Variation and inheritance of erucic acid content in Brassica carinata germplasm collections from Ethiopia

Ethiopian mustard possesses a number of agronomic advantages over other oilseed crops with similar ecological adaptation in Ethiopia. However, its high erucic acid content is undesirable for a vegetable oil. Although efforts have been made to improve its quality, much has to be done to use natural variations that might exist within the species for fatty acid contents. This project was undertaken to study the variability of fatty acid contents, primarily erucic acid, in germplasm collections of Ethiopian origin, with an attempt to develop low (zero) erucic acid genotypes. The study used inbred lines as well as F₂ populations of 10 crosses between six parental lines. A wide variation in fatty acids was found. Oleic acid content varied from 5 to 34% and erucic acid content from 6 to 51%. Linoleic and linolenic acid contents were less variable. The high‐oleic genotypes exhibited not only low erucic but also higher linoleic (25%) and considerably lower linolenic acid (8%) contents. It was possible to classify the F₂ populations with the lowest erucic acid into three distinct classes. While the first class had an erucic acid content of 6–12%, the second and third classes had contents of 18–32% and 36–42%, respectively. The existence of a multiple allelic series of erucic acid in Ethiopian mustard would enable its fixation at zero levels without necessarily going into interspecific crossing.     

Inheritance of reduced linolenic acid content in the Ethiopian mustard mutant N2-4961

The zero erucic acid Ethiopian mustard lines developed so far are characterized by an exceptionally high linolenic acid content in the seed oil. The mutant line N2‐4961, expressing low linolenic acid content in a high erucic acid background, was developed through chemical mutagenesis. The objective of this research was to study the inheritance of low linolenic acid content in this mutant. Line N2‐4961 was reciprocally crossed with its parent line C‐101 and the linolenic acid content of the reciprocal F₁, F₂ and BC₁ generations was studied. No maternal, cytoplasmic or dominance effects were detected in the analysis of F₁ seeds and F₁ plants from reciprocal crosses. Linolenic acid content segregated in 1: 2: 1 ratios in all the F₂ populations studied, suggesting monogenic inheritance. This was confirmed with the analysis of the reciprocal backcross generation. The simple inheritance of low linolenic acid content in N2‐4961 will facilitate the transference of this trait to zero erucic acid lines of Ethiopian mustard.     

Isolation of induced mutants in Ethiopian mustard (Brassica carinata Braun) with low levels of erucic acid

Ethiopian mustard (Brassica carinata Braun) is a potential oil crop for the rain-fed Mediterranean area. However, its usage is limited by the high erucic and high glucosinolate content of the oil and meal, respectively. In the course of a mutagenesis programme, an agronomically good line of Ethiopian mustard was treated with EMS in order to widen the natural variability of nutritional traits in this species. As a result of this programme several low erucic mutants were isolated; two of these mutants showed erucic acid values in the M4 generation in the range 5–10% of total fatty acids. Near-infrared reflectance spectroscopy (N1RS) was successfully applied as a rapid screening method for erucic acid in this breeding programme.     

Allelic variation in linolenic acid content of high erucic acid Ethiopian mustard and incorporation of the low linolenic acid trait into zero erucic acid germplasm

Zero erucic acid germplasm of Ethiopian mustard is characterized by high levels of linolenic acid (about 21%). Two genetic sources of low linolenic acid (N2‐4961 and HF‐186, about 5%), have been developed in a high erucic acid background. The objectives of this research were to study the genetic relationship between the two low linolenic acid lines and to transfer the trait to zero erucic acid germplasm. F1 seed generations from crosses between both lines had higher average linolenic acid concentration than both parents. F2 seeds segregated for linolenic acid content following a continuous variation from 1.8 to 7.4%, exceeding the limits of the parental distribution ranges. Transgressive recombinants with very low linolenic acid concentration (0.7‐2.7%) were confirmed in the F3 seed generation. The results suggested that N2‐4961 and HF‐186 possess alleles for low linolenic acid at different loci. Transgressive low linolenic acid F3 plants were crossed with plants of a zero erucic acid line and a selection for zero erucic, low linolenic acid was conducted. As a result, a zero erucic acid F3:4 line containing 1.5 ± 0.7% linolenic acid was developed.     

