Resistance and Quality Breeding in Winter Oil Rapeseed


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Resistance and Quality Breeding in Winter Oil Rapeseed

  1. 1. Resistance and Quality Breeding in Winter Oil Rapeseed Bharati Singh June 19, 2014
  2. 2. Bharati Singh - Resistance and Quality Breeding in Winter Oil Rapeseed 1 1 Introduction Winter rapeseed (Brassica napus) is one of the significant agricultural crop which is grown commonly for production of oil and biofuel. After the extraction of the oil, oil cake which contains high protein can be used for animal feed. It is mainly grown in Europe, Asia, North America and Australia. It is generally produced in a crop rotation including winter wheat and barley. This contributes in decreasing the occurrence of root diseases and increasing organic matters in the soil. It is believed that the nutritional requirement of crop is the most significant factor. The nitrogen plays a very important role in intensifying the yield. In one of the studies, Hocking, et. al. [1] published that the requirement of nitrogen by rapeseed in comparison to wheat is 25% more. The yield response of the rapeseed with increasing nitrogen concentration in soil varies with different environmental factors, like weather, soil type, residual fertility of the soil, water content and cultivar. Many of the studies have pointed out that the both growth and yield of the rapeseed are increased remarkably by high dose of applied nitrogen. Nitrogen enhances yield by regulating many growth factors, such as number of branches and pods per plant seeds per pod. Selecting an adequate dose, source and timing of nitrogen fertilizer application and the gap between the sowing of the seeds are notable aspects for the promising production of rapeseed [2]. 1.1 Fluorobiology of rapeseed The flower is radial having four petals, four sepals and six stamens. Out of the six stamens, two of the stamens are short which face outside than the inner ones which surrounds the stigma. The yellow colour of leaves attracts insects. The pollination could be either self pollination or cross pollination. The studies have shown that the cross pollination increases seed yield which results in increase of oil content and heavier seeds [3]. The cross pollination reduces inbreeding depression. It also results in gene exchange. 1.2 Plant architecture The rapeseed is an annual herbicide plant consisting of 1-2 cm high erect stem branches, and long thin tap root. The flowers are yellow in colour and are present in bunch on the shoots in the form of racemes [4]. The branching of the plants enables to compensate the gap in the field. This makes rapeseed very flexible and adaptable. Further, the branching contributes to the stability of the plant. Generally 50 to 70 seeds are sown per square meter. The immature seeds are elongated pods and green in colour which, finally, turns into brown. Each pod contains up to 20 seeds. The brown colour of the seeds at the maturity is due to the
  3. 3. Bharati Singh - Resistance and Quality Breeding in Winter Oil Rapeseed 2 presence of phenolic compound, tannin. 1.3 Harvesting Determining harvesting period is very hard. This is not only because of long flowering period but matu- ration is also irregular. The most ideal time of harvesting is when the first pod cracks which are present on the main stem. The lower moisture content in the seeds helps in saving cost for drying up seeds to the adequate parameters. In Germany, harvesting is completely machine dependent. The yield of the rapeseed in Germany is 4-5 million tonnes per hectare. 2 Aspects of Quality Breeding 1. Reduction of anti-nutritional factors (a) Glucosinolate content: It is a secondary metabolite which occurs in most of the plants of the order Brassicales. The glucosinolates provide bitter taste. Genotype, developmental state, en- vironment and age of the plant have great impact on the content of glucosinolates. It is present in many parts of plants like root, stems, leaves but their highest occurrence is seen in the seeds. The hydrolysis of glucosinolate results in the production of many goitrogenic and toxic com- pounds. The enzyme responsible for this is myrosinase [5]. The hydrolysis results in the forma- tion of isothiocynate, thiocynate and nitrile. The goitrin produced interferes with the secretion of thyroxine hormone. Therefore, the rapeseed oil is harmful for the person suffering from hypothyroidism. (b) Tannine content: In rapeseed, the tannine causes dark colour of seed coat and they deposits in the endothelium cell layer between outer integument and aleuronic layer. It can have major influence on animal nutrition because of their capability to form indigestible bitter tasting com- plex with protein. One possibility to minimize this problem can be done by breeding rapeseed with reduced tannins which occur in seed coat [6]. (c) Sinapine: It is a choline ester of sinapic acid. It has several unsatisfactory properties to animal feed like bitter taste, which make it less acceptable to animals. The presence of sinapine at the level of 1gm/kg, in the diet of certain brown egg laying hens, results in fishy odour or taste in their eggs.
