Response of Some Rice Cultivars to Rhizobacteria (PGPR), Different Rates of Nitrogen Fertilizer and its Combinations under Flooding Condition

To evaluate the role of growth promoting Rhizobacteria (PGPR) either added a single or combined with nitrogen fertilizer (urea) on yield and yield components of five Egyptian rice cultivars.i.e. Giza179, Sakha102, Sakha105, Sakha106 and Sakha103.Two field experiments were carried out at the farm of Sakha Agriculture Station during 2014 and 2015 growing seasons. Five fertilizer were application different combination between Rhizobacteria and nitrogen fertilizer; Recommended dose of N 165 Kg N/ha (T₁), Rhizo+1/4 recommended dose of nitrogen (T₂), Rhizobia only (T₃), Rhizo+1/2 recommended dose of nitrogen(T₄) and Rhizo+3/4 recommended dose of nitrogen(T₅).The Experiments were conducted using the Randomized Complete Block Design (RCBD) with splitplot arrangements. Split plot design was used with four replication. The main plots received the five rice cultivars while the fertilizer treatments were located in sub plots. The recorded data were chlorophyll content of flag leaf, plant height (cm) at harvest, number of tillers (m^-2), number of panicles (m^-2), panicle length (cm), panicle weight (g), number of filled grains/panicle, number of unfilled grains/panicle, 1000- grain weight (g), grain and straw yield (t/ha). Results indicated that the application of either Rhizo+3/4 dose of N (T₅) or recommended dose of N (urea) (T₁) gave nearly the highest value of growth characters, yield and yield components. While, Rhizobia application alone gave the lowest value of the previous studied characters. The results also clarified that the treatments of combined Rhizobacteria with 3/4 of recommended dose of urea produced nearly the same grain yield as recommended dose with very little difference between the tested cultivars. According to the results, it can save 1/4 of the recommended dose of nitrogen fertilizer (165 kg N/ha)without significant reduction in the yield beside minimized the economical and the pollution resulted from chemical fertilizers.