Isolation of induced mutants in linseed (Linum usitatissimum) having reduced linolenic acid content

Summary Seeds of Linum usitatissimum cv. Glenelg were treated with either gamma-rays or EMS in an attempt to induce mutations with a lower level of linolenic acid in linseed oil. Two mutant lines were identified in which linolenic acid constituted approximately 29% of the total fatty acid content compared with 43% in seed oil from untreated Glenelg plants. The reduced level of linolenic acid in the mutants is accompanied by an increase in the level of linoleic acid to 30% compared with 18% in Glenelg, but there was no change in the proportions of other fatty acids. These proportions of linolenic acid and linolenic acid are respectively the highest and lowest yet reported in stable genotypes of L. usitatissimum. The strong inverse relationship between these two fatty acids in these genotypes suggests that linolenic acid is synthesised by desaturation of linolenic acid and indicates that it may be possible to breed an edible linseed oil having both low levels of linolenic acid and high levels of linolenic acid.     

Increasing erucic acid content in Ethiopian mustard through mutation breeding

Ethylmethane sulphonate (EMS) was applied to seeds of the Ethiopian mustard (Brassica carinata A. Braun) line C-101. Bulk samples of M₃ seeds from 8331 M₂ plants were evaluated for the fatty acid composition of their oil by near-infrared reflectance spectroscopy (NIRS) and by further gas chromatography on selected samples. A putative mutant, N2-6230, showing very low oleic acid content (4.7% vs. average of 8.6% in C-101) and erucic acid content within the range of variation of the line C-101 (40-49.3%) was identified. The M₃ progeny of this mutant showed a wide segregation for erucic acid content (39.1-57.9% vs. 41.8-50.3% in C-101), and maintained levels of oleic acid lower than in line C-101. Selection for high erucic acid content in the M₃ and M₄ generations led to the fixation of this mutation in the M₅ generation (52.2-59.3% vs. 39.0-47.6% in C-101). This is the first high erucic acid line obtained in Brassica species through mutation breeding. Its utility in future programmes to develop very high erucic acid lines is discussed.     

Effect of Nitrogen and Sulphur Application on Yield and Fatty acid Composition of Mustard (Brassica juncea L.) Oil

The effects of nitrogen and sulphur on the yield and fatty acid composition of mustard ( Brassica juncea L.) oil were studied in a field experiment. Significantly higher grain and oil yields were obtained with N and S application. Applications of nitrogen up to 60 kg ha⁻¹ and sulphur up to 40 kg ha⁻¹ favourably influenced the grain yield. Increasing levels of N decreased the oil content while application of sulphur improved the oil content. The contents of linoleic and linolenic acid were maximum (16.82 and 8.73%, respectively) with 60 kg N along with 40 kg S ha⁻¹. No use of fertilizers led to higher contents of undesirable fatty acids such as palmitic (hypercholesterimic) and erucic (do not have food value) acids.     

野生和栽培大豆种质油脂组成特点及其与演化的关系

以58份不同类型(野生、半野生和栽培)大豆种质为材料,利用32对SSR标记分析大豆种质间的遗传多样性和进化关系,采用NIRS和GC方法分别分析大豆脂肪含量和脂肪酸组分含量,研究不同类型大豆种质油脂组成特点及其与演化的关系。结果显示,野生大豆和栽培大豆的油脂组成存在显著差异,栽培大豆脂肪含量(平均20.8%)显著高于野生大豆(平均10.49%),油酸含量(平均28.5%)显著高于野生大豆(平均14.37%),而亚麻酸含量却显著低于野生大豆;由相关性分析可知,大豆种子中的脂肪与油酸含量显著正相关(r=0.85^**),而与其他脂肪酸组分极显著负相关;油酸与所有其他脂肪酸组分均负相关,特别是与亚麻酸和亚油酸呈极显著负相关(r=.0.90^**和.0.89^**);油脂组成和SSR标记对不同类型大豆种质的聚类和主成分分析表明,2种分类结果基本一致,可分为栽培和野生2个亚群,半野生大豆则分布于2个亚群中。由此可见,大豆油脂组成与大豆种质的驯化程度有关,脂肪含量和亚麻酸含量可以作为大豆演化分类的参考指标。     

Intraspecific breeding for reduced glucosinolate content in Ethiopian mustard (Brassica carinata A. Braun)

