The relationship between seedling growth and grain yield under drought conditions in maize and triticale genotypes

The effects of drought stress on seedlings’ growth and grain yield of 13 single cross maize hybrids and 11 breeding lines and cultivars of spring triticale were studied in greenhouse and field experiments. In the field experiment, the drought susceptibility index (DSIGY) was calculated by determining the change in grain yield (GY) in conditions with two soil moisture levels (IR, irrigated; D, drought). In the greenhouse experiment the response to soil drought was evaluated using DSIDW, by determining changes in the dry weight (DW) of vegetative plant parts. Marked variations in GY and DW were observed among the studied genotypes. In control conditions, the GY and DW in drought-sensitive genotypes were higher compared to the drought-resistant ones; but in drought conditions, the decreases in GY and DW in resistant genotypes were smaller than in drought-sensitive ones. DSIGY and DSIDW revealed variations in the degree of drought tolerance among the examined maize and triticale genotypes. The values of DSIGY in the field experiment and DSIDW in the greenhouse experiment enabled a division of the studied genotypes into drought-resistant or -sensitive groups. A close correlation between DSIGY and DSIDW was found. The positive linear correlation and determination coefficients between DSIGY and DSIDW were statistically significant (P = 0.05), being equal to R2 = 0.614 (maize) and R2 = 0.535 (triticale). The ranking of the studied genotypes based on DSIGY was in most cases consistent with the ranking based on DSIDW, which indicates that genetically conditioned drought tolerance is similar for plants in the seedling and reproductive growth stages or may at least partly have a common genetic background.