The beneficial effects of yeast and zinc sulphate on yield and fruit quality of Navel orange trees.

Abstract

Yield and fruit quality of Navel orange trees in response to spraying yeast extract at (0.2 and 4.0%) or zinc sulphate at (0.5 and 1.0%) either singly or in combinations were evaluated during two successive seasons, 2008 and 2009 at EL Qalubia Governorate, Egypt. Tested trees were sprayed two times yearly at the beginning of March and after fruit set. Results showed that single or combined application of either yield or zinc were very effective in stimulating yield as well as physical and chemical characters of fruits rather than control. Spraying trees with 4.0% yeast extract combined with 1.0% zinc sulphate was more effective in improving total yield and fruit numbers beside increasing fruit weight, length and volume. Also, recorded the highest values of fruit quality resembled by increasing total soluble solids, ascorbic acid and decreasing fruit acidity. The best results with regard to yield and fruit quality were significantly obtained due to spraying Navel orange trees with combination of (0.4% yeast + 1.0 % zinc) followed in descending order by (0.4% yeast + 0.5% zinc) and (0.2% yeast + 1.0% zinc). 6 cytokinin as natural plant hormone. In addition, ZnSO at 1.0%. application of active dry yeast was very effective in Yeast at 0.2%. releasing carbon dioxide and stimulating photosynthesis Yeast at 0.4%. (1). Hegab (2) reported that spraying micronutrients Combinations of ZnSO at 0.5% + yeast at 0.2%. slightly reduced juice acidity of Navel orange trees. In Combinations of ZnSO at 1.0% + yeast at 0.2%. addition, Sayed (3) and Badawy (4) found that Combinations of ZnSO at 0.5% + yeast at 0.4%. micronutrient treatments gave a little effect on fruit quality Combinations of ZnSO at 1.0% + yeast at 0.4%. of Balady mandarin trees. The present study aimed mainly to evaluate the All treatments were sprayed two times yearly at the effect of sprays active dry yeast and zinc sulphate as beginning of March and after fruit set. Trees were foliar either alone or in combinations on yield and fruit separated from each side with plastic sheets to avoid quality (physical and chemical properties) of Navel orange any contamination between them, all treatments received trees.