A total of six Ethiopian mustard ( Brassica carinata A. Braun) lines showing reduced levels of total glucosinolate content were developed through two different approaches. In the first case, eight lines with good agronomic performance under southern-Spanish conditions were first evaluated during two years for glucosinolate content, and a pedigree selection was then performed during three further generations. The line N2-142, with an average glucosinolate content of 82 μmoles g-1 seed, was developed from the original line C-49, with an average glucosinolate content of 115 μmoles g-1 seed. In the second case, chemical mutagenesis (EMS 1% v/v) was applied to seeds from the line C- 101, with an average glucosinolate content of 125 μmoles g- 1 seed. Five mutant lines showing an average glucosinolate content between 20 and 30 μmoles g-1 seed lower than the wild line C-101 were isolated in the M_3 or M_4 generation. The reduced glucosinolate content of these mutants was confirmed by developing and analysing the M_5 generation. Previous results in B. juncea suggest that a further reduction of total glucosinolate content might be achieved through genetic recombination between the different lines developed in this work. This revised version was published online in July 2006 with corrections to the Cover Date.     

续随子种子油提取工艺响应面法优化及成分分析

确定续随子种子油的最优提取工艺,并对其脂肪酸成分进行分析。通过比较索氏法、超声法、水酶法对续随子种子油的提取效率,选出最佳提取方法。在单因素试验基础上,采用Plackett-Burman 设计筛选索氏提取法中影响提取率的因素。以种子油提取率作为响应目标,对筛选出的因素通过中心复合设计(Central Composite Design)进行优化,确定索氏提取法的最优提取工艺。三种方法的最高得率分别为41.97%,36.38%,34.33%。提取溶剂、液料比、温度、时间为影响最明显的因素。确定了索氏提取法的最优提取工艺为：提取溶剂石油醚,液料比30:1(v:m),提取温度90℃,提取时间9 h。采用气相色谱-质谱法(GC-MS)分析种子油成分,共鉴定出8 种脂肪酸,占总脂肪酸含量的99%以上。其中,不饱和脂肪酸以油酸、亚油酸、α-亚麻酸和花生酸等为主,其含量达到总脂肪酸90%以上。在此工艺条件下,续随子种子油得率理论值为54.353%,实测值为54.175%,与理论值相比,相对误差为0.120%。研究结果可为续随子种子油的提取工艺提供参考,为续随子的进一步开发利用建立基础。     

New mutants of winter rapeseed (Brassica napus L.) with changed fatty acid composition

Seeds of the winter oilseed rape (Brassica napus L.) line PN 3756/93 were treated with ethyl methanesulphonate to induce mutations in the fatty acid biosynthetic pathway. The seed mutagenic treatment was repeated in the M₂ generation. After treatments, individual seed and plant selections were made for changes in fatty acid composition during several generations of inbreeding. Self‐pollinated plants with changed fatty acid compositions were inbred to obtain genetically homozygous and stable mutant lines. Two mutants, M‐10453 and M‐10464, with increased levels of oleic acid (approximately 76%) and reduced linoleic and linolenic acid contents (8.5% and 7.5%, respectively) were selected. Gene or genes controlling desaturation of oleic acid were probably mutated in these plants. The third mutant, M‐681 had a very low linolenic acid content (approximately 2.6%) and increased linoleic acid content (approximately 26%). This would suggest the occurrence of mutations in genes controlling linoleic acid desaturation. The results of selection work during several generations showed that the environment had substantial influence on the composition of seed oil. This made the search for mutants with modify fatty acid compositions difficult. The induced mutants are not directly usable as new varieties, but can be used as parents in crosses for the development of high quality rapeseed varieties.     

Selection on pollen for linolenic acid content in rapeseed, Brassica napus L.

In order to enhance the economic value of edible rapeseed oil, an improvement of quality is necessary. Mutagenesis of rapeseed resulted in a low linolenic acid content and a low ‘linolenic acid (CIS: 3) level to linoleic acid (CIS: 2) level’ ratio, that is, the linoleic desaturation ratio (LDR), in the seeds of the Canadian variety ‘Stellar’. As an early breeding marker for low linolenic acid content, the pollen fatty acid composition was determined on 80 doubled haploid plants derived from a single F₁ hybrid obtained from a cross between ‘Stellar’ and a high CIS: 3 variety ‘Drakkar’. Fatty acid analysis on seed and pollen showed that the low CIS: 3 and the low LDR traits from the ‘Stellar’ variety were expressed in pollen and in seeds, and that a very close correlation (r = 0.88) existed between seed and pollen for these two traits. The inheritance of these traits is controlled by two major genes with additive effects, both in seed and pollen. However, minor genes also appeared to be expressed in pollen and seed. These genes may allow the production of plants with lower CIS: 3 levels than that of the low linolenic acid content parent. The efficiency of this new tool for early screening in breeding programmes is discussed.     

