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Inheritance of Tolerance to, and Agronomic Effects of, Difenzoquat Herbicide in Spring Wheat
Author(s) -
Busch R.,
Behrens R.,
Ageez A.,
Elakkad M.
Publication year - 1989
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1989.0011183x002900010010x
Subject(s) - biology , cultivar , agronomy , poaceae
The herbicide difenzoquat (1,2‐dimethyl‐3,5‐diphenyl‐1 H‐pyrazolium) has been widely used to control wild oat ( Arena fatua L.) growth in wheat ( Triticum aestivum L.). Different wheat genotypes have been found that are susceptible and tolerant to difenzoquat. Our objectives were to determine the inheritance of tolerance, and the effect of difenzoquat on agronomic traits in spring wheat. Two tolerant (T) and two susceptible (S) spring wheat cultivars crossed in all combinations (reciprocals bulked) to produce six populations. Four hundred sixty‐two F 2 derived F 4 lines were evaluated for herbicide injury when treated at 2✕ (twice) the recommended rate. Three classes of injury level (tolerant, intermediate, and susceptible) were recognized. From one of the four T ✕ S populations, 10 lines for each class were selected. These lines and their parents were exposed to 0, 1✕, and 2✕ rates of difenzoquat for 2 yr, and agronomic traits and herbicide injury were measured. In the genetic study, lines from each of the T ✕ S populations exhibitedifferential herbicide reactions, while the lines within the T ✕ T and S ✕ S populations did not differ. All T ✕ S populations, individually and combined, fit a 3:1 ratio suggesting a single dominant gene for tolerance. However, lines with intermediate tolerance were found, indicating that other genes may modify the expression of tolerance. In the agronomic study, when untreated, the tolerant, intermediate, and susceptible lines did not differ for yield, plant height, or days to head. The 1✕ and 2✕ rates had no apparent effect on agronomic traits of lines in the tolerant class. The intermediate lines yielded 92 and 80% of their untreated check at the 1✕ and 2✕ rates, respectively, while the susceptible lines yielded 69 and 51% as much grain as their untreated check in these treatments. Since no deleterious effects of tolerance were found, its incorporation into susceptible genotypes should pose few problems.