Efficacy of imazamox in imidazolinone-resistant spring oilseed rape in Finland

Abstract

Imidazolinonies (IMIs) are a group of herbicides inhibiting acetolactate synthase (ALS) activity. They control the growth of many broadleaved weeds and annual grass species. Herbicide resistance against imidazolinonies has been transferred in some crop species, for example in Brassica napus. IMI-resistant oilseed rape cultivars have been developed by a mutation in ALS. They have been on the market for a few years, especially in North America. To determine if imazamox, an imidazolinone herbicide, and IMI-resistant oilseed rape cultivars are suitable for cultivation in Finland, we conducted four herbicide trials in three locations. We found, that imazamox had no negative effect on yield or oil quality characters of IMI-resistant oilseed rape. Some transient chlorosis was observed immediately after the treatment, but it was not apparent after a few days. The effects of imazamox against the most troublesome weeds in oilseed field in Finland, Chenopodium album and Galium spurium, were very good. Imazamox had good or moderate effects on Stellaria media, whereas its effects on Viola arvensis, Lapsana communis and Fallopia convolvulus were insufficient. If the total weed number was high or the emergence of oilseed rape was slow, the application of imazamox increased the yield of oilseed rape compared to untreated control. Our results suggest that imazamox is a good alternative in controlling weeds for Finnish oilseed fields. Therefore, it would be beneficial to transfer the IMI-resistance into Finnish oilseed and turnip rape lines.

Plant biotechnology for deeper understanding, wider use and further development of agricultural and horticultural crops

“…One additional example at DAB is the transfer of herbicide (imidazolinone, IMI) tolerance from Brassica napus L. to B. rapa L. by conventional means using hybrid breeding (Haukkapää et al 2005, Niemelä et al 2006. The tolerance of IMI is based on a chemically induced mutation of the acetolactate synthase (ALS) gene in B. napus (Swanson et al 1989).…”

The Biology of Canadian Weeds. 146.Lapsana communisL.

“…However, after centuries of attracting little attention as a weed, it has recently become more weedy and problematic, spreading in a number of cropping systems, including fodder crops, cereals, vegetables, orchards and vineyards, particularly in the eastern and northern parts of its range (Weber and Gut 2005). The species has become an important weed in cereal crops throughout northern Europe including Denmark (Jensen 1991), the United Kingdom (Marshall 1989;Bond et al 2007), Estonia (Vesik 2001;Reintam and Koster 2000), Finland (Raatikainen and Raatikainen 1979; Salonen and Ervio 1988;Salonen 1993;Hyvo¨nen et al 2003;Haukkapa¨a¨et al 2005;Hyvo¨nen 2007), France (Barralis et al 1988), Norway (Semb and Skuterud 1996;Skuterud et al 1998;Berge et al 2008), Poland (Hocho 1990;Wojcik 1998;Snarska 2004), and Sweden (Hallgren 1996).…”

“…The effectiveness of imidazolinones (IMIs), a group of herbicides inhibiting acetolactate synthase (ALS) activity in IMI-resistant canola, was tested at several locations, using imazamox (Haukkapa¨a¨et al 2005). Imazamox was very effective against the most troublesome weeds, but was largely ineffective against L. communis.…”

Imidazolinone Resistance in Oilseed Rape (Brassica napus L.): Current Status, Breeding, Molecular Markers and Prospects for Application in Hybrid Seed Purity Improvement

“…In addition, weed infestation affects the permeability of the rapeseed root system, which leads to an increase in moisture in the above-ground space and creates a favorable environment for pathogen growth and spread, increasing yield losses [11]. On the other hand, the presence of weeds deteriorates the quality of the raw material, as the presence of weed seeds among rapeseed reduces the quality of oil and makes it difficult to process [12].…”