Role of Allelopathy in vegetables crops production

Vegetables are important worldwide, but their production faces problems of yield decline due to soil sickness and autotoxicity, when grown continuously for several years. Besides, allelopathic effects of other crops, weeds and trees also reduces yields. Thus the allelochemical interactions and their effects on vegetables are important in vegetable production. Although, research on various aspects of allelopathy in vegetable crops has been done but not compiled. Soil sickness is complex phenomenon due to several factors involved and autoxicity is major one. The autotoxic potential of certain vegetables has been discussed. In multi-storey cropping systems, where numerous crops and trees are grown together, vegetables are essential components and allelopathic interactions arise. Several vegetables possess antimicrobial principles and hence, allelopathically inhibit phytopathogenic fungi and bacteria. Certain vegetables possess nematicidal principles and therefore, offer immense potential for nematode control in their cultivation. Several studies have been done to elucidate the role of allelochemicals in vegetables across the world. The allelopathic interactions between the vegetables and other crops/weeds/trees and the potential of vegetables for pathogen and nematode management/control are reviewed in this paper. Future allelopathic research in vegetables should focus on (i) separating the allelopathic interference from competition in vegetable fields and vegetables based cropping systems, (ii) screening the germplasm/varieties of vegetable crops for allelopathic potential and later on do genetic manipulations to breed new varieties. (iii) exploiting the allelopathic potential of vegetable crops for weed control and plant protection, (iv) determining the critical concentrations of allelochemicals in each vegetable crop to express their inhibitory/stimulatory influences, (v) identifying the compatible and beneficial associations of vegetable crops with other crops and trees and (vi) determine the harmful and beneficial effects of allelopathy in vegetable crops in pot culture and field studies.