Crop management for optimal low-linolenic rapeseed oil production Field experiments and modelling
Oil of conventional rapeseed varieties with 7-10 ％ linolenic acid content can be oxidized when heated, resulting in unpleasant odour. Varieties with low (around 3 ％) linolenic acid content have been bred to provide industries with new raw material for frying media production.However, the low-linolenic character can be compromised if the low-linolenic rapeseed field is polluted by conventional varieties through pollen flow or volunteers. Therefore, harvest quality can be compromised by ⅰ) nearby fields of conventional oilseed rape, ⅱ) volunteers of conventional rapeseed growing in a low-linolenic field or in nearby fields. Crop management practices as crop rotation, weed control, soil tillage, varieties and field pattern might be decisive.The Genesys model (Colbach et al., 2001) was initially developed to quantify the effects of cropping systems on gene flow between Genetically Modified (GM) and non-GM crops. In this work, the model was used, after adequate improvements, to predict linolenic content of rapeseed harvests, particularly low-linolenic ones, in different situations.Field experiments carried out at the experimental station in Changins (VD), Switzerland in 2004 and 2005 and observations made on farmers fields showed that beyond 50 meters of distance, a field of conventional rapeseed caused only a minor increase in C18:3 content of a neighbouring low-linolenic rapeseed field. After 20 meters, contamination estimated from linolenic acid increase was about 1％. According to simulations, the presence of volunteers of conventional rapeseed in the low-linolenic field had the most dramatic effect: in a short crop rotation an important amount of volunteers significantly increased the linolenic acid content. In Switzerland, oilseed rape is usually grown with a longer interval than every four years in normal crop rotations, which is usually enough to prevent major contamination by volunteers if the latter are correctly managed. It is however important to be very cautious not to mix seeds of low linolenic rapeseed with conventional rapeseed before sowing or during and after harvest.
alpha-linolenic acid content model gene. flow crop management practices
A.Baux N.Colbach D.Pellet
Agroscope Changins-W(a)denswil research station ACW Department Field crops-Grassland CP 1012, 1260 N UMR1210 Biologie et Gestion des Adventices, INRA, 21000 Dijon, France
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
1251-1254
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）