OSMOTIC ADJUSTMENT IN MAIZE (ZEA-MAYS L.) - CHANGES WITH ONTOGENY ANDITS RELATIONSHIP WITH PHENOTYPIC STABILITY

Genetic variation for osmotic adjustment was examined in a group of ma ize hybrids during vegetative and silking stages. Estimates of osmotic adjustment were derived from measurements of leaf relative water cont ent (RWC) and osmotic potential (psi/0) before day-break. The degree o f adjustment was estimated from the In RWC/ln psi/o relationship. All cultivars examined showed some degree of osmotic adjustment and signif icant differences (P < 0.05) were found among them. The utility of mea surements in early vegetative stages as a mean of selection for osmoti c adjustment in silking stage was established. A positive tendency was observed between osmotic adjustment and phenotypic stability.