Effect of methanol and seed inoculation with plant growth-promoting rhizobacteria on grain filling components, chlorophyll content and yield of safflower under various irrigation levels

In order to study the effect of methanol and seed inoculation with plant growth promoting  rhizobacteria on grain filling components, chlorophyll content and grain yield of safflower (Carthamus tinctorius L.) under various irrigation levels, a factorial experiment has been conducted based on randomized complete block design with three replications at the research farm of University of Mohaghegh Ardabili in 2020. The experimental factors include irrigation (full irrigation as control, irrigation withholding at 50% heading-bud, and flowering stages), biofertilizers application (no application as control, seed inoculation with Flavobacterium, Pseudomonas and both application of Flavobacterium and Pseudomonas), and methanol foliar application: (foliar application with water as control and foliar application with 10% and 20% volume of methanol). The results show that the content chlorophyll a (41.57%), b (74.59%) and total chlorophyll (49.33%), grain filling period, and effective grain filling period (27.32% and 72.89% respectively) and grain yield (69.2%) have increased under full irrigation condition, foliar application 20% volume of methanol, and both application of Flavobacterium with Pseudomonas in comparison with irrigation withholding at 50% heading-bud and no application of biofertilizers and methanol. Generally, the results show that application of plant growth-promoting bacteria and methanol can increase grain yield of safflower by improving chlorophyll content and grain filling components under water limitation condition.