IMPROVEMENT OF SALT TOLERANCE IN MAIZE BY SELECTION AND BREEDING

Genetic variation for NaCl tolerance at the vegetative stage was assessed in nutrient solution culture in maize (Zea mays L.). Shoot growth, and plant fresh and dry weight of the two cultivars, Akbar and Sadat were severely reduced after three weeks growth in 120, 150, and ISO mol m−3 NaCl. There was however considerable variability between seedlings. Ten‐thousands seeds of cv. Akbar were therefore screened for shoot growth at 180 mol m−3 NaCl after four weeks growth in sand culture. A selection intensity of 0.42 % was achieved. Eighteen selected plants were polycrossed for estimation of narrow‐sense heritability based on female parent‐progeny regression. A narrow‐sense heritability estimate of 0.54 was obtained. The progeny of the salt‐tolerant selection line and selfed progeny plants of the unselccted control lines of cvs Akbar and Sadat were grown for six weeks in 0, 30, 60, 90, 120, 150, and 180 mol m−3 NaCl in sand culture. The tolerant line produced significantly greater fresh and dry biomass and had greater shoot length than the unselected cv. Akbar, but the selection line derived from cv. Akbar was equal to the salt tolerant cv. Sadat in all the growth parameters measured. These data suggest that in maize, improvement in salt tolerance could be obtained through further cycles of selection and breeding. Copyright © 1990, Wiley Blackwell. All rights reserved