Changes in morpho-physiological traits of rice cultivars upon different fertilization regimes

Abstract

Improving crop yield is one of the main challenges in lands with intensive agriculture. In order to study the nutritional treatment effects (macro and micro elements) on agronomic and morpho-physiologic traits on three different rice cultivars, a field experiment was conducted at Mazandaran province of Iran as a factorial arrangement based on a randomized complete block design with three replications. Three different fertilizer treatments including complete (NPK + micro elements), macro (NPK) and micro (N + Mn + Fe + Zn), along with a control (nutrient free) were applied. The results showed that distinctive cultivar’s 1000-grain weight and biomass, unlike other traits, was not significantly affected amongst the treatments. Fertilizer treatments, however, had significant effect on the studied agro-morphological, biochemical and physiological parameters of rice plants, except the number of panicles per plant and biomass. Furthermore, among yield components, interaction effect of cultivar and fertilizer on panicle per plant was significant. Among cultivars investigated, “Fajr” showed the highest panicle length, number of grains per panicle and panicle per plant, leaf area, chlorophyll content, photosynthesis rate, respiration, stomatal conductance, harvest index and grain yield, whereas it had the shortest overall plants height. NPK + micro fertilizer treatment, also, had the most positive effect on production units in rice plant particularly chloroplast function, which eventually resulted in grain yield. Moreover, the combination of micro and macro nutrients facilitated the rate of CO2 and O2 exchange. Therefore, “Fajr” cultivar with more leaf area showed better efficiency in absorption of receipted lights and finally, because of high harvest index, transferred more assimilates into grains.