Origin and economic importance of oilseed rape
Oilseed rape (Brassica napus L.) is the most economically important species within the
The Brassica genus has been extensively studied over the past 30 years, primarily for its role as an oilseed crop, including rapeseed and canola, as well as swede and various fodder and vegetable crops Recently, it has gained attention as a renewable feedstock for biodiesel production B napus morphotypes demonstrate significant adaptability to various eco-geographical regions, making them a valuable model for researching crop evolution and adaptation The cultivation of rapeseed originated in Europe during the Middle Ages and has since expanded globally (Chalhoub et al., 2014).
Brassica napus L (2n = 38, genome AACC) is a recent allopolyploid species formed through hybridization between turnip rape (Brassica rapa L., 2n = 20, genome AA) and cabbage (Brassica oleracea L., 2n = 18, genome CC), resulting in an amphidiploid genome that contains the complete chromosome sets of both progenitors This species is believed to have originated in the coastal Mediterranean region, where its parental species grow wild, as there are no known wild forms of B napus The availability of reference genome sequences for B napus has confirmed its diploid ancestors, B rapa and B oleracea.
In 2017-2018, global rapeseed production surpassed 74.71 million tons, positioning it as the second most valuable source of vegetable oil and protein meal, following soybeans This significant growth in production is primarily due to intensive breeding efforts aimed at reducing erucic acid and glucosinolate levels, which have enhanced its value as both edible oil and livestock feed.
The Brassica triangle illustrates the relationships among species, highlighting that Brassica napus (2n=38) originated from spontaneous interspecific hybridization between its two diploid progenitors This information is sourced from Snowdon's 2007 study published in Chromosome Research.
Rapeseed oil, known for its low erucic acid content of less than 2% (Low Erucic Acid Rapeseed, LEAR), features a favorable fatty acid profile with a 2:1 ratio of linoleic to α-linolenic acid It boasts the lowest levels of saturated fatty acids among major vegetable oils, while approximately 60% of its total fatty acids consist of the beneficial monounsaturated fatty acid oleic acid.
Rapeseed oil is considered one of the most nutritionally valuable vegetable oils due to its unique composition Recent advancements have led to the development of high oleic/low linolenic acid (HOLL) varieties of B napus, making it ideal for high-temperature frying and margarine production These varieties help reduce trans fatty acids, contributing to the prevention and treatment of chronic diseases, particularly lowering the risk of coronary heart disease.
Figure 2: World production of major oilseed crops in 2017-2018 (FAOSTAT data, 2017-
The introduction of rapeseed cultivars with less than 30 micromoles of glucosinolate per gram marked a significant advancement in breeding In 1974, the first 00-quality spring rapeseed variety, Tower, was released, featuring zero erucic acid and low glucosinolate levels This innovation led to the development of double low varieties, enhancing the quality and safety of rapeseed oil.
Rapeseed cultivars produce a meal by-product from oil extraction that contains 36 to 44% crude protein and offers a well-balanced profile of essential amino acids, making it an excellent source of animal feed (Snowdon et al., 2007) Additionally, edible rapeseed is the predominant oilseed utilized for biodiesel production in Europe Notably, biodiesel derived from rapeseed oil has superior cold-weather performance, as it gels at lower temperatures compared to biodiesel from other feedstocks, making it an ideal fuel choice for colder climates (Peterson et al., 1997).
In the 2017-2018 production year, global rapeseed output reached approximately 68.86 million tons, with Canada (18.42 million tons), China (15.28 million tons), India (6.80 million tons), France (4.72 million tons), and Germany (4.58 million tons) being the top five producers, collectively accounting for over 72% of the total production Winter oilseed rape is primarily grown in Europe and Asia, while spring oilseed rape is better suited for Canada, northern Europe, and Australia, with varietal selection influenced by climatic and phenological conditions The average yield globally was 2.04 tonnes per hectare, varying significantly across regions, with Western Europe achieving up to 3.45 tonnes per hectare, followed by Canada at 2.31, China at 2.01, and lower yields in Australia (1.25) and India (1.18 tonnes per hectare).
Figure 3: World leading producing countries of rapeseed in 2017-2018 (FAOSTAT data,
Current breeding aims of oilseed rape
The primary objectives of oilseed rape breeding focus on enhancing tolerance to late planting and winter hardiness, improving plant height and lodging resistance, and developing resistance to diseases such as blackleg, Verticillium wilt, and ideally Sclerotinia Additionally, breeders aim for very low levels of erucic acid and glucosinolates, alongside high oil content and marketable seed yield (Friedt and Snowdon, 2010) Recently, achieving good germination and seedling vigor has also become a significant breeding target in B oleracea (Bettey et al., 2000).
Morris et al., 2016), B rapa (Basnet et al., 2015) and B napus (Hatzig et al., 2015;
Nguyen et al., 2016; Nguyen et al., 2018) because seedling vigour and prewinter crop establishment are closely associated with post-winter growth and seed yield
Table 1: Four major fields and associated detail traits of oilseed rape breeding
Agronomic traits play a crucial role in crop performance, encompassing disease and pest resistance, tolerance to late planting, and winter hardiness Key characteristics include plant height and lodging resistance, early maturity, nutrient efficiency, and drought tolerance Additionally, shattering and herbicide tolerance are vital for successful cultivation Good germination and seedling vigor are essential, along with resistance to diseases such as Phoma, Verticillium, and Clubroot, while Sclerotinia resistance needs further identification Furthermore, virus resistance, particularly to TuYV, and the identification of resistance to various insect pests are critical for enhancing crop resilience and productivity.
The yield potential of seeds is significantly influenced by their quality, which includes high oil content suitable for edible and biofuel oils Key components such as seed yield, harvest index, and total marketable seed yield are essential for assessing performance Additionally, traits like herbicide tolerance, very low erucic acid content (C22:1