line and genetic analysis of several traits related to salinity tolerance, A factorial experiment carried out based on RCBD. In this study, some growth traits incuding shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight were evaluated in seedings. Results revealed statistical significant difference among RILs in several salinity levels. To genetic analysis of tolerance to salinity in sunflower seedlings, linkage map of SSR/SNP with 221 markers and average distance of 7.44 CM between markers used. Results of gene mapping manifested 18, 13, 4 and 10 QTLs in salinity levels of 0, 2, 4 and 6 (dS/m) for studied characteristics. In the salinity level of 8 (dS/m) due to lack of germination of seedlings, no QTL was found. The most significant QTLs with high explained phenotypic varition in salinity levels of zero, 2, 4, 6 dS/m were identified for root fresh weight (61.72%), root length (59.34 and 37%) and shoot dry weight (21.39%), respectively. Results showed some co-localized QTLs for several characteristics, which dispersed in some linkage groups. The co-localized QTLs could lead to increase the efficiency of marker-assisted selection in plant breeding programs.