| Field, greenhouse, and laboratory studies were initiated to determine the response of 22 Italian ryegrass (Lolium multiflorum Lam.), and seven rice (Oryza sativa L.) cultivars to fenoxaprop ;A differential in tolerance was also found for the rice cultivars under greenhouse conditions only. At the 2-leaf growth stage, more than a 4-fold difference in tolerance existed between the least and the most susceptible cultivars. The gain in tolerance with age in rice was greater than that in Italian ryegrass cultivars. Tolerance to fenoxaprop in 4-leaf rice plants was six-times that in the 2-leaf plants. However, in both rice and Italian ryegrass, the age-related gain in tolerance was not proportionate in all the cultivars. Generally higher gain in tolerance was attained by the more tolerant than the susceptible cultivars. In the last phase of research, attempts were made to integrate the whole plant tolerance with the assumed primary target site of fenoxaprop. Evaluated with I;Based on GR... |
