INCREASING ORGANIC PRODUCTION OF SUMMER SQUASH BY MODULATING PLANT SEX RATIO

Two year experiments were carried out in open field, to study the effect of complete replacement of mineral nitrogen fertilization by organic nitrogen source (chicken manure), combined with using garlic extract as seed soaking and/or spraying seedling by ethrel, on the vegetative growth parameters, earliness, sex ratio, number of fruit/plant, total production and fruit quality, of four squash cultivars: ‘Eskandrany’ and the hybrids ‘Services plus’, ‘Rivera’ and ‘Mabroka’. The experi-ments occurred during summer growing seasons (June-August) in newly reclaimed sandy soil, aiming to overcome the negative impact of long day, high temperature and low availability of nitrogen in the soil and the productivity of the cultivars under the above environmental conditions, gathering with complete organic fertilization. Sixteen treatments resulted from the combination of seeds soaking in garlic extract and/or spraying seedling by ethrel and non treated (control), on the four squash cultivars. Results strongly showed that, complete replacement of mineral nitrogen fertilization by chicken manure combined with control treatment were associated with early flowering and lower fruit production. Whereas, soaking squash seeds in garlic extract and/or spraying squash seedling with ethrel, stimulate plant growth, increased female flowers ratio, fruit production and quality. In conclusion the best results were obtained when squash seeds were soaked in garlic extract before sowing and then the seedlings sprayed at 1-2 true leaves stage with ethrel.