Growth, Photosynthetic Efficiency, Rate of Transpiration, Lodging, and Grain Yield of Tef (Eragrostis Tef (Zucc) Trotter) as Influenced by Stage and Rate of Paclobutrazol Application

The growth response of tef (Eragrostis Tef (Zucc.) Trotter) to foliar spray of paclobutrazol was investigated under sub-humid and hot tropical conditions of eastern Ethiopia. At both locations, paclobutrazol was applied at tillering, jointing or panicle emergence stage at rates of 0, 1, 2, and 3 kg a.i. per ha. The results of the field trials demonstrated that paclobutrazol treatment increased leaf chlorophyll a and b content, reduced the rate of leaf transpiration, and increased photosynthetic efficiency that has a direct effect on the productivity of the tef crop. Paclobutrazol treatment had reduced plant height and total leaf area there by reduced excessive vegetative growth and lodging percentage. Paclobutrazol treatment resulted in increased number of fertile tillers, number of fertile florets per spike, and thousand seed mass there by increasing tef grain yield. It is reasonable to point out that paclobutrazol is a potential plant growth regulator for use as a height-shortening anti-lodging agent in tef with subsequent grain yield benefits. Application of 1 kg a.i. paclobutrazol per hectare seems to be optimum rate and the appropriate stage of application appeared to be between tillering and jointing. Keywords: Eragrostis Tef; Grain Yield; Lodging; Paclobutrazol; Tef East African Journal of Sciences Vol. 1 (1) 2007: pp. 35-4