New varieties of tomato - morphological aspects and molecular characterisation with RAPD and SSR markers

Abstract

This study presents the main morphological features and the first molecular investigations of four new tomato varieties (Solanum lycopersicum), aiming to obtain their complete characterisation. Evaluation with the standard descriptors for tomato revealed specific and distinct traits for each analysed variety. The molecular analyses for variety identification started with testing three methods for DNA extraction. With an optimized method, which doesn’t need liquid nitrogen for plant tissue disruption, good quality DNA was obtained, in adequate quantities, and well preserved when stored at -20 °C. To highlight the genetic differences among the analysed tomato varieties, nine RAPD primers and ten SSR primers were tested. Of these, the optimal amplification protocols for five RAPD primers and five SSR primers were established. The amplified products obtained with RAPD primers revealed an average number of bands per primer of 8.8 and a total rate of polymorphism of 59.1%; with OPB10 primer was seen the highest number of DNA bands (11), and with OPA07 primer was registered the highest degree of genetic variability among the studied varieties (77.7%). Two SSR markers (SSR 20 and SSR T107) amplified monomorphic banding patterns corresponding to 170 base pairs and 250 base pairs, respectively, for all varieties; with SSR T7, SSR T62, and SSR T70 primers were generated multiple amplification bands, with a different distribution of the bands into the agarose gel for each analysed tomato variety.