Irrigation with brackish water under desert conditions XI. Salt tolerance in sweet-corn cultivars

The salt tolerance of 14 sweet corn (Zea mays L.) cultivars differing in days for silking and days for grain filling was evaluated under field conditions in an arid environment. Plants were drip irrigated with fresh (EC_i=1.2 dS m^-1) and brackish (EC_i=6.2 dS m^-1) water. Brackish water irrigation started 20 days after planting following the application of 100 mm of fresh water. There were large intraspecific variations in absolute yield and in salt tolerance (expressed as the ratio of brackish water yield to fresh water yield). The cultivar N.K Rogers 2572 had, under saline conditions, both the highest absolute ear yield (18.1 kg per 10 m²) and the highest relative ear yield (82%). Salinity affected all major yield parameters (number of ears per unit area, number of kernels per ear and kernel weight). Ear number was more affected than other parameters. Results indicate that early flowering cultivars are, under the irrigation regime employed in the trial, more salt tolerant than late flowering cultivars. Salinity had an inconsistent effect on kernel quality parameters. In some cultivars it increased soluble carbohydrates and sucrose contents, while in others these parameters were reduced.