The effects of deficit irrigation on yield and quality characteristics of different melon (Cucumis melo L.) varieties

In this sudy, it is aimed to evaluate the performans of three different melon types (Westeros, Burak, and Ünlü) in terms of their yield and quality parameters under fully-watered and limited water conditions. Furthermore, other purposes of the study were creating adequate irrigation programs in melon cultivation and saving irrigation water without causing a significant decrease in yield and quality. Research was carried out under field conditions for two years between 2018 and 2019 at Aksu campus.of Batı Akdeniz Agricultural Research Institute,which is located 20 km east of Antalya, on Antalya-Alanya highway. Three different melon types, namely Westeros, Burak and Ünlü, were used as plant materials. Irrigations in the study were planned according to four different irrigation levels (100%, 80%, 60% and 40%). At %100 full irrigation water level (I100), irrigation was performed when 30-40% of available water holding capacity was consumed in a 90 cm soil depth for bringing the measured soil moisture content to the field capacity. %80 (I80), %60 (I60) and, %40 (I40) amount of water treated to %100 irrigation level were used as water-deficit treatments. Soil water content was monitored by gravimetric method. Drip irrigation system was used as irrigation method in the study. The subjects discussed consisted of a combination of 4x3 factors, in total 12 subjects, including 4 irrigation levels and three melon types. Each subject was applied in the field according to the factorial experiment design in random blocks with three replications. In the firsy year of study (2018), applied amount of irrigation water ranged between 75.1 and 144.9 mm by melon types and irrigation levels. In the second year, implemented amount of irrigation water varied between 91.3 and 204.5 mm. The plant water consumption (ET) values obtained in the study varied between 214 and 301 mm. Average fruit weight showed differences between 3251 and 4466 g. In the measurements made in 2018, it was determined that the leaf water potential (YSP) values of melon types ranged between -0.3 and -1.6 bar. In the measurements made in 2019, the YSP values of melon species differed from 0.3 to -1.3 bar. Stomatal conductance values measured in the study varied between 189 mmol m-2s-1 and 681 mmol m-2s-1. The highest yield values of the melon varieties were realized at 100% irrigation levels. The highest yields determined for Westeros, Ünlü, and Burak species were 4511, 4175 and, 3980 kg da-1, respectively. The highest brix ratio in fruit was 8.9, while the lowest ratio was 5.2. When the irrigation levels and brix averages were compared, the lowest brix rate was found at 100% irrigation level. According to the results obtained from this study, the amount of seasonal irrigation water given in Kırkağaç-type melon growing in the open field in Antalya region and irrigated with drip irrigation system, varies between 145 and 205 mm under water-deficit not applied conditions. In Antalya conditions, there is no significant decrease in the yield of melon under 20% (I80 subject) water-deficit applications. Unlike, brix values and irrigation water usage efficiency values increased statistically at I40 and I60 subjects compared to I100 treatment. However, yield decreases will occur substantially under %40 and %60 water-deficit applications. Thus, it can be suggested that ideal irrigation water amount will be reduced by %20 wehere water resources is limited in melon cultivation in Antalya conditions.