Selection for contrasting tocopherol content and profile in Ethiopian mustard

Tocopherols are compounds present in oilseeds with major effect on nutritional and technological properties of seed oils. Brassica spp. mainly contain varying concentrations of α‐tocopherol, with high vitamin E value, and γ‐tocopherol, which contributes to oil stability. The objective of this research was to select for contrasting tocopherol content and profile in Ethiopian mustard (Brassica carinata A. Braun). A collection of 211 F_4:5 lines was evaluated for tocopherol content and profile, and divergent selection was conducted till the S_3:4 generation. Selection resulted in two lines with increased tocopherol content (244 and 243 mg/kg seed as average of four environments), one line with reduced tocopherol content (117 mg/kg), two lines with reduced α/γ‐tocopherol ratio (0.22 and 0.28) and two lines with increased α/γ‐tocopherol ratio (3.74 and 3.34). Control line C‐101 averaged 196 mg/kg with α/γ‐tocopherol ratio of 1.10. Reduced α/γ‐tocopherol ratio was controlled by recessive alleles at a single locus. Seed to plant correlation was high (r = 0.92), which suggests the feasibility of selecting at the single‐seed level.     

菜籽油在常温储存过程中品质变化的研究

对不同产地的菜籽油在常温储存条件下的水分及挥发物含量、酸值、过氧化值、色泽及脂肪酸组成变化进行了研究。结果表明:在常温储存的100d内,水分及挥发物含量、色泽随储存时间的延长几乎没有发生变化,亚麻酸含量有微量的减小;酸值随储存时间的延长增长幅度很小,增长率仅为6.3%;而过氧化值随储存时间的延长增长很明显,平均增长率为27.2%,过氧化值是表征菜籽油在储存过程中品质变化的一个最敏感指标。     

不同品种紫苏种子营养成分及脂肪酸组分分析

为了给优化种质资源改良提供理论依据,选用10个不同紫苏品种作为供试材料,研究其种子性状、品质、脂肪酸组成及含量,并对其相关性进行分析。结果表明,10个不同品种紫苏种子直径、千粒重、粗脂肪、粗蛋白和纤维素含量均存在显著差异,变幅为籽粒直径1.58~2.15 mm,千粒重2.36~5.12 g,粗脂肪34.0%~45.2%,粗蛋白18.5%~21.8%,纤维素19.0%~25.1%。总脂肪酸中含棕榈酸3.16%~4.77%,硬脂酸0.56%~1.86%,油酸11.42%~23.06%,亚油酸8.53%~13.02%,亚麻酸58.48%~70.90%,总不饱和脂肪酸占到总脂肪酸的93.26%~95.00%。ZY-3,ZY-1,ZB-1,BZ-2和BS-1粗脂肪含量高,α-亚麻酸比例大,可作为高油高亚麻酸优质育种材料。试验结果还表明,粗脂肪、亚麻酸含量与籽粒直径和千粒重间均呈显著正相关,油酸含量与籽粒直径和千粒重间呈显著负相关,而油酸与亚麻酸含量间呈极显著负相关。因此,要提高紫苏籽的亚麻酸含量,就要适当控制其油酸含量。     

杭白芍结实性状及籽油品质分析

分析杭白芍结实性状及其籽油品质,为芍药籽油专用品种培育及籽油开发利用提供理论参考。对杭白芍的结实性状相关性和籽油理化性质进行测试和分析,结果表明：（1）单心皮种子数和心皮长均与单株产量呈极显著正相关,蓇葖果数与单株产量呈显著正相关,分株数与单株产量呈显著负相关;主成分分析表明,前4个主成分累计贡献率达88.8768%。（2）籽油测试结果表明,种子含油率21.31%,油酸40.56%,亚油酸29.16%,亚麻酸22.11%,籽油不饱和脂肪酸91.83%,维生素E含量79.64 mg/100 g。因此,在选育高产品系时要重点关注单心皮种子数、心皮长和蓇葖果数等性状指标。杭白芍籽油具有较高的食用价值,可以作为一种新型的油料作物,具备深入研究推广的价值。     

