Relationships between seed oil content and fatty acid composition in high stearic acid sunflower

The high stearic acid sunflower mutant CAS-3 is characterized by a low seed oil content, which might represent a constraint for the commercial production of high stearic acid sunflower oil. The objective of the present research was to investigate the relationships between fatty acid profile and seed oil content in CAS-3. Plants of CAS-3 were reciprocally crossed with plants of breeding line ADV-37, with high oil content and standard fatty acid profile. Oil content and fatty acid composition were measured in individual F₂ seeds and F₂ plants (F₃ seeds averaged). Both F₂ seeds and F₂ plants from the cross ADV-37 × CAS-3 had a significantly higher oil content than those from the reciprocal cross, which indicated the existence of cytoplasmic effects in the genetic control of the trait. A consistent negative correlation between oil content and palmitic acid and a positive correlation between oil content and oleic acid were detected both in F₂ seeds and F₂ plants. Conversely, no consistent correlation between oil content and stearic acid was observed, which suggested the feasibility of simultaneous selection for both traits.     

A new sunflower high oleic mutation confers stable oil grain fatty acid composition across environments

The oil industry demands sunflower oils with high oleic acid content. New varieties producing high oleic oils independently of the growing environment are needed as growers could receive an extra prime for offering them. Oil fatty acid composition of high oleic sunflower hybrids currently available carrying the Pervenets mutation could however be affected by the temperature during the grain filling period. A new high oleic mutation has been obtained to attain oils with ultra-high oleic levels (>90%oleic acid content). This new structural mutation would be able to reduce the variation in oleic acid percentage to changes in the minimum night temperature (MNT). The aim of this work was to assess the response of oil fatty acid composition of the new high oleic mutation to MNT compared to traditional and Pervenets genotypes. Field experiments in different sowing dates and locations and one growth chambers experiment were performed to explore a wide range of temperatures (11.8–23.2 °C) during grain filling. The oleic acid percentage in traditional and high oleic Pervenets genotypes varied between 15.0–50.9% and 87.4–91.2%, respectively, while the new mutation genotype presented values of oleic acid between 91.3 and 92.5%. Moreover, the oleic acid percentage of traditional and Pervenets genotypes showed a linear and positive response to temperature (slopes 2.95 and 0.28%oleic acid °C⁻¹, respectively). No response to temperature was detected in the new mutation genotype. The ultra-high oleic quality from the new high oleic sunflower mutant could be obtained in a wide range of environments as the fatty acid composition was not affected by temperature during grain filling, representing an advantage over the high oleic Pervenets and traditional genotypes.     

Effects of high oleic acid soybean on seed yield,protein and oil contents,and seed germination revealed by near‐isogeneic lines

Typical soybean oil is composed of palmitic, stearic, oleic, linoleic and linolenic acids. High oleic acid content in soybean seed is a key compositional trait that improves oxidative stability and increases oil functionality and shelf life. Using a marker‐assisted selection method, near‐isogenic lines (NILs) of G00‐3213 for the high oleic trait were developed and yield tested. These NILs have various combinations of FAD2‐1A and FAD2‐1B alleles that were derived from the same backcrossing populations. The results indicated that G00‐3213 NILs with both homozygous mutant FAD2‐1A and FAD2‐1B alleles produced an average of 788 g/kg oleic acid content. The results also demonstrated that possessing these mutant alleles did not cause a yield reduction. Furthermore, seed germination tests across 12 temperatures (12.8–32.0°C) showed that modified seed composition for oleic acid in general did not have a major impact on seed germination. However, there was a possible reduction in seed germination vigour when high oleic seeds are planted in cold soil. The mutant FAD2‐1A and FAD2‐1B alleles did not hinder either seed or plant development.     

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.     

向日葵籽仁脂肪和脂肪酸含量近红外光谱模型的建立

为实现向日葵品质的快速无损检测,选取50份具有代表性的油用向日葵材料,采用偏最小二乘法（PLS）构建籽仁脂肪、亚油酸、油酸、硬脂酸和棕榈酸含量的近红外光谱（NIRS）模型。结果表明,脂肪、亚油酸、油酸含量模型校正和验证相关系数均大于0.96,且预测值与化学值相对误差均在10%以下,能够达到样品成分含量的快速测定。硬脂酸和棕榈酸含量模型校正相关系数分别为0.92和0.82,验证相关系数分别为0.83和0.74,预测值与化学值相对误差在4.66%~17.99%之间,可用于样品成分含量的初步预测。本研究构建的NIRS模型,有助于油用向日葵种质资源品质鉴定和快速筛选。     

A mutant of Brassica napus with increased palmitic acid content

An induced mutant from European winter oilseed rape with increased palmitic acid content was phenotypically characterized and genetically analysed. The mutant showed a palmitic acid content of 9.2% compared with 4.5% in the parental cultivar. The oleic acid content decreased from 61.6% to 44.2%, whereas the linoleic and linolenic acid contents increased. The mutant plants grew poorly and their seed oil content was only 31.2% compared with 42.8% in the parental cultivar. The inheritance of the mutant was oligogenic and determined by at least four genes. In the F₂ generation, palmitic acid content was negatively correlated with oil content. This mutant may be useful to improve understanding of the genetic regulation of storage lipid synthesis, but has no immediate value for oilseed rape improvement.     

