Influence of cytoplasm on in vitro regeneration capacity in hybrids and their segregating generations in tomato (Lycopersicon esculentum Mill)

Abstract

Three tomato cultivars (Lycopersicon esculentum Mill): Rossol Selección La Consulta (R); UC 82 (U) and Platauco INTA (P), their reciprocal crosses were studied for their shoot-forming capacity. Leaf explants were cultured in vitro on Murashige and Skoog (MS) medium with AIA 0.175 mg/L + BA 2.25 mg/L (M1) and with BA 1.125 mg/L (MII). Shoot-forming capacity was evaluated through two measures: the development rate (DR), proportion of explants with calli and/or shoots, and prolificity rate (PR), proportion of shoots to developed explants. No differences among cultivars were found in both media for DR and PR. In M1, significant differences between reciprocal crosses (R x U - U x R) were found for PR (t = 1.8; p < 0.05). F2 plants were obtained by selfing the F1 and 171 of the former had the U cytoplasm, while 85 had the R one. The U cytoplasm PR was 2.43 and R was 1.93 (t = 2.81; p < 0.01). These results would indicate that the cytoplasm effects on regeneration are still active in the F2 generation, since it can be inferred that the genetic variability for the regeneration ability might be inhibited by cytoplasmic effects.