Influence of Shading and Paclobutrazol Concentrations on Growth and Quality Characters of Three Different Turf Grasses Genera

Abstract

This study was carried out in Pirmam,, Erbil Governorate - Iraq for two years, from 15 March 2020 to 15 March 2021 in the spring season and from 15 September2020 to 15 September 2021 in the autumn season, to study the responses of three turf grass genera, includingermuda grass (Cynodon dactylon L. var. cd4), Tall fescue grass (Festuca arrundaceae L. var. Barleroy) and Creeping bent grass (Agrostis palustris) cultivated by seeds to two shading levels of 0 and 75% and sprayed with three paclobutrazol concentrations at 0, 750 and 1500 mg. l-1. The experiment was performed by using Randomized Complete Block Design (RCBD) in a split-plot design with three factors and three replications. The results showed that the shading level (0%) led to a significant increase in most studied characters like mowing number, cumulative dry weight of turf grass clipping yield, dry root weight, total chlorophyll and carbohydrate percentage and was superior to those grown under 75% shading. Both levels of shading had no significant effects on color degree and coverage percentage of the used turf grasses. It also showed that foliar spray of paclobutrazol had a significant impact on those traits. The highest values of plant density, mowing number, and cumulative dry weight of clipping yield were recorded when turf grasses were unsprayed with paclobutrazol, while the highest values of color degree, coverage percentage, total chlorophyll content, and carbohydrate percent were obtained when turf grasses were sprayed with 1500 and 750 mg.l-1 of paclobutrazol, respectively. Significant differences were shown among turf grass genera that were grown from seeds in those traits. Agrostise genus was significantly superior to other genera only in plant density, while Festuca genus was significantly superior to other genera in the rest of the other characteristics. As for triple interactions, the highest significant values for most characteristics were found in Festuca genera that were sprayed with 750 and 1500 mg.l-1 concentrations of paclobutrazol and grown in open fields.