The decrease of salinity effect of irrigated water by foliar application of K2SO4 in cotton (Gossypium hirsutum L.)

saline water in ground, agronomists have to use of this salt water. Foliar application of nutrients such as potassium can have quick access to the nutrients in the plant and reduce the effects of salinity assist. In order to better agronomic management for achieve to higher yield, identify of varieties with high yield potential in these conditions can assist researchers to achieve high yield. Using mutant varieties as tolerant plants to salinity can be one of the solutions. Hence this study was performed to evaluate the effect of salinity of irrigated water and foliar application of potassium sulfate on some physiological characteristics, yield of two mutant cottons. The experiment was laid out using of split factorial arrangement based on complete block design with four replications in Isfahan Agricultural and Natural Resources Center, Rudasht, Isfahan, Iran during 2014-2015. In this study, experimental treatments were three irrigation water [4 (as control), 8 and 12 dS m-1] at main plots and three cotton genotypes (LM1673, LM1303 and Shayan) with four levels of K2SO4 such as 0 (as control), 2, 4 and 6 kg in 1000l/ha in sub plots. In this experiment studied traits were fiber percent, lint yield, and physiological traits such as RWC, RWL, membrane stability index and chlorophyll content. Lint yield significantly affected by irrigation with saline water, foliar application of potassium sulfate and genotype, but the interaction between experimental factors on lint yield was not statistically significant. The results showed no significant decrease in yield with increasing of salinity levels of irrigation water from 4 to 8 dS.m-1, while when using 12 dS.m-1 saline water for irrigation, lint cotton yield reduced as 48.5% compared to control (4 dS.m-1) and fell from 4174 to 2149 kg per ha. Foliar application of potassium sulfate treatment at rate of 4 kg per hectare had the highest yield was 4425 kg per hectare compared to the control (2462 kg) was 55% increasing of yield, but had not significant differences with 2 and 6 kg per hectare sulfate potassium treatments. Between genotypes, LM-1303 genotype had the highest lint yield in rate of 3721 kg per hectares that had significant differences with Shayan genotype (3165 kg per hectares). Highest RWC in first sampling at all foliar application of potassium sulfate treatments was obtained in 8 dS.m-1 treatment at rate of 80% and in this saline treatment were not significant differences between foliar treatments. Chlorophyll content was 59 in control treatment and increasing of salinity treatment decreased it and was 54 in 12 dS.m-1 treatments. The results of the present study showed that in saline water treatments, LM-1303 mutant had the highest fiber percent and lint yield that in results can proposed this genotype for achieve to high yield in saline condition. Also, for achieve to higher yield and reducing of salinity effects can apply 4 kg per hectares potassium sulfate by spraying.