Ornubol Chomdej, Uraiwan Pongpayaklers, and Julapark Chunwongse

pp. 23 - 36

Abstract

The BC₂
F₁
 population from a cross between wild tomato, Solanum habrochaites ‘L06112’ and recurrent susceptible
variety, Seedathip 3 was investigated for a resistance to Tomato yellow leaf curl Thailand virus (TYLCTHV-[2]). Five stem
cuttings from each of the 196 lines were inoculated with TYLCTHV-[2] using viruliferous whiteflies as the inoculation vector.
Disease response was recorded weekly intervals and scored for three weeks according to the severity of the symptoms. The
presence of TYLCTHV-[2] was confirmed by enzyme-linked immunosorbent assay (ELISA) at three weeks after inoculation.
ELISA readings showed a normal distribution for the BC₂
F₁
 population ranging from 0.055 (resistant) to 0.930 (susceptible).
DNA samples from BC2
F1
 population were analyzed for genes and markers association; Ty-2 on chromosome 11 using AVRDC
primer number 11-090.0 (TG105A), and Ty-3 on chromosome 6 using marker C2_At3g11210. Results showed that Ty-2 was
lost during stepwise selection at BC₁
F₁
 generation, while Ty-3 showed no relationship to marker C2_At3g11210 and the
amount of virus detected from ELISA reading. This indicated that the TYLCTHV-[2] resistant phenotype response in the
BC₂
F₁
 population neither came from Ty-2 nor linked to the Ty-3 gene.