Effect of 1-MCP, NAA and IBA on fruit retention of gherkin (Cucumis sativus 'Anguria') under greenhouse conditions.

摘要

Gherkin (Cucumis sativus 'Anguria') experiences a heavy pre-mature fruit drop, resulting in low crop productivity under humid tropical greenhouse conditions. Therefore, the influence of exogenous auxines (NAA and IBA) and an ethylene inhibitor, 1-methylcyclopropane (1-MCP) on the fruit retention of gherkins was examined in a two-step glass house experiment. In the first step, foliar application of 1-MCP (50 mg L-1 at three week intervals) and NAA (10 mg L-1 at one, two and three week intervals) were carried out as separate treatments with a control (water spray), commencing at 50% flowering. In the second step, 1-MCP treatment was replaced with IBA (10 mg L-1) while two concentrations of NAA (5 and 10 mg L-1) were applied in two week intervals. Number of fruits dropped and harvested fruits per plant were monitored continuously. Results revealed that 1-MCP significantly reduced cumulative pre-mature fruit drop up to 27% (32 fruits/plant) compared to 43% in the control (50 fruits/plant). Exogenous NAA did not show a significant treatment effect. However, hormonal regulation could not improve the overall fruit yield of gherkins. In the second step, foliar application of IBA resulted the highest fruit yield (652 g/plant) due to more fruit retention. The experiment revealed the positive impact of foliar application of 1-MCP as well as IBA for retaining more fruits in greenhouse grown gherkins.