Crop regulation in guava through different crop regulating treatments.

摘要

The effects of sprays of ethephon (600, 1200 or 1800 ppm), NAA (200, 400 or 600 ppm), urea (10, 15 or 20%) or potassium iodide (0.5, 1 or 2%), applied at flowering in April and again 2 weeks later in May, on flower drop and fruit yield of guava cv.Allahabad Safeda were investigated at Lucknow, India. Pruning (50, 75 or 100%) of current season's growth was performed on 10 May. Some of these treatments induced complete abscission of leaves and/or flowers which reduced fruit yield during the rainy season. In the rainy season, the highest yield (16.18 kg/plant) was obtained from 50%-pruned plants, and the lowest yields (0 kg/plant) were obtained from plants treated with urea at 20%, potassium iodide at 1 or 2% and those pruned 100%. In the winter season, plants receiving 10% urea produced the highest yield (84.81 kg/plant) and those treated with urea at 20% produced the lowest yield (11.17 kg/plant). In comparison, untreated control plants yielded 31.76 and 25.83 kg/plant in the rainy and winter seasons, respectively. These treatments did not significantly influence fruit quality (weight, size, TSS, pH or ascorbic acid content) but did have a significant effect on percentage total sugar content.