Effect of phosphorus fertilizer and some agronomic traits relationships of two grain corn hybrids (Zea mays L.) under drought tension conditions

In order to determine the relationship between yield and some of the agronomic traits and evaluate the effect of different levels of phosphorus fertilizer on studied traits of two hybrids of grain corn under drought tension conditions, a split- split plot experiment was conducted in a randomized complete blocks design with three replications. Drought tension was applied as the main factor in three levels including: full irrigation, tension at panicle emergence stage and tension at seed filling stage. Phosphorous fertilizer as sub-factor in three levels 0, 200 and 300 kilogram per hectare (control without fertilizer, 100 percent of fertilizer recommendation and 50 percent more than fertilizer recommendation, respectively) and hybrid as the sub-sub factor at two levels (SC704 and SC700) were considered. The effect of irrigation, fertilizer and hybrid on yield and many other traits was significant. The highest grain yield was obtained under full irrigation conditions and the lowest on tension conditions at seed filling stage. There was no significant difference between 700 and 704 hybrids at different levels of irrigation. The highest dry weight was obtained under full irrigation conditions. In this situation, there was no significant differences between using 200 and 300 kilogram per hectare phosphorus fertilizer and Single Cross SC700 as well as using 100 and 300 kilogram per hectare phosphorus fertilizer and Single Cross SC700. Both in normal irrigation and tension conditions, the highest correlation was observed between grain yield and harvest index. Based on stepwise regression and path analysis, both under normal irrigation and tension conditions, the traits of harvest index and dry weight had the most effect on grain yield and in selective programs can be effective for increasing production capacity. The highest dry weight was obtained from full irrigation treatments, consumption of 200 and 300 kilogram per hectare phosphorus fertilizer and hybrid SC700, as well as full irrigation, consumption 100 and 300 kilogram per hectare phosphorus fertilizer and hybrid SC704.