Enhancing Quality and Yield of Potato Cultivars by Bacillus subtilis and Rhizobium spp.: A Microbial Approach

The present study assessed the use of two factors. The first factor was microorganisms (10 ml L⁻¹ Rhizobium, 20ml L-1 Rhizobium, 10ml L-1 Bacillus subtilis , 20 ml L-1 Bacillus subtilis and a control treatment of 0 ml L-1 ) as Bio fertilizers to encourage the growth of many potato cultivars as the second factor, including (Bintji, Royal Kidney, Dessert, and Alfa), which were planted in the spring season (2023) in a private field in Najaf governorate . The diluted bacterial suspensions in different concentrations are added to the soil during the cultivation of potato tubers. All the plants of potato cultivars treated with the bacterial suspensions showed significant results in the measured parameters including the average length of the vegetative stem, highest number of the main aerial stem, leaf area, P%, Mg%, K% and the yield, (71.27 cm, 4.32, 16.33 cm2, 0.57%, 1.1%,1.979% and 0.93 Kg), respectively in comparison to the non-treated plants (control). Alfa and Bintji cultivars treated with a Bacillus subtilis demonstrated the most significant results among the potato cultivars in terms of stem length. The highest leaf area (26.50 cm2) and percentage of magnesium (1.40%) were achieved in the Bintji cultivar treated with the higher concentration of Rhizobium spp. The Royal Kidney cultivar treated with Bacillus subtilis showed the highest content of phosphorus, with 0.69%. In comparison the plant leaves of the Dessert cultivar contained the highest percentage of potassium (2.55%) after being treating with Bacillus subtilis. In conclusion, the addition of Bacillus subtilis was more significant and effective on different potato cultivars at concentrations of, (10 and 20 ml L-1) in comparison with the addition of Rhizobium spp.