Identification of faba bean lines tolerant to high dosage of Glyphosate

Abstract

Orobanche'crenata' Forsk is a parasitic weed that invades faba bean (Vicia faba L.) in the North Africa, East Africa and the Middle East. Several control methods including chemital, mechanical, cultural and even induction of resistance in faba beans have been developed. Presently, an integration approach involving chemical control by glyphosate fN-(phosphonomethyl) glycine] and varietafresistance is the most effective technique. However, phyotoxicity slnrrptoms accorpanied by significant yield losses have been reported on faba beans at the recommended dose (200 g a.i.lha).In this study, we evaluated tolerance of 290 mutagenized faba bean lines against three glyphosate treatments; T 1 : 8d0 g a.i.lha; T2: 1200 g a.i.lha; T3: 1600 ga.i.lha under field conditions at the flowering stage. The experimental design used was augmented design with three replicate checks every 9 lines. Observations were recorded on chlorosis, rolling of apical leaves, reduced growth, lower number of pods and mortality. Some of the mutant lines showed very high tolerance against tested doses of glyphosate; 66 mutant lines against 800 g a.i.lha, 22 againsl 1200 g ai.Aa and 2l ar 1600 g a.i.lha of glyphosat€. Two mutant lines, Mu-3 8 and Mu-41 8 showed tolerance at the three tested doses of gllphosate in terms of growth and seed yield.