Interference of feral radish (Raphanus sativus) resistant to AHAS-inhibiting herbicides in oilseed rape, wheat and sunflower crops

Abstract

Raphanus sativus (feral radish), a cosmopolitan weed, has developed resistance to acetohydroxyacid synthase (AHAS) inhibitor herbicides in several countries of South America. This study reports the effects of season-long interference of several feral radish densities on grain yield and yield components of oilseed rape, wheat and sunflower, and on feral radish traits under field conditions. Feral radish density treatments consisted of 0, 2, 4, 8 and 16 plants m−2 in oilseed rape, 0, 4 and 12 plants m−2 in wheat, and 0, 1.6, 4, 8 and 16 plants m−2 in sunflower. The number of inflorescences per area, seeds per inflorescence and the seed biomass of crops were reduced with increasing feral radish densities. The rectangular hyperbola model revealed yield losses by up to 100 %, 74.4 % and 12.2 % in oilseed rape, wheat and sunflower, respectively. Feral radish seed production ranged from 4,300 to 31,200, and 1000 to 4,700 seeds m−2 in winter crops and sunflower, respectively. Season-long feral radish interference can result in serious economic losses in oilseed rape, wheat and sunflower. The adverse impact of feral radish on the yield of winter and summer crops and the high feral radish seed and pods production suggests the need for the development and implementation of diverse and effective long-term weed management practices.

Agricultural weeds: the contribution of domesticated species to the origin and evolution of feral weeds

“…Therefore, not all feral weeds share all traits, suggesting that different genetic backgrounds may evolve weediness through distinct genetic mechanisms 23,38,47 . For example, some populations of weedy rice, feral rye, feral radish, and weedy Brassica rapa have not evolved seed dormancy; 8,46,72,73 feral rye, weedy artichoke and some weedy rice populations have not evolved early flowering; 74–76 and feral radish has not evolved seed shattering 77,78 . However, they are all important feral weeds 3,4 …”

“…In Argentina, feral radish has been considered an invasive weed for at least 80 years and is present in 20 provinces 131 . AHAS‐resistant feral radish is widely distributed throughout the main winter cereal producing area, 77,132 where its interference can cause yield losses up to 74% and 100% in wheat and oilseed rape, respectively 78 . Argentine feral R. sativus populations showed the most morphological traits similar to those of the crop, such as white or purple flowers, swollen roots, pods attached to the mother plant at maturity, a lack of seed dormancy, and do not have the constricted fruits or yellow flowers that are characteristic of the wild relative R. raphanistrum 73,77 .…”