Comparison of different nutritional levels and the effect of plant growth promoting rhizobacteria (PGPR) on the grain yield and quality of sunflower

An experiment was conducted in 2007 and 2008 to study the effect of organic, chemical and integrated nutritional levels and Plant Growth Promoting Rhizobacteria (PGPR) on the grain yield and quality traits of sunflower (Helianthus annuus L.). A total of five nutritional levels, including 100% organic (F1), 25% chemical and 75% organic (F2), 50% chemical and 50% organic (F3), 75% chemical and 25% organic (F4) and 100% chemical (F5), were utilised in the main plot, and two levels of PGPR inoculation (I0, I1) were established in sub-plots, respectively. The treatments were arranged in a split-plot design based on RCB with three replications. The height, leaf area index, biological yield, 1000-seed weight, number of seeds, head diameter, harvest index and qualitative properties (except for the oil content) were superior in the F3, F4, and F2 integrated nutritional levels compared to the completely organic (F1) and chemical levels (F5). In the F3 integrated level, the total increased seed yield (2924.9) was approximately 40% of the lowest seed yield for the F1 level (1777.1). According to the results for the yield, the order was F3>F4>F2>F5>F1 respectively. The highest and lowest contents of oil were observed in the F1 level (51.07) and F3 level (49.35), respectively. The results showed that inoculating the seeds with PGPR increased the qualitative and quantitative properties of sunflower significantly, as compared to the control treatment.