GENETIC VARIATION IN SIMAZINE RESISTANCE IN WHEAT, RAPE AND MUSTARD

Abstract

Summary. The resistance to simazine of a range of varieties of wheat ( Triticum aestivim L.), rape ( Brassica napus L.) and mustard ( Sinapis alba L.) was assessed in glasshouse tests Varietal differences in survival and final weight of survivors were found in all three crops Variability m the time for which individual plants survived was greatest in the two out‐breeding crops, rape and mustard. The 1 % of mustard plants that survived 10 oz/a csimazine were allowed to produce seed in a polycross. These progenies showed a very marked increase m resistance over the unselected controls. There is thus appreciable genetic variation in resistance to simazine both within and between varieties. This is readily available for selection, and could he valuable in extending the selectivity of herbicides. Variation génétique de la resistance á la simazine chez le blé, le colza et la moutarde