EFFECT OF DROUGHT AS A STRESSING FACTOR ON THE FLOWERING OF 2 MAIZE LINES

The aim of the experiments was to determine the effect of drought stre ss during various phases of maize flowering on the flowering and physi ological processes of plants in phytotron climate chambers. The follow ing conclusions were drawn: It was found that the male flowering of th e earlier maize line (Mo 17/Mv) became 10 days earlier, and the female flowering time 6 days earlier than in plants under field conditions. In the case of the later maize line (HMv 5502) these figures were even greater, being 13 and 10 days. The water potential of the ear decreas ed more drastically as the result of drought stress than that of the s ilk which is less susceptible to drought due to the protection provide d by the ear leaf. Drought may cause irreversible damage to the flower ing processes. It was found that six days of drought stress following tasselling led to a substantial reduction in the pollen fertility of t he tassels. The responses of the maize genotypes were different. As th e result of drought stress changes were observed in a number of chloro phyll fluorescence induction parameters. These changes were greater in Mol 7/Mv than in HMv 5502. The later line is considerably more tolera nt of drought: stress than Mo 17/Mv.