V. NIKOLOVA and D. GANEVA
Maritsa Vegetable Crops Research Institute, BG - 4003 Plovdiv, Bulgaria
NIKOLOVA, V. and D. GANEVA, 2005. Study of pollen fertility in hybrid and backcross progenies on the basis of nuclear male sterility in tomato (Lycopersicon esculentum Mill). Bulg. J. Agric. Sci., 11: 661-666
The main purpose of the heterosis breeding in species Lycopersicon esculentum Mill is a creation of lines - double recombinant between genes determining male sterility and marker genes with phenotypic manifestation in early stages of ontogenesis. Breeding for creation of new male sterile tomato lines on the basis of gene ms1035 and of marker gene a, determining a degeneration process during the microsporogenesis and respectively the lack of anthocyan in the plant
stem, was carried out in the Maritsa Vegetable Crops Research Institute, Plovdiv The purpose of the performed investigation was to be studied some aspects of the expression of ms1035 and Ms genes, determining the male sterility and respectively pollen fertility, in segregation progenies of hybrids of line № 6944aa (msms1035aa) with variety Plovdivska carotina and Line № 1 and in their backcrosses - BC1P2 and BC2P2,
In F1 and F2 progenies of the hybrids with male sterile mother component (line № 6944aa) the gene Ms incompletely dominates over the recessive gene ms1035 in the heterozygous genotypes (Msms1035). The ratio fertile: sterile plants in F2 progeny of the studied hybrids are approximately 3: 1, as a part of the recessive homozygotes are lethal in different stages of embryo- or ontogenesis. In first and second backcrossing with the fertile P2 parents - variety Plovdivska carotina and Line № 1, the expression of the dominant gene Ms is stronger depressed in the heterozygous individuals.