THE EVALUATION OF WATER STRESS IN MAIZE (ZEA MAYS L.) USING SELECTION INDICES

Drought is one of the major problems that affect crops, including maize, in the Romanian region of Oltenia. As a result, the identification of maize hybrids with high yielding potential and drought tolerance are important breeding objectives. In order to identify such maize hybrids 20 Romanian maize hybrids were studied in yield trials at the Agricultural Research and Development Station (ARDS) of Simnic, during three years (2003-2005) at different water availability conditions (irrigated and non-irrigated) in randomized blocks, with three replications. In order to evaluate the drought tolerance/susceptibility, six indices of selection were used: mean productivity (MP), geometric mean productivity (GMP), stress tolerance (TOL), stress susceptibility index (SSI), stress tolerance index (STI) and harmonic mean (HAR). The best indices for both conditions (irrigated and non-irrigated) proved to be MP, GMP, STI and HAR. The TOL and SSI were good predictors for non-irrigation conditions only. The tolerance of the researched hybrids depended on the severity of the water stress. The following hybrids were the most tolerant at severity water stress (SI = 0.78): Neptun, Oana, Ileana, Rapsodia, Campion and Cocor.