EFFECTS OF GROWTH REGULATORS AND MULCHING ON TOMATO YIELDS

Abstract

The use of clear polyethylene mulch greatly increased the total yield of transplanted New Yorker tomatoes. The growth retardant succinic acid 2,2-dimethylhydrazide (SADH) applied pretransplant at the three- to four-true leaf stage retarded earliness, concentrated ripening, and increased yields slightly. Another growth retardant, (2-chloroethyl) trimethylammonium chloride (chlormequat), reduced the size of the plants appreciably, increased earliness slightly, but significantly reduced total yields. Concentrated ripening of fruit was obtained 6–9 days after (2-chloroethyl) phosphonic acid (ethephon) was sprayed on tomato plants. The high concentration of 4000 ppm of this chemical reduced total yields and size of fruit appreciably. At 1000 ppm, ethephon produced an initial peak of fruit ripening but since plants were not destroyed, they produced another peak of ripe fruit later in the season.