Fatty Acid Composition of Oil from Erucic Acid-Free Summer Rape Seed (Brassica napus L.) in Relation to Nitrogen Nutrition and Raceme Position

A greenhouse study was conducted to determine the effect of nitrogen supply (30, 100 or 170 ppm N) and raceme position on the fatty acid composition of oil extracted from erucic acid-free summer rape seed ( Brassica napus cv. Callypso ). The seven fatty acids analyzed for include palmitic, palmitolcic, stearic, oleic, linoleic, linolemc, and eicosenoic acids; of which oleic (59.54–64.84 %) and palmitoleic (0.36–0.4 %) acids were the highest and lowest levels respectively. Generally, N nutrition influenced fatty acid pattern only to a little extent. Palmitic, palmitoleic and stearic acid levels were increased by 170 ppm N, depending on raceme position, but oleic and linolenic acids were unaffected. Similarly, 170 ppm N produced the highest fatty acid levels in seeds on the lower portions of racemes, with the exception of oleic acid. This was also true in the case of the upper portions of racemes, except that 30 ppm N produced the highest levels of oleic and linoleic acids in rape seeds. Under the optimum N supply level (i.e. 100 ppm N), position of raceme on the rape plant did not greatly influence the levels of different fatty acids in lipids.     

Opposite oleic acid responses to temperature in oils from the seed and mesocarp of the olive fruit

Olive oil is mostly extracted from the mesocarp (∼95%) of the fruit with the seed (endosperm and embryo, ∼5%) containing little oil. There are correlative and manipulative evidence that temperature modulates fruit oil content and fatty acid composition of the oil from the whole fruit (i.e., with no distinction being made between oils derived from each oil-bearing structure) of olive. Notably, oleic acid concentration of olive oil decreases as fruit mean growth temperature increases. This response in the olive fruit is opposite to that documented in annual oil-seed crops such as sunflower and soybean. The objectives of the present study were: i) to compare temperature effects on fatty acid composition of oil derived from seed and from mesocarp; ii) to compare temperature effects on seed and mesocarp dry weights and oil concentrations. To do this, fruiting branches were enclosed in transparent plastic chambers with individualized temperature control. Temperature was manipulated during the seed growth (Period A) and during the second half of mesocarp growth (Period B) subphases. In both periods, the oleic acid proportion in mesocarp oil decreased as temperature increased, and was accompanied by increases of palmitic acid, linoleic and linolenic acids. Mesocarp dry weight did not respond significantly to temperature, but mesocarp oil concentration fell significantly as temperature increased. Seed dry weight, oil concentration and fatty acid composition exhibited responses to temperature during Period A only, with seed dry weight increasing between 20 and 25 °C with a sharp decrease at higher temperature, and oil concentration linearly falling 1.2% per °C. In contrast, seed oil oleic acid percentage increased between 20 and 28 °C, and fell slightly with higher temperature. Palmitic and stearic acids in seed oil increased sigmoidally with temperature, while linoleic acid decreased sigmoidally. Oleic acid percentage showed opposite responses in oil from the seed and the mesocarp. The response of the seed to temperature was similar to those observed in oil from embryos of annual oil-seed crops, although the abrupt fall in palmitic and stearic acid with temperature >25 °C seems to be distinctive for olive seed oil.     

Genetic analysis of the high oleic acid content in cultivated sunflower (Helianthus annuus L.)

Summary Sunflower lines breeding true for very high oleic acid content in their oil (average levels higher than 85%) were crossed with standard sunflower lines with mean oleic acid levels of 30%. Analysis of the oil of F₁ seeds indicated dominance for high oleic levels and control of the genotype of the embryo. Segregating generations were obtained selfing heterozygous high oleic BC_nF₁ plants from several generations of a backcrossing program to incorporate the high oleic character to standard inbred lines and testcrossing these plants to low oleic material. Analysis of F₂ and testcrossed seeds showed three kind of segregations, in both F₂ and testcrossed populations, with different proportions of low, intermediate and high oleic types. Genetic analysis of these data supported the hypothesis, that the high oleic character is controlled by three dominant complementary genes OL₁, OL₂ and OL₃. Additional data showing F₁ seeds with intermediate oleic content and segregations for high oleic in progenies of intermediate types, suggest the presence of major factors modifying high oleic acid content.     

