Investigation of cotton f3 - f4 generations in terms of tolerance to verticillium wilt disease, yield and fiber quality characteristics and validation of some molecular markers associated with the mentioned disease

This study was conducted in 2016 and 2017 to examine the tolerance to Verticillium wilt disease, yield and fiber quality characteristics of cotton F3 and F4 generations. This work was also conducted to verify 18 SSR markers present in QTL regions closely associated with the above mentioned disease. The study was carried out in accordance with the pedigree method. Trials were established with 4 replications according to the progeny rows in 2016 (F3) and the combined family blocks design pattern in 2017 (F4). Genotypes used as controls [parents (VD-4 and Stoneville 468) and standard varieties (Carisma, Flash and Lydia)] planted as repeats and in four rows while seeds from single plants were planted as separate rows. Differences among the controls were statistically significant at 1% level for disease index determined by leaf and vascular tissue symptoms, at 5% for fiber elongation. On the other hand, it was determined that differences among the genotypes used as control were statistically significant at 1% level in terms of ginning turnout for 2016 and spinning consistency index for 2017. However, it was determined that the average values of the populations for the F3 and F4 generations differ statistically in terms of all the characteristics examined. In addition, it has been determined that the populations have a wide variation in terms of all characteristics studied. Furthermore, molecular work done in this study indicate that GH215 marker is associated with Verticillium wilt disease in cotton.