Effect of plant growth regulators and stress conditions for accelerated peak harvest of gherkin

Abstract

Gherkin (Cucumis anguria L.) is a determinant crop with a short life cycle (75 days). The lack of enough time to harvest maximum yield due to short duration of yala off (time between yala and maha) season is a major challenge faced by Sri Lankan farmers. This study was conducted to identify the most suitable treatment to accelerate the peak harvest of gherkin under protected house conditions at the Faculty of Agriculture, University of Ruhuna. There were two pot experiments conducted, as the first experiment was in soilless media, and the second experiment was in soil media. The experiment was laid out in Completely Randomized Design (CRD) with six treatments, T1(100 ppm ethrel,0.1 ml/l at 4th leaf stage), T2(0.001 mol/l salicylic acid after first flowering), T3(2 ml/l cycocel,1 week before flowering (WBF), T4(0.625 ppm sodium nitrophenolate,1 WBF), T5(3 temporary wilting- water stress), and T6(2.5 g/l of K-44,1 WBF-K stress) with four replicates from each. Vegetative and reproductive data were recorded, and they were statistically analysed by ANOVA. Means were separated by Duncan’s multiple range test. The results revealed that, significantly lowest internodal length was recorded in T3(6.34 cm, 2.98 cm) while the highest in T2(9.03 cm, 8.25 cm) for both soil and soilless media respectively. Significantly lowest leaf area was recorded in T3(44.75 cm2,27 cm2) while the highest was in T2(136.50 cm2) and T6 (189 cm2) in soilless and soil media respectively. T2(26.80) was taken minimum number of days for first flowering in soilless media while T3(28.00) was recorded significantly lowest number of days in soil media. Significantly highest number of fruits were obtained from T2(25.25) during 7th and 8th weeks in soil media. Significantly highest fruit weight was recorded by T2(82.365 g) in 2nd week in soil media while T3(195.02 g) was recorded highest weight of fruits at 10th week in soilless media. T2 provided peak yield earlier than other treatments in both soilless (6th week) and soil media (7th and 8th). Research findings conclude that, application of T2 (salicylic acid) after first flowering at 0.001 mol/L ensures the minimum time for peak harvest of gherkin (6th -7th WAP).