The effect of drought stress on the yield stability and grain field elements of aerobic rice genotype in the north of khouzestan

Increased drought to maintain the water potential in plant causes a reduction in grain yield (Majd et al., 2009). The severe decrease in the available water for the multi-days irrigation regimes lead to the negative impacts on the plant and will reduce vegetative growth, particularly in seedling stage (Salehifar et al., 2014). The supplemental irrigation can present a manageable alternative to reduce the negative aspects of the terminal drought (end of season) at the reproductive stage (Nehbandani et al., 2016). The current research is aimed to study impacts of different irrigation regimes on growth steps of indices of grain yield of aerobic rice genotypes in order to identify physiological response to resistance mechanism or to be sensitive to low water and waterlogging by studying changes in the mentioned traits and positive role that is played t increase grain yield as well as to provide functional traits to breed rice genotypes.
An experiment was carried out to study of irrigation regimes on rice genotypes grain yield of The north of Khuzestan province in a split-plot arrangement using randomized complete block design with three replication in 2014 and 2015 cropping seasons at Shavoor Agricultural Research Station, Dependent in Research Center of Agricultural and Natural Resources of Khuzestan. For exposing rice genotypes to Four different irrigation regimes (3 and 7 days), and 12 genotypes were randomized in sub-plots.
The purpose of present research to study the effect of irrigation round reduction as a drought tension on grain field traits, the present of full and completely full grains, 1000-kernel weight and at last their output involving the percent of full grains in tension conditions, the index of tolerance to tension of recent traits, the percent of full grains in desirable conditions, the percent of full grains in tension conditions, 1000-kernel weight in tension conditions, the index of sensitivity to grain weight drought, grain yield in desirable conditions, grain yield in tension conditions, the index of tolerance to tension of recent trait, the index of drought loss, SSI, tolerance index, the index of drought tension tolerance, the amount of tolerance yield reduction with irrigation and genotype as split-plot as random blocks. In terms of grain yield except stable genotype of vendana having the highest index of tolerance to drought of yield, we observed reduction of grain yield in other genotypes.
The findings of this experiment showed that the genotypes had the lowest resistance to the drought had the most sensitive indicator to the drought as well as the lowest tolerance index to the drought which ultimately leads to reduce the yield of the genotypes, but the genotypes that were more resistant to the drought had the highest tolerance to the drought stress. They could adapt themselves to the stressful situations and keep or increase their grain yield. In this regard, the Vandana aerobic genotypes not only did not decline in its yield under the drought stress, but also had the increase of 390.6 kg per hectare, which can be very suitable for planting in the drought conditions. It can be used the best indices of the Vandana genotypes in the short or long-term program to modify the production of the varieties with a greater compatibility.