Diclofop-methyl tolerance in cultivated oats (Avena sativa L.).

Warkentin, T. D.; Marshall, G.; McKenzie, R. I. H.; Morrison, I. N.

The feasibility of achieving selective wild oat (<em>Avena fatua L.</em>) control in a stand of the Australian oat (<em>Avena sativa L.</em>) cv. Savena 1 was examined. Diclofop-methyl was applied at rates of 0.4-0.7 kg a.i. ha-1 at the three- and five-leaf stages of <em>A. fatua</em> (84-132 culms m²). Although all rates of diclofop-methyl caused initial chlorosis and necrosis to the crop, the subsequent control of <em>A. fatua</em> permitted increased crop tillering. <em>Avena fatua</em> control and crop yield response were maximized when diclofop-methyl was applied at the three-leaf stage. Crop grain yield was increased by as much as 32% and 22% during 1984 and 1985, respectively. In the absence of <em>A. fatua</em> competition, crop shoot dry weight at ear emergence was reduced only where diclofop-methyl was applied at 0.6 or 0.7 kg ha-1. However, final grain yield was not reduced by any treatment. Only 11 of 240 cultivars or lines tolerated diclofop-methyl, and none reached the level attained by Savena 1 and a closely related Australian line [(Irwin x (West x New Zealand Cape/42)) x West]/24. The nature of the inheritance of diclofop-methyl tolerance was examined (1983-1985) by crossing and backcrossing (BC) Savena 1 with four diclofop-methyl susceptible, but agronomically superior, lines. Inheritance of diclofop-methyl tolerance appeared to be controlled by two genes, with susceptibility being dominant to tolerance in F3, BCIF2 and BCIF3 lines.

WILD oat; OATS; WEEDS; CHLOROSIS (Plants); NECROSIS

Weed Research, 1988, Vol 28, Issue 1, p27

0043-1737

Academic Journal

10.1111/j.1365-3180.1988.tb00782.x