Genetic Variation in in-Vitro Cultures and Regenerated Plants in Tomato and its Implications

Abstract

Research activity on cell or tissue cultures and cytogenetics of in vitro differentiation in tomato dates, back to the early 1970’s. During the first period, investigations have been mainly focused on anther or pollen cultures, aiming at the production of haploids in both Lycopersicon esculentum (Sharp et al. 1971, 1972; Gresshof and Doy 1972; Debergh and Nitsch 1973) and L. peruvianum (Devreux et al. 1975, 1976; Sree Ramulu et al. 1976a,b). L. peruvianum is a very important species for tomato breeding, because it constitutes a rich source of disease resistance and of variations in morphological, physiological and floral biological traits as well as adaptability. However, it is self-incompatible, and unilaterally cross-incompatible with L. esculentum. Therefore, many studies have been directed towards the genetic aspects of self-incompatibility and incongruity in inbred and outcrossed progenies as well as in cell or tissue culture-derived plants, and the recovery of hybrid or backcross derivatives (Hogenboom 1972a,b: de Nettancourt et al. 1974; de Nettancourt 1977; Sree Ramulu et al. 1977; Cappadocia 1979; Cappadocia and Sree Ramulu 1980; Ancora and Sree Ramulu 1981; Thomas and Pratt 1981). At the same time, efforts were continued with L. esculentum, the interspecific hybrid (L. esculentum × L. peruvianum) and its derivatives to regenerate plants from various explant sources (see review Kut et al. 1984; Imanishi 1989).