Effect of Plant densities and Spraying with Ethephon on Some Growth Characteristics of Sorghum (Var. Bohooth .70)

Abstract

A field experiment was conducted at the research station in Wasit Agriculture Directorate during spring and autumn seasons of 2021 to study the effect of planting density (80000, 66666 and 50000)plant.ha-1 ,three stages of ethephon spraying to(4, 8 and 12) leave per plant-1 and three concenteration of ethephon (0, 800 and 1600 ppm) on growth traits and their relationship with lodging in Sorghum(var. Bohooth .70). The experiment was applied using (R.C.B.D) arranged in split-split-plots with three replications. Plant densities were used as main-plot, while spraying stages were used as sub-plot and ethephon concenterations were used as sub-sub- Plot. Results showed that low plant density resulted in a significant reduction in plant height reached 14.6%, 8.6% in spring season and 7.7% , 4.5% in autumn season compare with medium and high density respectively, plants in low density also produce shorter internodes in lower parts of the stem in contras, Low density resulted in increment in stem diameter, this may be in ture lead to reduce the % of lodging .Spraying of ethephon at high concentration 1600 ppm resulted in decreases of internode length when it's sprayed at 4 and 8 leaves stage. There was significant relationship between increases of ethephon concentrions and the reduction of each, internodes length, % of lodging in contrast, increase of ethephon lead to increase stem diameter especially when it is spray at 8 leave stage. Stage it can be concluded from this study, that it low be contral on excessive vegetative growth at this devriety by using low density of sowing with ethephone spraying during early growth stages to produce economic grain.