Effects of surface irrigation patterns and zinc sulfate application on physiological indices of sweet corn hybrids

Corn (Zea mays L.) is the world’s third most important cereal after wheat and rice grown primarily for grain and secondarily for fodder (Nelson, 2005).Sweet corn is used as a fresh or processed vegetable.Sweet corn contains higher kernel protein, oil,starch, sugar contents and many other nutrients than the other maize types(Abolhasani et al., 2004). Sweet corn is favorable for fresh consumption because of its delicious taste,delicate crust and soft and sugary texture compared to other corn varieties. The human body needs nutritious food to stay healthy(Baybordi, 2006 ;Soriano et al., 2004). Drought is one of the factors,which threatens the agricultural products in most parts of the world . Shortage of water, on the other hand, is an important limiting factor in crop production.
This test was conducted in agricultural year of 2015 in factoriel split plot style in completely randomized block design in three replicates in the Azad University research field of Arak (34°40′ N 58°25′ E and height of 1150 m). The soil of experimental plot was loam, pH 7.70,EC 1.20 dSm-1, organic carbon 1.50%,available nitrogen 0.02%, phosphorus 0.6% and potassium 0.2%.Experiment treatments including irrigiation patterns were carried out at three levels of conventional furrow irrigation (I1), fixed every other furrow irrigation (I2) and alternate every other furrow irrigation (I3). Subplots were considered with three levels of without zinc spray(control)(zn1), drop zinc spray(2/(1000 ) lit/ha )(zn2)and fast zinc spray(2/(1000 ) lit/ha ) (zn3)and Chase(v1) and Challenger (v2) as sweetcorn varieties.
The ANOVA results showed that the effect of irrigation pattern at 1% level and the effects of foliar application of zinc and the effects of different genotypes and their interactive effects on Chlorophyll a were significant at 1% probability level. The comparison of varieties showed that Challenger had the highest chlorophyll a (0.889 gr.grfw)compared to chase hybrid(0.779 gr.grfw) during full irrigation,alternative and furrow irrigiation condition by 14.37% .In examining the interactive effect of treatments it was observed that the maximum Chlorophyll a belonged to I1ZN3V2 treatment (control irrigation, fast zinc and Challenger hybrid) by 0.995 gr.grfw and the lowest belonged to I2Zn2V1 treatment (furrow irrigation, Drop zinc and Chase hybrid) by 0.598 gr.grfw that were significantly different at 1% level.
Foliar application of zing has a significant effect on yield and yield components and physiological parameters of corn, so that we witnessed 11.65% of the increase of grain yield in fast zinc treatment than the control treatment without foliar application of zinc which could result from the stimulation of grain metabolism and consequently the prevention of damage to proteins, chlorophyll, nucleic acids and enzymes which cause the growth of plant chlorophyll and its higher storage in grains. According to the results of the research, in case of water restriction, the alternate irrigation pattern can be applied because the decrease of yield in such conditions was insignificant in comparison to the normal irrigation particularly in Challenger hybrid. Moreover, the foliar application of zinc, particularly zinc sulfate with fast zinc composition leads to the stable yield in stress conditions which can be proposed to the farmers in Markazi Province and Arak.