The effect of deficit irrigation on yield and quality of second crop sesame (Sesamum indicum L.)

This experiment was carried out in Bursa, which has a sub-humid climate, in order to examine the water-yield relationships, responses of yield and quality components under deficit irrigation of second crop sesame plant (Sesamum indicum L.) irrigated with drip irrigation method. In this experiment, 5 different irrigation treatments were selected, and the moisture level in the plant root zone was observed every 7 days and 100% (S1) of the water required to bring the existing moisture in the soil to the field capacity, 75% (S2) of the water required for S1 treatment, 50% (S3) of the required water for S1 treatment, 25% (S4) of the water required for S1 treatment and the rainfed treatment (S5) were programmed. The experiment was applied in 3 replicates according to the randomized blocks experimental design. In the study, the locally registered "Muganlı-57" variety was used. According to the research results; the total amounts of irrigation water applied to irrigation treatments was between 127,0-354,7 mm. Crop evapotranspiration values were 246,0-449,5 mm. Kernel yield values, plant height values, first capsule height values, side branch number values, capsule number values, grain number in capsule, thousand grain weight, protein ratio, protein yield, oil ratio and oil yield were obtained as respectively, 76,3-189,2 kg da-1, 91,0-140,8 cm, 43,7-60,9 cm, 1,2-3,6 pieces plant-1, 40,3-59,3 pieces plant-1, 47,3-61,3 pieces capsule-1, 2,97-3,87 g, 18,6-20,4%, 15,5-35,8 kg da-1, 56,3-62,6% and 43,0-109,9 kg da-1. In the study, the seasonal crop yield response factor, ky, was determined as 1,28. Water use efficiency (WUE) of the sesame plant was found between 0.31-0.43 kg m-3. Irrigation water usage efficiency (IWUE) was found between 0,50-0,57 kg m-3. As a result, S1 irrigation treatment can be suggested as irrigation program in order to reach the highest grain yield (189,2 kg da-1) in the second crop sesame plant. If the water resources in the region are limited, taking into account the WUE and IWUE values, the S2 treatment (25% water deficit) can be preferred as an irrigation program in terms of water savings. However, under this condition, it can be said that there may be a significant decrease of approximately 10,7% in the grain yield and the deficit irrigation management should be planned very carefully.