GENETIC-CONTROL OF FRUIT SUGAR ACCUMULATION IN A LYCOPERSICON-ESCULENTUM X L-HIRSUTUM CROSS

Fruit of the cultivated tomato (Lycopersicon esculentum Mill.) store p redominantly glucose and fructose whereas fruit of the wild species L. hirsutum Humb. & Bonpl. characteristically accumulate sucrose. Reduci ng sugar and sucrose concentrations were measured in mature fruit of p arental, F-1, F-2, and backcross (BC1) populations derived from an ini tial cross of L. esculentum 'Floradade' x L. hirsutum PI 390514. Gener ational means analysis demonstrated that additive effects were equal t o dominance effects for percentage of reducing sugar. It was determine d that a single major gene, dominant for a high percentage of reducing sugar, regulates the percentage of reducing sugar in tomatoes. We pro pose that this gene be designated sucr. Only additive effects were dem onstrated to be important for glucose : fructose ratios. Using L. hirs utum as a donor parent for increasing total soluble solids concentrati on in the cultivated tomato is discussed.