Pre-mature fruit drop and coffee production in India: a review

Abstract

Coffee is a stimulating beverage crop and finds second place after petroleum products in the world trade. There are many species of coffee but only two species, Coffea arabica and C. canephora popularly called as arabica and, robusta coffees are commercially cultivated. The pre-mature fruit drop of 6–10 % occurs during early stage of berry growth and development in June–July, which is a common phenomenon due to various reasons irrespective of the crop season. However, certain pre-disposing factors such as wet feet condition due to excess rain fall coupled with cool ambient temperature, high relative humidity, cloudy weather and inadequate drainage leading to soil saturation and water logging, improper handling of bushes facilitating the secondary infection of stalk rot and black rot increases the pre-mature fruit drop. In general, fruit drop in coffee is not common at maturity/ripening stage unless the winter period that coincides with ripening stage experience heavy rain fall and hail storms leading to splitting and dropping of ripened fruits. Physiological pre-mature fruit drop under ‘Wet feet’ conditions, is associated with reduction in endogenous levels of cytokinins coupled with high content of abscisic acid (ABA) and reduction in carbohydrate reserve and nutrients. The competition among the different-sized developing berries for carbohydrate reserves causes’ additional drop of pre-mature berries. Plants bearing high number of berries are also vulnerable for high percentage of fruit drop due to competition among the developing berries for carbohydrate reserves and nutrients. Systematic studies have revealed that physiological intervention by use of plant growth regulators, coupled with adoption of good agronomic practices, reduces pre-mature fruit drop and defoliation, and enhance cropping wood for subsequent year, resulting in increase in crop yield by 12–20 %. Here we have reviewed physiology aspects associated with pre-mature fruit drop, pre disposing factors for defoliation and pre-mature fruit drop, use of plant growth regulators to minimize the losses and role of recommended cultivation practices for realizing yield potential.