Likening Between the Effect of Drought and Terminal Water‐stress Simulated by a Senescing Agent in Triticale

Abstract

AbstractIn 1994 four field experiments were conducted at two sites (northern and southern Spain), and in two environments at each site (irrigated and dryland conditions) in order to compare the effect of drought with the stress caused by chemical treatment with a senescing agent (potassium iodide, KI). A concentration of 0.3 % of KI was applied 10 days after anthesis on triticale Trujillo (X Tnticosecale Wittmack), and four nearisogenic lines derived from it.The effect of the senescing agent on grain yield was higher in irrigated conditions than in dryland. The reduction in grain yield due to drought was higher than that caused by KI treatment, but both responses were correlated.Drought and KI treatment had a different effect on yield components since water stress previous to anthesis markedly reduced the number of spikes per m2. The effect of the chemical on the number of grains per spike was similar and correlated significantly with the reduction caused by drought. Dry matter accumulation of the grains decreased rapidly following chemical spray due to an important effect of KI on the grain filling rate. No association was found between the reduction in grain weight caused by drought and by KI treatment.