Determination of drought tolerances at early growingstages of some hybrid sweet corn (zea mays saccharata sturt.)candi̇date culti̇vars

In this study, drought tolerance levels (K1: 0% water restriction/CC/control, K2: 75% irrigation/%25 water restriction, K3: 50% irrigation/%50 water restriction, and K4: 25% irrigation/%75 water restriction) of five different sweet corn candidate hybrid cultivars (23-SCH-03, 23-SCH-07, 23- SCH-08, 23-SCH-12, and 23-SCH-23) were investigated. The research was carried out under greenhouse conditions in 11-liter capacity plastic pots, using a randomized split-plot design with three replications, with different drought levels forming the main plots and different cultivars forming the subplots. In the scale assessment created to determine the visual effects of drought stress, an increase in the stress level led to an increase in the scale value, i.e., an increase in the degree of damage, and this effect was particularly prominent in the K4 treatment. Especially under 25% limit irrigation conditions, 23-SCH-07 was determined to be the most susceptible variety to drought stress with a scale value of 3,67. As a result of the research, it was determined that drought stress caused negative effects ranging from 2% to 80% on all morphological traits examined (plant height, plant fresh weight, plant dry weight, stem thickness, leaf blade length, leaf width, and leaf number). At the K4 level, on average, compared to control plants, in terms of all morphological parameters, decreases were realized as 44,29% in 23-SCH-03, 41,16% in 23-SCH-07, 43,74% in 23- SCH-08, 43,36% in 23-SCH-12, and 40,89% in 23-SCH-23. In parallel with increasing stress conditions, decreases were recorded in chlorophyll contents determined by SPAD measurements. The decrease in SPAD values ranged from 2% to 36%; the most significant decrease was observed in the K4 treatment, which represents the highest stress level. Variety-based evaluations revealed that in the K4 treatment, the lowest SPAD loss compared to control plants was 20,62% in the 23- SCH-07 variety, while the highest loss was 36,24% in the 23-SCH-03 variety. YOSI values were also reduced by 8% to 69%, and this decrease varied among varieties. Specifically, at the K4 level, the lowest decrease compared to control plants was 24,18% in the 23-SCH-07 variety, while the highest decrease was 69,24% in the 23-SCH-03 variety. The study revealed that varieties experienced varying losses in plant growth parameters because of drought stress, and it was concluded that the 23-SCH-23 sweet corn variety had a higher tolerance level than other varieties.