Improvement in yield, quality and reduction in fruit drop in kinnow (Citrus reticulata Blanco) by exogenous application of plant growth regulators, potassium and zinc

摘要

Kinnow (Citrus reticulate Blanco) fruit is one of the best commercial fruits of Pakistan. It is cultivated on a large area in the Punjab province due to its reasonably higher yield, quality, taste and flavor than those of the other citrus fruits. However, its average yield in Pakistan is far below than that of the other citrus growing countries of the world. Fruit dropping is one of the main reasons of low citrus fruit yield in Pakistan, which is thought to be mainly due to hormonal imbalance in the plants. This imbalance may occur as a result of nutrient deficienc y in orchard soils, water shortage, and insect pest attack on the citrus trees. Therefore, experiments were conducted to assess the influence of growth regulators [2,4-D and salicylic acid (SA)] and nutrients [potassium (K) and zinc (Zn)] to improve yield and quality of Kinnow fruit and control the fruit drop at four selected sites in the citrus growing tract of Punjab, Pakistan. Foliar applications of 2,4-D, SA, K, and Zn significantly improved the fruit weight, number of fruits per plant juice percentage, total soluble solids (TSS), ascorbic acid content, acidity, and TSS/acid ratio, and reduced the fruit drop. Application of 2,4-D+K+Zn and SA+K+Zn showed beneficial effects on all the afore-mentioned parameters.