Effect of Foliar Spray of Chemicals on Flowering and Fruiting in Litchi

Abstract

A field experiment was conducted to induce the flowering in litchi through pre-flowering spray of different potassium forms application i.e. di-potassium hydrogen-ortho-phosphate (dibasic), potassium di-hydrogen orthophosphate (monobasic), potassium nitrate and a PGR i.e. 2-Chloroethyl phosphonic acid (ethrel) in 9-10 years old litchi orchard consecutively for 2 years. The four spraying of each chemical was applied during October – January at monthly interval. These chemicals significantly influenced the flowering and fruiting characters. The ‘Shahi’ litchi trees sprayed with 1% mono-potassium phosphate and 400 ppm ethrel increased flowering percentage. Ethrel (400 ppm) sprayed not only advanced flowering and harvesting by 6-7 days but also recorded maximum yield (70.48 kg per tree) due to highest record of number of female flower per panicle and improved the fruit quality in terms of total soluble solids (20.47 0B) and TSS/Acid ratio. Combined spray of 1% mono-potassium phosphate and 1 % potassium nitrate led to highest fruit weight, pulp recovery, female flower per panicle and sex ratio (1.03). Spray of 1 % potassium nitrate led to largest fruit and seed weight and most of the fruits were >21 g in weight which is most desirable characters to fetch premium price by the litchi growers. Untreated trees merely had fruit weight <18.0 g and fruit yield per tree only upto 33.70 kg per tree also had least acidity percentage. In this investigation, it is indicated that, foliar spray of different forms of potassium and ethrel improved flowering and final fruit yield in litchi trees.