3种不同提取方式对红树莓籽油成分的影响

通过超声辅助乙醇提取法、超声辅助石油醚提取法和索氏石油醚提取法3种方法提取红树莓籽油,比较提取率、鉴定脂肪酸成分、测定抗氧化活性和总皂甙含量。结果表明:UAE-Et红树莓籽油的提取率最高,为18.55%,UAE-PE和SE-PE的提取率分别为10.18%和13.58%。GC-MS结果表明,3种提取方法共在红树莓籽油中鉴定出32种物质,其中不饱和脂肪酸(亚油酸和亚麻酸等)含量分别为82.71%(UAE-Et)、85.76%(UAE-PE)和88.83%(SE-PE),均超过80%;ω-6/ω-3脂肪酸比例为2.22∶1~2.32∶1。抗氧化活性研究表明,UAE-Et红树莓籽油抗氧化活性最强,其IC 50(半抑制浓度)为4.36 mg·mL^-1。总皂甙含量测定结果表明,UAE-Et红树莓籽油中总皂甙含量最高,为351.88 mg·g^-1,这与GC-MS吻合。     

Breeding for Modified Fatty Acid Composition by Induced Mutations in Linseed (Linum usitatissimum L.)

Seeds of linseed (Linum usitatissimum L.) cultivars ‘Raulinus’ and ‘Bionda’ were treated mutagenically with ethyl methanesulfonate (EMS) in order to broaden the variation of fatty acid composition in the seed oil and to select mutants with reduced linolenic acid (C18: 3) content. The M₂ generation was evaluated for fatty acid composition of the oil. Genetic variation for unsaturated fatty acids was demonstrated to be extended in the M₂ generation as compared to the controls. Finally in the M₅ generation of cv. ‘Raulinus’, lines with reduced C18:3 (< 40% vs. 55%) and correspondingly increased linoleic or oleic acid contents, respectively, could be selected. These mutants proved to be genetically stable as demonstrated by parent-offspring (M₄/M₅) regression.     

紫苏二酰基甘油酰基转移酶2基因克隆与功能研究

二酰基甘油酰基转移酶(diacylglycerol acyltransferase, DGAT)是植物合成三酰甘油(TAG)最后一步的关键酶,其中DGAT2在某些植物的种子油中能选择性积累更多不饱和脂肪酸。本文成功克隆了紫苏二酰基甘油酰基转移酶2基因(PfDGAT2),并进行生物信息学分析。PfDGAT2实时荧光定量结果表明,不同器官中PfDGAT2基因均有表达, 10 d种子的表达量最高,在根中的表达量次之,在种子发育中后期,PfDGAT2表达量逐渐降低。与野生型拟南芥相比,过表达PfDGAT2拟南芥种子含油率提高了21.68%～77.89%,其中种子含油率增加最多的4个株系,其亚麻酸(C18:3)增加4.57%,花生一烯酸(C20:1)增加7.44%,花生二烯酸(C20:2)增加5.4%,二十二一烯酸(C22:1)增加10.37%,而棕榈酸(C16:0)、硬脂酸(C18:0)和亚油酸(C18:2)含量分别降低了3.47%、6.64%和4.83%,油酸(C18:1)和花生酸(C20:0)分别只降低了0.18%和1.91%。本研究结果表明,紫苏PfDGAT2基因不仅能提高种子含油率,还...     

亚麻籽油的开发利用

亚麻是山西省高寒山区的主要油用作物之一。亚麻籽含油率达到42%,油中不饱和脂肪酸占到主要脂肪酸组成的91%,其中,ω-3脂肪酸含量高达49%,比其他油用作物含量高7倍～50倍。ω-3脂肪酸营养油具有预防冠心病、心脑血管病,降低胆固醇,抗血栓,降血压,提高动脉系统柔性的功能,极具开发价值。ω-3脂肪酸营养油是在常规油脂加工工艺基础上,通过对部分工艺的改进,使产品中α-亚麻酸的含量较传统工艺提高了38.9%。