Effect of Irrigation Regime on the Cultivation of Five Wild Colocynth[Citrullus colocynthsis (L.) Schrad.] Ecotypes in Terms of Their Growth, Seed Yield and Oil content

Abstract

The objective of this research was to evaluate the response of five wild colocynth (an important medicinal plant) ecotypes to
irrigation regime as a basic input of cultural practices. The research was laid out in a split plot design with three replications. Treatments were two irrigation regimes (Q1= 100 % Etc and Q2= 50 % Etc) and five wild colocynth ecotypes (G, SF, SD, GD and NK). The experiment was run for two seasons (2014 and 2015). Parameters measured were days to 50 % flowering, number of fruits per plant, number of seeds per fruit weight of 1000 seeds, seed yield and oil content of seeds. Days to 50 %
flowering were not significantly affected by watering regimes for the two seasons; however, ecotypes were significantly effective in the first  season only. Number of fruits per plant was not significantly affected by watering regimes in both seasons; yet, ecotypes were significantly affected in the first season only. The highest number of fruits/plant was
produced by ecotype G in the first season and by NK in the second season. The lowest number was produced by ecotype SD in both seasons. Number of seeds per fruit was not significantly different between the watering regimes in both seasons; it was, however, significantly different among ecotypes in both seasons. There was no significant difference in seed yields between watering regimes in both seasons. Ecotype GD produced the highest seed yield in both seasons.
The two watering regimes and ecotypes were significantly different regarding weight of 1000 seeds in the first but not in the second season.
Mean oil percent of seeds resulting from irrigated ecotypes (15.2%) was higher than that of seeds collected from the wild (12.1%).
Moreover, mean oil percent from seeds produced by high and low irrigation was individually higher than that of seeds from the wild habitat. In the wild habitat, SD produced the highest (16.0%) oil percent and NK the lowest (6.4%). When irrigated, ecotypes showed differential positive response. In conclusion, wild colocynth ectypes responded positively to irrigation regarding oil content of seeds, which is the most important product, indicating possibility of inclusion of colocynth in the existing cropping system thereby ensuring its conservation and economic use. More research, however, is needed to
determine, precisely, the irrigation water requirement for colocynth seed production.