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Diclofop‐methyl tolerance in cultivated oats ( Avena sativa L.)
Author(s) -
WARKENTIN T. D.,
MARSHALL G.,
McKENZIE R. I. H.,
MORRISON I. N.
Publication year - 1988
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1988.tb00782.x
Subject(s) - avena fatua , avena , biology , backcrossing , agronomy , crop , horticulture , weed , gene , biochemistry
Summary The feasibility of achieving selective wild oat ( Avena fatua L.) control in a stand of the Australian oat ( Avena sativa L.) cv. Savena I 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 A. fatua (84–132 culms m 2 ). Although all rates of diclofop‐methyl caused initial chlorosis and necrosis to the crop, the subsequent control of A. fatua permitted increased crop tillering. Avena fatua 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 A. fatua 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 I and a closely related Australian line [(Irwin × (West × New Zealand Cape/42)) × West]/24. The nature of the inheritance of diclofop‐methyl tolerance was examined (1983–1985) by crossing and backcrossing (BC) Savena I 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 F 3 , BCIF 2 and BCIF 3 lines.