EXAMINATION OF AGRO-PHYSIOLOGICAL TRAITS OF DIFFERENT CULTIVARS OF MAIZE (Zea mays) WITH LEAF AND EAR TOPPING

Abstract

The current research aimed to examine the agro-physiological traits of different maize cultivars, with and without topping, in the two crop years of 2017-18 and 2018-19, for which a factorial randomized complete block design (RDBC) in three replications was devised. The research treatments included experimental groups of control samples, samples with topping of half of the ear after pollination, samples with topping of the two upper and lower leaves of the ear after pollination as the first factor, combined with seven maize cultivars of SC704, Consor, Cordona, Karaj 703, Kusha, Fajr and Daniyal 690 as the second factor. In the first and second years after preparing the substrate, the seeds of different cultivars were planted in the plots based on the research treatments. Topping operations were performed after pollination for all samples. The results showed that the highest value of stem height (168.6 cm) was obtained in the control treatment of the Karaj 703 cultivar. The highest weight of one thousand seeds (423.6 g) was obtained in the leaf-topping treatment of Karaj 703, and the highest amount of seed yield (1126 g m2 ) was obtained in the leaf-topping treatment Consor cultivar. The highest amount of chlorophyll a (98.46 mg g fresh weight, FW), the highest amount of chlorophyll b (138.7 mg g FW), and the highest amount of carotenoid (74.33 mg g FW) were all obtained in the leaf-topping treatment of SC704 cultivar. The highest amount of catalase enzyme (58.73 mg protein min) was obtained in the control Fajr cultivar. However, the highest amount of peroxidase enzyme (173.4 mg protein min) and the highest activity of polyphenol oxidase enzyme (64.7 mg protein min) was obtained in the control treatments of the Kusha cultivar. The cultivar with optimal topping performance was proven to be the Consor cultivar.