Theor Appl Genet (1989) 78:836-840 9Springer-Verlag 1989 In vitro culture of Cucumis sativus L. 7. Genes controlling plant regeneration A. Nadolska-Orczyk *'** and S. Malepszy Department of Genetics and Breeding of Horticultural Plants, Warsaw Agricultural University, Nowoursynowska 166, 02-766 Warszawa, Poland Received December 20, 1988; Accepted August 9, 1989 Communicated by Yu. Gleba Summary. The ability to regenerate plants from leaf ex- plants has been tested for three highly inbred cucumber lines (B, G, S), their reciprocal hybrids, F 2 and BC 1 generations. The lines differed from each other in their regenerating ability, which was expressed by the percent- age of explants regenerating embryoidal callus and mean number of plantlets per plant. Thus, the lines could be classified as frequently (B), intermediately (G) or occa- sionally regenerating ones (S). There were no reciprocal cross differences in the regeneration. It was found that the intermediately and intensively regenerating lines con- tain two pairs of dominant genes responsible for plant regeneration, characterized by complementary and prob- ably additive interaction. The frequently regenerating line differed from the intermediately regenerating in the effect of one gene. It is supposed that the above-men- tioned genes belong to three different loci. The ability to regenerate plants from leafexplants had high heritability. Key words: Genetic control of regeneration - Cucumis salivus Introduction The effect of genotypes on the results of culture is observ- able in both monocotyledons and dicotyledons. It was proven that a genotype could control various stages of in vitro culture, namely: anther callus development (Miah et al. 1985; Rines 1983), intensive callus growth (Sharma et al. 1980), induction of callus (Nesticky etal. 1983; * Present address: Plant Breeding and Acclimatization Insti- tute, Radzikow, 05-870 Blonie, Poland ** To whom correspondence should be addressed Tomes and Smith 1985) embryoid development (Brown and Atanassov 1985), plant regeneration ability (Sharma et al. 1980; Abe and Futsufara 1984; Kurtz and Line- berger 1983) and plant regeneration in long-term culture (Malmberg 1979; Locky 1983). It was discovered for Medicago sativa that as a result of cyclic selection, genes responsible for plant regenera- tion were cumulated. This caused a considerable increase in the number of regenerated plants (Bingham et al. 1975). Due to gene complementation and segregation, more advanced developmental stages of embryoids can be obtained in anther culture of potato (Jacobsen and Sopory 1978). In a number of studies, the cultivar differ- ences were analyzed by comparing hybrids with their parents (Ohki etal. 1978; Frankenberger et al. 1981; Charmet and Bernard 1984; Nesticky et al. 1983; Tomes and Smith 1985). Only a few papers have proposed in detail the mode of inheritance of regeneration ability using F 1, F2 and BC1 generations (Reisch and Bingham 1980; Broda 1984; Koornneef et al. 1987). It was shown that cucumber lines and varieties differ from one another in their plant regeneration ability using hypocotyls and cotyledons (Wehner and Locy 1981) and leaf explants as well (Malepszy and Nadolska-Orczyk 1983). This paper contains analysis of inheritance of plant regeneration ability. On the basis of the observation of F1, F 2 and BC 1 generations, we suggest the mode of interaction among genes controlling this trait. Materials and methods Three highly inbred lines (I1~), their reciprocal hybrids and F2 generation were used for the experiments. The parents used in the crosses were: S - obtained from Skierniewicki female, par- thenocarpic greenhouse variety, B - developed from Borszcza-