Identification of Water Usage Efficiency for Corn (Zea mays L.) Lines Irrigated with Drip Irrigation Under Green House Conditions as Per Plant Water Stress Index Evaluations

Abstract

The present study was conducted as a greenhouse study under Çukurova conditions during the years 2011-2012. Two different dent corn lines (5A2-B and 22K) were used as the plant material of the experiments. Crop water stress index (CWSI) values determined through leaf canopy temperature measurements performed ahead of irrigations were used to find out water use efficiencies. Experiments were conducted in randomized blocks-split plots experimental design with three replications. Drip irrigation was used for irrigations and two different irrigation programs were created as of I100 (supplying 100% of depleted water in every seven days) and I75 (applying 75% of depleted water. The amount of irrigation water applied for in the interaction of I100 irrigation and corn lines (5A2-B and 22K) in the first and second year were respectively varied between 253.0-274.0 and between 238.0-261.0 mm, seasonal plant water consumptions varied between 294.0-305.0 and between 284.6-302.6 mm, kernel yields varied between 2950.0-2990.0 and between 3130.0-3186.0 kg ha-1 . With regard to (in the interaction irrigation treatments x corn lines), the lowest and the highest CWSI values were observed in the interaction full irrigation (I100) and of the line 22K as 0.22 and in deficit irrigation treatment (I75) of the line 5A2-B as 0.41 in the first year; in full irrigation treatment (I100) of the line 22K as 0.20 and in deficit irrigation treatment (I75) of the line 5A2-B as 0.36. The greatest and the lowest chlorophyll contents (in the interaction irrigation treatments x corn lines) were respectively observed in I100 treatment of the line 22K as 58.3 spad and in I75 treatment of the line 5A2-B as 50.9 spad in the first year; in I100 treatment of the line 22K as 59.1 SPAD and in I75 treatment of the line 5A2-B as 55.1 spad. While the effects of irrigation treatments on average dry matter contents of the lines were not found to be significant, significant differences were observed in water use efficiency and kernel yield of dent corn lines (p<0.01). Current findings revealed that 22K dent corn line was prominent with regard to CWSI and chlorophyll content and the relevant line was also able to use available water holding capacity with an optimum efficiency. Therefore, it was concluded that the dent corn line (22K) could be used in further researches to improve water efficiencies.