Development/selection of salinity and waterlogging tolerant wheat genotypes

Salinity and waterlogging are having substantial adverse social and economic effects in many and and semiarid regions that are irrigated. In Pakistan, apart from a few localized areas, salt-affected soils are confined to the Indus Plain. In addition to this, waterlogging is a serious problem affecting irrigated agriculture in the Indus Plain and about 13% of the area in Pakistan has a high water table (0-150 cm) which enlarges to 26% after monsoon rains. In rice tract or sods having dense structure due to relatively high clay contents and other salt-affected areas having associated problem of waterlogging, the wheat crop typically suffers a dual stress of oxygen shortage and moderate salinity. Since many of these soils are beyond the reach of conventional reclamation techniques, either for economic reasons or for the lack of fresh water, a major scientific thrust has been aimed at developing suitable salt- and waterlogging-tolerant crops to bring these lands into agricultural productivity. In this respect, an understanding of the plant responses to various stresses and the mechanisms that make some species or genotypes more tolerant than others seems essential. Keeping these objectives in mind, Saline Agriculture Research Cell (SARC) started a screening and stress breeding programme a decade ago and conducted various studies in the laboratory, green house and in the farmer's fields on wheat and wheat-Thinopyrum amphiploids. In this paper, findings of these studies including the response of wheat and wheat-Thinopyrium amphiloids and potential useful mechanisms which might helped these genotypes to grow and produce more economic yield under saline and waterlogged conditions are discussed.