EFFECTS OF ETHREL ON FRUIT AND SEED RELATED CHARACTERS IN 4 INBRED LINES OF CUCURBITA-MAXIMA DUCH

The effect of Ethrel (at 300 and 500 ppm concentrations) on four Cucur bita maxima inbred lines of good combining ability was tested for the following traits: period without male flowers, plant shape, fruit yiel d, seed yield, and 1000 seed weight as well as seed germination abilit y. Ethrel treatment inhibited male flower formation for 10-11 days at 300 ppm and 16 days at 500 ppm from the day of the first female flower anthesis depending on genotype. The latter period appeared to be suff icient for cross pollination between parental forms. The lines distinc tly differed in their reaction depending on Ethrel concentration and t he behaviour of each line was specific as regards particular traits. E threl treatment had high effect on fruit yield, seed yield, plant shap e, and size but low on 1000 seed weight. Seed germination ability rema ined unaffected and the first female flower development was just a lit tle earlier. The results obtained can be applicable in hybrid seed pro duction.