Characterization and screening for leaf curl disease resistance in natural variants of tomato (Solanum lycopersicum) genotypes

Abstract

The experiment was conducted during winter (rabi) seasons of 2022 and 2023 at ICAR-Indian Agricultural Research Institute, Pune, Maharashtra to evaluate the natural variants of tomato (Solanum lycopersicum L.), PTS-8, PTS-25 and PTS-29, isolated from Pusa Gaurav and EC538421. The identified line evaluated along with parental lines (Pusa Gaurav and EC-538421); PTS-24; Pusa Rohini and Arka Rakshak for morphological characterization and tomato leaf curl virus (ToLCV) incidence. Plant height ranged from 41.35–144.33 cm and early flowering (30–33 days) was observed in lines, PTS-24, PTS-25, and PTS-29. Large sized fruits (72–76 g) were recorded in PTS-8 and PTS-25, while highest yield (138.65 t/ha) was recorded in PTS-25. PTS-24 and PTS-25 recorded low seed content of 0.28 g and 0.37 g/100 g fresh fruit, respectively which is desirable for utility in processing industry and for raw consumption. Highest vitamin C content (38.87 mg/100 g FW) was observed in PTS-24. Incidence of ToLCV was lowest in PTS-8 (5.33%), followed by EC538421 (6.25%), PTS -29 (6.61%) and Arka Rakshak (6.93%). Pusa Rohini was most susceptible line (48.42%). All the lines were screened for leaf curl, CMV and aphid/nematode resistance/ tolerance markers with 12 different primers. Line EC538421, its variants PTS-8, PTS-29 and Arka Rakshak showed amplification of resistant fragment (900 bp, T0302 primer) for ToLCV resistant marker Ty-2. All the lines were tested negative for other resistance markers. Principal component analysis revealed that traits such as number of fruits/plant, yield, disease intensity, seeds/fruit etc. were some of the principal discriminatory characteristics. These identified lines can be utilized in breeding programmes to develop improved tomato cultivars.