  4. 4. Bharati Singh - Resistance and Quality Breeding in Winter Oil Rapeseed 3 (d) Phytic acid: It is one of the main components of all plant seeds and has great affinity to bind positively charged molecules like cations and proteins. The interaction between phytic acid and minerals results in the formation of complex molecules which are insoluble at the pH which oc- cur in intestines. Therefore, adsorption becomes hard. Further, the complex molecules between protein and phytic acid may also have negative effect on the enzymatic digestion of protein. 2. High oil content and high yield (a) 00 quality: Zero euric acid is essential when rapeseed oil is used as food oil. Low glucosinolate content is necessary when used as animal feed. High erucic acid rapeseed (HEAR) + 0 quality varieties are cultivated for industrial purpose. In Germany, it is cultivated on around 20,000 hectare. (b) HOLLI types: This is the special variety having higher content of oleic acid (up to 80%) and reduced content of linolenic acid (less than 4%). It makes suitable for its use at high temperature and cooking. Post flowering temperature are believed to have great impact on the composition of fatty acid in many oil seed crop species. The yield also depends on factors such as number of pod per plant and seeds per pod. (c) Omega 3 fatty acid: In the rapeseed oil reduces the risk for heart disease. It is also rich in vitamin E which act as antioxidant and reduces the risk for cancer disease. Other aspects of quality breeding include shortness of stems, stem stiffness, earliness of flowering and maturity. 3 Aspects of Resistance Breeding 1. Blackleg diseases: This is the main disease occurring in Brassica crops such as cabbage, turnip and rapeseed. This disease is caused by L. maculans. For the first time it was observed on the stem of red cabbage. Winter and spring crops, both types, are damaged by blackleg disease mainly in Australia, Europe and North America. This pathogen is capable to kill plants even at the seedling stage, infecting cotyledons, leaves, stems, roots, pods. Therefore, control of occurrence of Blackleg disease is one of the important breeding programs. Symptoms of this disease are leaf lesions and stem canker. The onset of fungus is represented by dirty whitish spot on the leaves with small dark fruiting bodies. Usually black lesions are also seen
  5. 5. Bharati Singh - Resistance and Quality Breeding in Winter Oil Rapeseed 4 on the leaves. It can also occur on pods and results in premature pod shatter. During the infection stage, the pathogens move downward towards the tap roots of the plants [7]. 2. Clubroot disease: This disease is a soil borne disease which is caused by plasmodiophora brassicae. Research has shown that infection of 90% of the plants leads about 50% loss in seed yield and also remarkable reduction in seed oil content and an enhancement in chlorophyll content are generally correlated with the onset of this disease [8]. When plant root is invaded by fungus, it causes imbalance of hormone which results in increased cell division and growth, and forms characteristic crown galls. 3. Verticilium wilt: One of the most significant pathogen of oilseed rape in Europe is Verticillium longis- porum, which is a soil borne, vascular fungal pathogen that infects roots and leads to premature ripen- ing of the seeds [9]. This fungus is capable to survive for many years in the soil and block nutrient flow. Use of fungicides is not promising. Therefore new resistant cultivar line is required to prevent losses to the seed yield caused by pathogen [10]. 4. Sclerotinia stem rot: This is caused by the fungal pathogen sclerotinia sclerotiorum which is a serious problem in Germany and other European countries. Plant is generally manifested by pathogen as mycelia or airborne ascospores. Although partial resistance against the disease has been achieved but fully or highly resistant line has not been achieved yet. 3.1 Breeding methods in oil seed rape (a) Resynthesized rapeseed (b) Line breeding (c) Hybrid breeding (d) Male sterility system The Hybrid varieties are produced by crossing a female plant which does not produce pollen. It means they are male sterile with a male plant that produce pollen. This restores100% male fertility. References [1] P. Hocking, P. Randall, and D. DeMarco, “The response of dryland canola to nitrogen fertilizer: partitioning and mobilization of dry matter and nitrogen, and nitrogen effects on
  6. 6. Bharati Singh - Resistance and Quality Breeding in Winter Oil Rapeseed 5 yield components,” Field Crops Research, vol. 54, pp. 201–220, 1997. [Online]. Available: [2] O. ¨Ozt¨urk, “Effects of source and rate of nitrogen fertilizer on yield, yield components and quality of winter rapeseed (brassica napus l.),” CHILEAN JOURNAL OF AGRICULTURAL RESEARCH, vol. 70, pp. 132–141, 2010. [Online]. Available: [3] R. Bommarco, L. Marini, and B. Vaissiere, “Insect pollination enhances seed yield, quality, and market value in oilseed rape.” Oecologia, vol. 169, pp. 1025–1032, 2010. [Online]. Available: [4] D. V. Alford, Biocontrol of Oilseed Rape Pests, 1st ed. Wiley-Blackwell, 2003. [5] C. RYMER and F. SHORT, “The nutritive value for livestock of uk oilseed rape and rapeseed meal,” RESEARCH REVIEW NO. OS14, 2003. [Online]. Available: rr os14 - complete final report.pdf [6] F. D. LIPSA, R. J. SNOWDON, and W. FRIEDT, “Qtl analysis of condensed tannins content in brassica napus l.” Research Journal of Agricultural Science, vol. 41, pp. 274–278, 2009. [7] R. Harsh, R. Rosy, and L. Nick, “Genetic dissection of blackleg resistance loci in rapeseed (brassica napus l.),” book - Plant Breeding from Laboratories to Fields, 2013-05-22. [Online]. Available: genetic-dissection-of-blackleg-resistance-loci-in-rapeseed-brassica-napus-l- [8] R. Habibur, Breeding for clubroot resistant spring canola (BrassicanapusL.) for the Canadian prairies: Can the European winter canola cv. Mendel be used as a source of resistance? Cana- dian Journal of Plant Science, 2011, vol. 91. [9] W. Rygulla, W. Friedt, F. Seyis, W. Luehs, C. Eynck, A. von Tiedemann, and R. J. Snowdon, “Com- bination of resistance to verticillium longisporum from zero erucic acid brassica oleracea and oilseed brassica rapa genotypes in resynthesized rapeseed (brassica napus) lines,” PLANT BREEDING, vol. 126, no. 6, pp. 596–602, 2007. [10] C. Eynck, B. Koopmann, and A. von Tiedemann, “Identification of brassica accessions with enhanced resistance to verticillium longisporum under controlled and field conditions,” Journal of Plant Disease and Protection, vol. 116, pp. 63–72, 2009.