EFFECT OF TWO GENUS OF MICROORGANISMS AS BIO-FERTILIZERS AND PHOSPHATE FERTILIZATION WITH BRASSINOLIDE SPRAYING ON PLANT GROWTH, AND QUALITY AND YIELD OF POTATO TUBERS

Abstract

The experiment was carried out in southwest Baghdad- the Radwaniyah region  during  fall season 2021 and spring season 2022 that aimed to study the effect of biological inoculation, and phosphate fertilization and spraying with Brassinolide on the growth, productivity and quality of industrial potato (Arsenal cultivar), the experiment carried out as a three factors (4×3×3) in the order of split plot within the design of Randomized complete block design (RCBD), the biological factor was distributed into main plots and interaction between phosphorus levels and the growth regulator Brassinolide within sub plots using three replicates, Bio-fertilizers included Aspergillus niger alone and Bacillus megaterium alone and the combination between them in addition to the comparison treatment, phosphorus at three levels (0, 10,200) kg P₂O₅ ha^-1 and Brassinolide spraying of three levels (0,0.1,0.2) mg L^-1. The results showed that triple combination of Bio-fertilizers together with the addition of phosphorus at the level of 200 kg P₂O₅ ha^-1 and spraying with Brassinolide at a concentration of 0.1 mg L^-1 produced significant highest leaves area (141.110 and 142.856) dm^-2 plant^-1 and dry weight of plant (58.778 and 75.000) g plant^-1 and marketable yield (32.136 and 35.606) tons ha^-1 for both seasons, the combination treatment of Bio-fertilizers together with phosphorus at the level of 200 kg P₂O₅ ha^-1 and spraying with Brassinolide at 0.2 mg L^-1 in the percentage of total sugars (3.667 and 2.453)% and the specific density (1.089 and 1.084) g cm^-2 compared to the comparison treatment produced lowest value for both seasons.