MOLECULAR MARKER SCREENING FOR TY-2 GENE IN TWO TOMATO GENOTYPES SOLANUM LYCOPERSICON L.

Tomato yellow leaf curl virus TYLCV is a major tomato virus in tropical and subtropical regions. The resistance to TYLCV disease in the tomato accession FLA456 and the breeding line CLN2498E was analysed by screening the parents F1 and BC1F1 population using a sequence tagged site STS marker linked to Ty-2 gene T0302 at the Biotechnology and Molecular Breeding Unit of the Asian Vegetable Research and Development Centre AVRDC the World Vegetable Centre at Taiwan. Results showed that CLN2498E carried Ty-2 gene and FLA456 did not carry it. The BC1F1 plants segregated for Ty-2 gene in a ratio of 4666 which is closed to 11 9673.33 P 0.05 which indicated that Ty-2 gene was simply inherited. The phenotypic screening showed that the breeding line CLN2498E was susceptible to TYLCV-Thailand strain although it carried the Ty-2 locus. The accession FLA456 was tolerant to TYLCV-Thailand strain. Although the F1 plants carried the Ty-2 locus with heterozygous alleles they showed tolerance to TYLCV-Thailand strain disease. All the plants in the BC1F1 bearing the two bands 900 bp and 800 bp were tolerant to the disease while others with only 900 bp were susceptible. The results concluded that CLN 2498E carries Ty-2 gene and does not resistant to TYLCV-Thailand strain whereas FLA 456 does not carry Ty-2 gene and resistant to TYLCV-Thailand strain.