Use of Growth Retardants to Improve Ripening Uniformity and Yield of Processing Tomatoes

Abstract

Abstract After the major fruit set period was completed, aqueous sprays of 1000 ppm dikegulac, 66 ppm ancymidol, 1000 ppm maleic hydrazide (MH), and 1 kg·ha−1 RSW 0411 were applied to processing tomato (Lycopersicon esculentum Mill) plants. Dikegulac, RSW 0411, and ancymidol visually reduced vegetative growth, whereas MH had no apparent influence. None of the compounds reduced the number of flower clusters or flowers per cluster on the late-season growth, but dikegulac and RSW 0411 did reduce the percentage of fruit set in the terminal regions. The partial reductions in late vegetative and/or reproductive growth from the chemical treatments did not enhance uniformity of fruit maturity. Only the dikegulac treatment decreased the yields and percentage of green fruit from the harvest. Chemical names used: 2,3:4,6-bis-O-(1-methylethylidene-d-l-xylo-2-hexulofuranosonic acid (dikegulac); α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); 1,2-dihydro-3,6-pyridazinedione [maleic hydrazide (MH)]; and β-(cyclohexylmethylene-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (RSW 0411).