Search

The 'Tomato yellow leaf curl disease', caused by Tomato Yellow Leaf Curl Virus (TYLCV-IL [CU]) has caused extensive damage to tomato crops in Cuba. There are several resistance genes that have been introgresed to tomato from wild Solanum species. The objective of this study was to assess the segregation of two such genes, Ty-1 and Ty-2, as the basis for selection in improving resistance to TYLCV-IL [CU]. Two F2 populations, susceptible cultivar 'Amalia' x resistant cultivar 'H-24' (Ty-2), TY-2F2 and 'Amalia' x resistant cultivar 'LA3473' (Ty-1), TY-1F2, were obtained. Plants F2 and plants of susceptible controls, cvs. 'Amalia' and 'STY-1'. The plants, 25 days after sowing, were inoculated with viruliferous (Cuban isolate TYLCV-IL [CU]) whiteflies (Bemisia tabaci, biotype B) for 48 hours before transplantation to the field. The disease severity index (DSI, 0-4 scale) and viral DNA (dot blot hybridization) were evaluated 30 days after the inoculation. The plant frequency distribution of disease severity and viral DNA concentration changed according to TY-2F2 and TY-1F2 plants. Therefore, we should select as resistant plants to TYLCV those with 1 score in TY-1F2 and 0 scored in TY-2F2, when the improvement program is performed by selecting phenotypic resistance TYLCV-IL [CU] conferred by Ty-1 and Ty-2 resistance genes, respectively. [ABSTRACT FROM AUTHOR]

Tomato Yellow Leaf Curl disease is one of the most important problems affecting tomato cultivation in most part of the Cuban growing areas and in other countries. The casual agent is the TomatoYellow Leaf Curl Virus (TYLCV). At the moment several genes related with the resistance have been described. The genes Ty-1, Ty-2 and Ty-3 are those that more they have been used in the plant breeding programs of the species. In Cuba, Vyta is only variety that had Ty-1 gene and other accessions carrying the Ty-2 gene. The amplification of the gene Ty-3 was carried out for PCR and were used the specific primers FLUW-25R and FLUW-25F. In this work the presence of the band related with the resistant pattern of the gene Ty-3 was identified in one that six characterized accessions. [ABSTRACT FROM AUTHOR]