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Confectionary pumpkin ( Cucurbita pepo L.) is one of the important snacks preferred by consumers in Turkey due to its higher nutrient contents. However, there is no comprehensive study on water management in pumpkin cultivation in many countries including Turkey. Therefore, a 2-year study (2013–2014) was conducted to determine the effects of different irrigation intervals ( S ) and irrigation levels ( I ) on the seed yield and yield components of drip-irrigated confectionary pumpkin under the Middle Anatolian climatic conditions in Konya, Turkey. The experimental design was made in randomized blocks, in a 3 × 5 factorial scheme, with three replications. Treatments consisted of three irrigation intervals ( S 7 : 7 days, S 14 : 14 days, and S 21 : 21 days) and five irrigation levels ( I 100 : 100% irrigation or full irrigation, I 75 : 75% of full irrigation, I 50 : 50% of full irrigation, I 25 : 25% of full irrigation, and I 0 : no irrigation). Seasonal plant water consumption or actual evapotranspiration (ET a ) of irrigation treatments varied from 194.2 to 660.2 mm in 2013 and from 208.6 to 629.6 mm in 2014. The irrigation interval ( S ) and the irrigation level ( I ) significantly affected the seed yield and quality of pumpkin in both the years. Typically, no significant differences were found among S 7 I 100 , S 7 I 75 , and S 14 I 100 treatments in both the years although S 7 I 100 treatment produced the highest seed yield (1274 kg ha −1 ). In 2013, except for 1000-seed weight, interaction between the irrigation interval and the irrigation level significantly affected the seed yield, the number of fruits per plant, seed yield per fruit, and mean fruit weight; however, in 2014, the effects of S × I interaction on the seed yield and yield components were not significant. Seed yields were significantly affected in a linear relationship by the amount of irrigation water and evapotranspiration in both the years. Seasonal yield response factors ( k y ) were 0.92 and 1.27 in 2013 and 2014, respectively. In conclusion, I 100 with a 7-day irrigation interval is recommended for pumpkin grown under field conditions to maximize the yield. However, if the irrigation water is scarce, it will be suitable to irrigate pumpkin with either 25% water deficit (7-day interval) or full irrigation (14-day interval) in semiarid conditions. [ABSTRACT FROM AUTHOR]

In arid and semi-arid regions, plant responses to water deficits at different phenological stages should be investigated for efficient use of water resources and sustainable irrigation management. This study was conducted under the regional conditions in the Konya province with a semi-arid climate for two years (2016–17) to determine the effects of irrigation applied at different growth stages on yield and quality traits of melon (Cucumis melo L. cv. Dardanos). Thus, a total of eight different irrigation treatments were implemented at three different growth stages of melon (from planting to flowering (V), flowering to fruit swelling (F), and fruit swelling to harvesting (M)). These treatments were specified as single-stage irrigation (V, F, and M), two-stage irrigation (VF, VM, and FM), irrigation for the whole season (VFM–stress-free), and non-irrigated. The seasonal total water consumption varied between 129.7 and 418.5 mm in 2016 and between 161.8 and 428.6 mm in 2017. The greatest fruit yield (52.9 t/ha) was obtained from stress-free VFM treatment; however, significant decreases were observed in fruit yields for other treatments. When yield and quality traits were assessed together, principal component analysis (PCA) revealed that VF and FM treatments had similar values to VFM treatment. With regard to irrigation water productivity (IWP), there were no significant differences between VM and VFM treatments, and VM treatment provided about 47% water saving. On the other hand, significant decreases were observed in fruit yields of V, F, and M treatments, in which irrigation and the water stress were applied during only a single phenological stage and the other two periods, respectively. Since the yield response factor (ky) for the whole growing season of melon was greater than 1.0 (1.30), the melon was considered sensitive to water stress under semi-arid climatic conditions. In conclusion, two-stage irrigation treatments (VF, VM, and FM) could be applied in well-scheduled irrigation programs of melon for efficient use of water resources and sustainable irrigation management in arid and semi-arid regions. • As compared to VFM, the reduction in fruit yields varied between 29% in FM treatment and 84% in non-irrigated treatment. • With regard to the IWP, compared to VFM treatment, VM treatment provided about 47% water saving. • VF, VM, and FM treatments could be applied in irrigation programs of melon in arid and semi-arid regions. • Yield response factor (ky) was 1.30 for the whole growing season of melon. [ABSTRACT FROM AUTHOR]

