DROUGHT TOLERANCE OF MAIZE PLANTS OBTAINED FROM THE CELL-LINES RESISTANT TO OSMOTIC-STRESS PRODUCED BY POLYETHYLENE-GLYCOL

The feasibility of the method of cell selection for breeding drought-r esistant cultivars of maize (Zea mays L.) was investigated. Resistant cell lines were selected from the callus tissue obtained from the imma ture embryos of the hybrids Chinese 31 x Tuxpeno Norteno and Chinese 3 1 x Cateto Sulino Grosso using a medium containing 25% polyethylene gl ycol. Water-holding capacity and heat resistance were estimated in the leaves of the seed progenies (R1) obtained by the self-pollination of eight regenerants. The cell selection provided plants with enhanced h eat tolerance expressed during vegetative growth and tasseling under c onditions of insufficient and optimal watering. The maximum increase i n the water-holding capacity in the R1 families under study was observ ed during anthesis. In contrast to the initial maize genotypes, drough t did not impede flowering in the selected forms. The expression of dr ought resistance in the seed progeny of regenerated plants indicates t hat there is a genetical control over this trait.