Biotechnology and Abiotic Stress Tolerance in Rice

World population is escalating day by day and by 2050 it is expected to reach 9.1 billion, but agricultural production is not rising at a parallel pace. In order to feed the world population, global agricultural production should be increased by 60-110 per cent and 70 per cent more food for an additional 2.3 billion people by 2050 [1,2]. Agriculture production is dwindled mainly due to biotic and abiotic stresses. Abiotic stress is one of the major factors which negatively affect the crop growth and productivity world-wide. Hence, these are one of major area of concern to fulfill the required food demand [3,4]. The major abiotic stresses worldwide causing risks to food security are high salinity, drought, submergence and cold [5,6]. Among these stresses, drought is the first environmental stress responsible for decrease in agricultural production worldwide and to fulfill the demand, tons of efforts are being applied to improve crop yields [7,8]. Drought affects plants in countless ways like it affects plant growth, yield, membrane integrity, pigment content, osmotic adjustments, water relations and photosynthetic activity [9]. Salinity is the second most prevalent soil problem in rice-growing countries after drought [10] and rice is considered as a salt sensitive crop in early seedling stages [11] which limits its productivity [12,13]. Among 130 mha of world rice area, approximately 30 per cent area contains salt levels too high to allow normal rice yield. The decline in rice yield under reasonably salt-affected soils is anticipated to be 68 per cent [14]. Due to global warming, rise in sea levels, surplus irrigation without appropriate drainage in inlands and underlying rocks rich in detrimental salts, area under salt stress is growing. It is expected that if present scenario persists, 50 per cent of current cultivated land will be loss for agriculture by 2050 [15]. Cereals are the most significant source of calories to humans. Rice, wheat and maize offer 23%, 17% and 10% calories globally [16]. Rice (