Allelopathy and abiotic stress interaction in crop plants

Global climate models predict the increase in daily mean temperature, changed patterns of precipitation, increase in episodes of drought, and floods in future, the abiotic stresses; all posing threats to crop production and food security. Plants have evolved several mechanisms to cope with abiotic stresses. Ecological interaction of production and release of secondary metabolites among organisms in ecosystems, the allelopathy, has been associated with the tolerance mechanism against abiotic stresses. Endogenous levels of secondary metabolites, defined as allelochemicals, have been taken as indices of abiotic stress resistance. Exogenous application of allelochemicals has been found to increase their endogenous level with simultaneous increase in growth and resistance against abiotic stresses. Identification of genes responsible for allelochemicals production, and development of transgenic crops with these genes is becoming an attractive option for improving resistance against abiotic stresses. In this chapter, the production of allelochemicals under abiotic stresses in plants, strategies to enhance their production, and role in improving resistance against abiotic stresses is discussed.