Fruit drop in cotton: some causes

Various aspects of fruit abscission in cotton have been reviewed in the past. Recent advances in this field thus permit consolidation of review of the current research. A major concern among cotton growers is heavy fruit drop, that leads to direct yield loss, which occurs at the expense of squares and young bolls. Shedding of fruiting forms in cotton is the combined consequence of plant itself like hormonal imbalance, plant nutritional status, age relation, and environmental stresses like water deficit, waterlogging, high temperature, dim light, salinity, insects and diseases. These stresses result in prominent signaling modifications like hormonal imbalance. Ethylene is claimed to play a key role in abscission apparently by activating the production of cell wall degrading enzymes such as cellulases and polygalacturonase. The premature dropping of fruiting bodies can significantly increase due to these environmental stresses, which result in severe loss in cotton yield. This article is focused on both internal and external factors that leads to fruit abscission, mechanism of fruit abscission at the physiological, hormonal, and molecular level and trying to point out the missing links on different aspects of plant hormones and environmental stresses regarding fruit abscission. This article also focused on the missing pieces of the very complicated puzzle of fruit abscission process in cotton and elucidation of the mechanism by which plants perceive abscission signals and trigger phytohormone–mediated signal transduction cascades is crucial to devise fruit shedding related breeding and transgenic approaches.