EFFECT OF SOME PHOSPHORUS COMPOUNDS AS SEED-SOAKING MATERIALS ON WINTER SQUASH (Cucurbita pepo L. ) PLANTS

Two field experiments were conducted to study the effect of squash seed soaked as a pre-sowing treatment with 1000 or 1500 ppm of Monoamonium Phosphate (MAP), Diamonium phosphate (DAP),Urea phosphate (U-P) and phosphoric acid (H3PO5) as phosphorous forms on vegetative and reproductive growth as well as fruit yield and quality were evaluated during winter months. Results showed that, different phosphorus forms and levels significantly increased all vegetative and reproductive growth traits of squash compared with control. These treatments, also, altered the sex ratio to be in favour of female flowers and led to earliness of fruit production as well as total fruit yield / plant significantly was increased . The highest early and total fruit yield were existed with 1000 ppm of UP. Also, chemical composition such as minerals content, sugars, crude protein, carbohydrates and total free amino acid in leaves as well as vitamin C., total soluble solids and titratable acidity in fruits were also increased with phosphorus treatments. Therefore, the present study, was aimed to use the phosphorus treatment not only to increase earliness and total squash fruit yield but also to avoid all cautions about the inserting of green house production in the agricultural system.