Morpho-physiological effects of environmental stress on yield and quality of sweet corn varieties (Zea mays L.)

Sweet corn is cultivated in different climatic regions of the world, and consumed either fresh or processed. Morpho-physiological effects of environmental stress on yield, yield components and quality of some sweet corn varieties were investigated in field experiments conducted at Southeastern Anatolia Region of Turkey during 2019 and 2020 growing seasons. The experimental lay out was randomized blocks with three replicates. Eight candidates and two control sweet corn varieties classified as moderate maturity (FAO 650-700) were used in field experiment. Mean values of pollen fertility rate (PFR, %), total soluble solids (TSS, degrees Brix), abscisic acid (ABA, nmol/g DW), ear length (EL, cm), plant height (PH, cm), number of grains per cob (CGN, grain) and fresh cob yield (FCY, t ha(-1)) were significantly different between years and sweet corn varieties. The PFR, TSS, ABA, EL, PH, CGN and FCY ranged from 40.29-67.65%, 13.24-20.09 degrees brix, 7.74-21.04 nmol/g DW, 9.69-15.98 cm, 97.80-171.34 cm, 289.15-420.33 grain and 4.15-10.23 t ha(-1) respectively. The FCY, yield components and PFR values in the second year that had a higher temperature and lower relative humidity were lower compared to the first year, while ABA and TSS values were higher in the second year. Statistically significant correlations were recorded between the parameters investigated except FCY and TSS. The FCY and other parameters of sweet corn varieties, which produced high ABA phytohormone, were high, and the ABA hormone significantly contributed to plant growth under stress conditions. The results revealed that the PFR physiological parameter and ABA hormone in the plants provide important information about stress level and stress tolerance level of the cultivars, respectively. Despite adverse environmental stress conditions, the FCY of SADA-18.7 variety, one of the candidate varieties, was higher than that of the control and the mean value of the experiment.