摘要：The resistance to tomato yellow leaf curl disease was evaluated and analyzed in tomato plants of CLN2498E (source of resistance), Castle Rock, and their progenies F1, F2 and BC 1F1 populations using a sequence tagged site marker, linked to Ty-2 gene (T0302). Three viral strains (TYLCV-Has, TY- LCV-IL and TYLCV-Pep) were used for segregation of resistance and disease evaluation for both parents and their progenies. Results showed that CLN2498E carried Ty-2 gene marker but Castle Rock did not have this resistance gene. The F2 and BC1F1 plants were segregated for Ty-2 with ratio closed to 3:1 (X2=0.86) and 1:1 (X2=0.60), respectively. These ratios indicated that Ty-2 gene was simply inherited into the F2 and BC1F1. The phenotypic screening results showed that the resistance to infection was dependent on the type of viral strain. The line CLN2498E was resistant to TYLCV-Has and TYLCV-IL while Castle Rock was susceptible. The plants those have Ty-2 gene homozygous (Ty- 2/Ty-2) or heterozygous (Ty-2/ty2) were resistant to TYLCV-Has and TYLCV-IL while the plants did not carry Ty-2 gene were susceptible for both strains. In contrast, all the plants were susceptible to TYLCV-Pep even if they were carrying the resistance gene ( Ty-2) .
