Pigment composition of fruits in solanum lysopersicoides hybrids

Chalukova, M., Stoeva, P., Vulkova-Achkova, Z. Maritza Institute for Vegetable Crops, 32 Brezovsko shosse str., Plovdive-4003, BULGARIA

Fertile tetraploid hybrids of the cross F1 (L. esculentum v. cerasiforme x L. esculentum) x S. lycopersicoides (Stoeva et al. 1990) were developed by tissue culture methods. The pigment composition of the parents and of FI, F2 and F3 hybrids was studied in order to assess the genetic potential of S. lycopersicoides in respect to carotenoid production. Caratenoids were separated by column chromatography on aluminum oxide and their quantity was determined spectrophotometrically.

Hybrid fruits of the three generations had the same orange-green color. Phenotypic uniformity of the hybrids for other characters such as shape and size of flowers, etc. (Stoeva et al. 1990) was also observed, which is not typical for segregating generations in remote hybrids. The similar appearance in fruit color of all hybrids investigated was due to the similarity of their carotenoid composition - their number of pigments was equal and variation in the quantitative content of individual carotenoids was slight (Table 1).

S. lycopersicoides dominated in the inheritance of total carotenes, phytofluene and lycopene, beta-carotene content in hybrid fruits was higher than that in parent forms. This fact gives grounds for the presumption that a gener similar to the gene B in tomato is present in S. lycopersicoides . No delta-carotene was found in hybrid fruits, despite precise rechromatographing of the pigment fractions. It is possible that the delta-carotene gene is not present in the S. lycoprsicoides genome. Green fruited wild tomato species are carriers of this gene (Chalukova, Stoeva, 1988). Further studies are necessary to assess with complete certainty the presence of B and Del genes in S. lycopersicoides. Such studies, however, are rendered difficult by the fact that fertile hybrid plants are very rare.

S. lycopersicoides fruits contain an unidentified carotene X-453, which was present also in hybrid fruits of green fruited tomato species (Chalukova, Stoeva, 1982). The relatively high content of xanthophyllis in S. lycopersicoides hybrid fruits is remarkable. Probably it is the result of more active processes of hydroxylation and epoxidation of carotenes, of higher solids content in the fruits and of the prolonged period of fruit ripening.

Table 1. Carotenoid content in the fruits of parent forms and hybrids from the cross F1 (L. esculentum v. cerasiforme x L. esculentum) x S. lycopersicoides

Literature cited:

Chalukova, M., Stoeva, P. 1982. C.R. Acad. Bulgare Sci., 35:693-696.
Chalukova, M., Stoeva, P. 1988. Plant Breeding 100:230-234.
Stoeva, P.,Achkova, Z., Zagorska, N. 1990. Acta Horticultural, 280:475-478.