dahliae V991 and D8092 isolates ( Table 1). According to the RDIs, no CSIL line was immune to all three V. dahliae isolates ( Fig. 1). Only one CSIL showed high resistance to both the V. dahliae V991 and D8092 isolates. Respectively 16, 3, and 11 CSILs were resistant; 73, 78, and 79 were tolerant; OSI-744 nmr and 75, 84, and 74 were susceptible to V. dahliae V991, V07DF2 and D8092 isolates. These results indicated that fewer than 10% of the CSILs showed resistance to Verticillium wilt. A total of 42 QTL were identified and mapped on 18 chromosomes with LOD values
ranging from 3.00 to 9.29 (Table 2 and Table 3; Fig. 2). Of these QTL, 23 showed resistance-increasing effects and the remaining 19 showed susceptibility-increasing effects in response to the three V. dahliae isolates. Interestingly, most of QTL responded to different isolates. Based on RDIs obtained in the greenhouse experiment in 2009, 10 QTL showed resistance to V. dahliae V991 and were mapped on eight chromosomes, Chrs. A3, A7, A8, A9, A13, D4, D5, and D12, of which Chr. A3 and Chr. A7 contained two QTL each. The additive effect on increasing resistance to V. dahliae V991 ranged from − 11.04 to − 7.59 for a single Osimertinib in vitro QTL, and the phenotypic variation explained ranged from 1.7% to 3.7%. Eight susceptibility
QTL were detected on Chrs.A1, A3, A5, A12, D1, D2, and D3. Among these eight, two were located on Chr. D1. The additive effect of the decrease in G. hirsutum cv. TM-1 resistance to V. dahliae V991 ranged from 6.80 to 9.12, indicating Arachidonate 15-lipoxygenase that some resistance and/or tolerance QTL presenting G. hirsutum cv.TM-1 were substituted by susceptible chromosome segments from G. barbadense cv. Hai 7124, resulting in greater susceptibility of these CSILs than of G. hirsutum cv. TM-1. The percentage of PV ranged from 1.6 to 2.8%. Six QTL for resistance to V. dahliae V07DF2 were detected in the greenhouse experiments in 2010. Based on the RDIs of the CSILs, these six QTL were distributed on five chromosomes:
Chrs.A1, A4, A7, A9, and D11. Among six QTL, two QTL were located on Chr.A9. The additive effect of the increase in resistance to V. dahliae V07DF2 ranged from − 7.57 to − 6.43 for the resistance QTL and the percentage of PV ranged from 1.7 to 2.1%. In addition, seven susceptibility QTL were detected on Chrs.A1, A3, A5, A7, A9, D7, and D12, based on the RDIs of the CSIL population. The additive effect of the decrease in G. hirsutum cv. TM-1 resistance to the V. dahliae V07DF2 isolate ranged from 6.98 to 9.42 and the percentage of PV ranged from 1.8 to 3.3%. Seven QTL for resistance to V. dahliae D8092 were detected in the greenhouse experiments in 2011. Based on RDIs of the CSILs, these QTL were found to be distributed on six chromosomes, Chrs.A5, A7, A8, D1, D2 and D11. Among the seven, two were located on Chr.A5. The additive effect of the increase in resistance to V. dahliae D8092 ranged from − 11.96 to − 8.