The effect of foliar spray with algae extract and/or potassium nitrate on the quantity and quality of Barhee date palm yields was investigated during the 2017 and 2018 seasons. Inflorescences of Barhee date palms were sprayed twice, after pollination (1st April of each season) and one month later, with algae extract at concentrations of 0.5% and 1.0% and with potassium nitrate at concentrations of 1% and 2% applied individually or in combinations. The obtained results showed that all of the sprayed treatments enhanced the yield and fruit properties when compared to the controls. Spraying inflorescences of Barhee date palms with algae extract and/or potassium nitrate had a significant effect on the yield and on the physical and chemical properties of the fruit when compared with the untreated palms. The increase in yield and qualitative properties was associated with increasing concentrations of both materials (algae extract and potassium nitrate). The best results were detected with spray containing high rates of combined treatment (1% algae extract + 2% potassium nitrate) applied twice in both seasons studied because this treatment resulted in the highest value of fruit and bunch weight, increased the yield per palm compared to the control by about 60.2%, and improved the fruit physical properties (fruit length, fruit diameter, fruit shape index, flesh weight, and seed weight) and fruit chemical properties (total soluble solids (TSS); acidity; TSS/acid ratio; tannins; and reducing, nonreducing, and total sugars) of the Barhee date palm given the experimental conditions.

The present work aimed to evaluate green-nano manganese produced at the Microbial Biotechnology Department, National Research Centre, Egypt, and assess its impact on the growth, yield, and fruit properties of grapevines. To this end, two experiments were conducted. The first was microbiological, where several incorporation strategies were utilized to enrich the yeast with manganese, as follows: (1) manganese was added to the liquid medium (non-growth phase), and (2) manganese was added after 24 h of incubation (growth phase). The results showed that the non-growth phase had a reduced possibility of medium contamination. The manganese concentration in the yeast cells was increased due to manganese sulfate in the medium. The manganese incorporation in yeast cells was 99.93% (1.205 × 105) higher than that of the medium at 0.0195 g/L of manganese. Although the concentration of manganese in the medium raised the optical density (OD) of the yeast cell biomass, manganese sulfate had no passive influence on it. The second experiment was horticultural, where Flame Seedless grapevines were sprayed with frozen and active fresh yeast enriched with manganese that resulted from the microbiological experiment. Grapevines were sprayed twice a year at 10 or 20 cm³/L, and the results were compared with those for the mineral and chelate forms. The results demonstrated that yeast extracts in both forms showed positive effects on grapevine. The most effective treatment with regard to growth, yield, and fruit properties was frozen yeast enriched with manganese at 20 cm³/L, which yielded 10.14 and 12.6 kg/vine, compared with the control, which recorded 3.7 and 5.6 kg/vine in the two seasons, respectively.

Two experiments were conducted to develop a Nano green manganese and assess its effect on grapevines. The first experiment was microbiological, where several incorporation strategies were utilized to enrich the yeast with manganese, as follows: (1) adding manganese to the liquid medium (growth phase), (2) adding after 24 h of incubation (non-growth phase). As the results, growth phase reduced the possibility of medium contamination. Manganese concentration in the yeast cells was increased as that of manganese sulphate in the medium. Manganese incorporation in yeast cells was 99.93% higher than that of the medium at 0.0195 g/l of manganese. Although the concentration of manganese in the medium raised the OD of yeast cell biomass, manganese sulphate had no passive influence on it. The second experiment was horticultural, done on Flame Seedless grapevines, since both active fresh and frozen yeast enriched with manganese resulted from the first experiment were sprayed twice a year at 10 or 20 cm3/l comparing with manganese sulphate, and manganese chelate. The results demonstrated that yeast extracts in both forms increased the yield and improved fruit properties. The most effective treatment on vegetative growth, yield and fruit properties was the frozen yeast enriched with manganese at 20 cm3/l.