Development of tomato hybrid aiming to pyramid Ty genes for imparting tolerance to tomato leaf curl virus disease

ABSTRACT

Development of tomato hybrids with stable tolerance against tomato leaf curl virus (ToLCV) disease is necessary in the tropics and sub-tropics. Genotypes having a broad genetic base and phenotypic diversity were chosen as parents and crossed in a 4 × 3, line × tester fashion without reciprocals to produce 12 F₁ tomato hybrids to determine manifestation of heterosis and gene action for characters. The predictability ratio exhibited a desired response for non-additive gene action in controlling expression of most traits including percent disease index (PDI) of ToLCV, but not for days to first flowering, locule number, fruit pH, fruit lycopene content and fruit yield per plant which were controlled by both additive and non-additive gene action. Specific gravity, titratable acidity and polar diameter of fruit were controlled by additive gene effect. Maximum heterobeltiosis in the desired direction was recorded for fruit yield per plant followed by lycopene content of fruit, retinol activity equivalent, and PDI of ToLCV. Two genotypes, “AVTO-1315” and “2016 Res/1” were promising genitors and may be utilized in future breeding. Hybrids “AVTO-1424 × 16 RES 1” (Ty-2, Ty-3, ty-5 + Ty-2) and “AVTO-1315 × 2016 Res/1” (Ty-1/Ty-3, Ty-2 + Ty-2) carrying multiple genes were considered promising for high yield with some field tolerance against ToLCV disease. Pyramiding multiple genes possessing at least Ty-2 and Ty-3 into tomato hybrids may be effective in managing ToLCV disease for tropical and subtropical regions.

KEYWORDS:

• Solanum lycopersicum
• combining ability
• gene action
• heterosis

Acknowledgments

We thank the Asian Vegetable Research and Development Centre, Taiwan, for providing genetic materials to carry out this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).