Greenhouse seed production of two dwarf green bean cultivars in relation to the duration of irrigation
As good quality irrigation water becomes increasingly scarce in the Mediterranean region, especially in coastal areas where greenhouses are located, methods of economizing water consumption are essential. Therefore, the effect of the duration of irrigation on the quality and yield of seed of two cultivars of dwarf green bean ('Larma' and 'Montano', Phaseolus vulgaris L.) was studied during fall and spring in Greece. Seeds were sown on 11 Sept. 2000 (fall crop) and 23 Feb. 2001 (spring crop) in peat compost and when the plants had two expanded leaves (11 and 20 days after sowing, respectively), they were transplanted to the soil of an unheated, plastic-covered greenhouse. The following irrigation treatments were applied: 1) irrigation for the entire duration (control), 2) irrigation until the first pods were dry, 3) irrigation until approximate to50% of the pods had filled, and 4) irrigation till flowering. Fall cultivation was not suitable for seed production due to low yield and reduced seed quality. By contrast, the spring crop had a higher yield, seed size and good germination. Stopping irrigation of the spring crop at the drying of the first pods achieved an approximate to20% saving in water without significantly affecting seed yield or quality. Earlier discontinuation of irrigation to achieve greater savings of water caused a reduction in yield, but did not affect seed quality.