Effect of chlormequat chloride, ß-naphthoxyacetic acid and ethephon on early and total yield of tomato in open field

Tomato seedlings in hotbed with Antywylegacz (chlormequat chloride) to suppress their excessive elongation before transplanting, were used. Their first 2-3 flower clusters were dipped in the field in Betokson (ß-naphthoxyacetic acid) to induce better early fruit set and the plants were sprayed with Ethrel (ethephon) just before the first fruits become pink, to stimulate earlier ripening and increase early yield. The experiment was carried out during 3 years with the cultivars 'Venture', 'New Yorker' and 'Nesthackchen' (only in 1975). Application of chlormequat alone prevented excessive growth of the seedlings but did not increase early yield significantly. ß-naphthoxyacetic acid alone was effectiveevery year and always increased early yield. Chlormequat followed by ß-naphthoxyacetic treatment showed always a tendency to increase early yield more than ß-naphthoxyacetic acid alone. Treatment with ß-naphthoxyacetic acid, alone or in combination with other treatments, lowered the total yield. Ethephon used solely or in combination with other treatments usually was ineffective.