Drought adversely affects crop production in areas with water shortages. In such areas, various methods need to be implemented to alleviate the effect of water stress on plants. Nitric oxide (NO) is an important plant growth regulator that affects various physiological processes. In this study, we determined ways to increase water-stress tolerance of lettuce by applying exogenous sodium nitroprusside (SNP, a donor of NO). In total, 12 treatments were administered, including three SNP doses (0, 50, and 100 µM) and four levels of irrigation (I 100 , I 80 , I 60 , and I 40). An increase in the doses of NO partially increased the water consumption of lettuce under full and deficit irrigation conditions. The highest water consumption (125.1 mm) and the highest yield (39.1 t/ha) were recorded for lettuce plants that were administered the I 10 0 treatment with 100 µM SNP. SNP significantly increased the lettuce yield and irrigation water productivity (IWP) under deficit irrigation and full irrigation. SNP promoted chlorophyll synthesis by increasing photosynthesis. The application of 100 µM SNP increased catalase (CAT) activity approximately three times compared to CAT activity in the control group, and it also significantly increased peroxidase (POD) activity. Additionally, high doses of SNP reduced membrane damage in lettuce leaves. These results indicated that under water stress, exogenous NO improves photosynthesis by increasing chlorophyll synthesis, activates antioxidant enzymes, such as CAT and POD, protects lettuce against oxidative damage, and increases irrigation water productivity, thus increasing the yield. • SNP significantly increased the lettuce yield under full and deficit irrigation conditions. • SNP increased the CAT enzyme activity by approximately three times under different irrigation regimes. • SNP increased irrigation water productivity by up to 30%. • The application of SNP can save 20% of water in lettuce cultivation in water-scarce environments. [ABSTRACT FROM AUTHOR]

• 25 % water-saving can be achieved in watermelon cultivation by using rootstock • The rootstocks and irrigation levels affected yield and quality of watermelon. • TZ148 rootstock showed superior performance in yield and yield components. • The citron watermelons can be used as rootstock candidates. Deficit irrigation practices and utilization of rootstocks that are tolerant to water stress are critical strategies for the protection of water resources and sustainable irrigation management, especially in arid and semi-arid areas. Therefore, this study was carried out to investigate the yield and quality of watermelon grafted onto different rootstocks under deficit irrigation conditions during 2017 and 2018 in the Konya Plain of Turkey, where the semi-arid climate is prevalent. In this study, five different plant materials, such as citroides1 (A 1), citroides2 (A 2), gourd (A 3), hybrid TZ148 (A 4) rootstocks grafted with the Crimson Tide variety, and non-grafted Crimson Tide as control (K 1), were used as the main-plots. Five different irrigation levels, calculated by taking into account the amounts of cumulative water (Ep) that evaporated at 7-day intervals from Class A Pan (I 100 = 1.00Ep; I 75 = 0.75Ep; I 50 = 0.50Ep; I 35 = 0.35Ep, and I 0 = rain-fed), were used as the sub-plots. When the average of experimental years was considered, the highest rate of evapotranspiration (ET) was found in the plot A 4 I 100 (615 mm). The highest fruit yield was obtained from the A 4 I 100 (93.4 t/ha), and an increase in yield of up to 35 % was achieved in the A 4 I 100 , compared to non-grafted plants applied I 100 irrigation level (K 1 I 100). The analysis of data by both separate evaluation and principal component analysis (PCA) revealed that the yield values obtained from plants grafted onto A 4 , A 1 , and A 2 rootstocks applied I 75 irrigation level were higher than non-grafted plants applied I 100 irrigation level. The water productivity (WP) and irrigation water productivity (IWP) ranged between 7.1–17.4 kg/m3 and 11.7–25.0 kg/m3, respectively, and a significant increase in the values of WP and IWP was achieved by grafting. This two-year study revealed that the performances of citron watermelon rootstocks were found close to the TZ148 rootstock in terms of fruit yield, certain yield components, WP, and IWP. Thus, it has also been demonstrated that the citron watermelons could be used commercially as watermelon rootstocks, and citron watermelon rootstocks could be used as watermelon rootstocks in breeding programs, in order to save water, especially in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]