Inheritance of high oleic acid content in safflower

Safflower (Carthamus tinctorius L.) oil with high oleic acid content (>75%) has a great value for both food and non-food uses. The trait has been reported to be environmentally stable and controlled by recessive alleles at one single gene Ol, even though the influence of modifying genes has been suggested. Additionally, germplasm with higher oleic acid content (>85%) has been reported. The objective of the present research was to study the inheritance of high oleic acid content in genetic sources with both levels of high oleic acid content (>75 and >85%, respectively). A genetic study was conducted by crossing the nuclear male-sterile line CL1 (18% oleic acid) and the high oleic acid lines CR-6 (80%) and CR-9 (87%). The evaluation of the F₁ and F₂ seed generations of the crosses CL1 × CR-6 and CL1 × CR-9 indicated that in both cases the high oleic acid trait was controlled by partially recessive alleles at a single locus. The observation of F₂, F₃, and F₄ segregants with high oleic acid phenotype but lower oleic acid levels than the parents revealed the presence of modifying genes affecting the trait. Crosses between the two high oleic acid lines produced no transgressive segregation other than that caused by the mentioned modifying genes, suggesting that the high oleic acid lines CR-6 and CR-9 share the same alleles at the Ol locus. Differences for oleic acid content between both lines were hypothesized to be produced by the accumulation of genes with a minor effect on the trait.     

In vitro selection for oleic and linoleic acid content in segregating populations of microspore derived embryos of Brassica napus

Microspore derived embryos (MDEs) in Brassica napuscontain large amounts of storage lipids which show a genotype specific fatty acid composition (FAC). One cotyledon of regenerating emblyos can be dissected at an early stage during the in vitro culture and used for fatty acid analysis. Thus, in breeding programmes to modify oil quality, only MDEs having the desired FAC need to be regenerated to plantlets and transferred to the greenhouse. In the present study the applicability of this method for the selection of a high oleic acid content and a low linoleic acid content in the seed oil has been tested by crossing a Brassica napus mutant line having a high oleic acid (C18:1) content in the seed oil (75%) with a wild type doubled haploid line with 62% C18:1 in the seed oil. Microspore culture was applied to the F1 plants. In total 59 MDEs were obtained, from which 31 were cultured with and 28 without 15μM abscisic acid for 3 weeksin vitro. One cotyledon was dissected under aspetic conditions and used for fatty acid analysis. The remaining part of the embryos were further regenerated to plantlets and transferred to the greenhouse to obtain seeds after self pollination. Seeds harvested from the doubled haploid lines in the greenhouse were used for fatty acid analysis and also for growing in the field. The abscisic acid treatment of the MDEs generally improved the correlations for linoleic and oleic acid between the MDEs and the seeds harvested in the greenhouse and the field. The correlations ranged from 0.68** to 0.81**.This indicates that selection for high oleic acid can be started already during an early stage of the in vitro culture. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inheritance of high palmitic acid content in the sunflower mutant CAS-12 and its relationship with high oleic content

CAS‐12 is a sunflower mutant with increased levels of palmitic (C16: 0 = 30%) and oleic (C18: 1 = 55%) acids in its seed oil, hence it has a reduced linoleic acid content (C18: 2 < 5%). This study was conducted to determine the inheritance of high C16: 0 content and its relationship with high C18: 1 content in CAS‐12. Reciprocal crosses involving CAS‐12, CAS‐5 (high C16: 0 content), HAOL‐9 (high C18: 1 content) and HA‐89 (standard fatty acid profile) were made. The F₁, F₂ and BC₁F₁ generations were obtained. The genetic control of the high C16: 0 trait in CAS‐12 was partially recessive and gametophytic. In all cases, this character segregated in the ratio 19: 38: 7 (low: intermediate: high C16: 0 content) in the F₂ generation. These results, together with the lack of segregation for C16: 0 content in crosses between CAS‐12 and CAS‐5, indicated that the genetic control of the high C16: 0 trait in CAS‐12 was similar to that in CAS‐5 in being controlled by partially recessive alleles (p1, p2, and p3) at three loci. Crosses between HA‐89 and CAS‐12, and HAOL‐9 and CAS‐5 (segregating for C16: 0 and C18: 1) demonstrated that the high C16: 0 and the high C18: 1 traits were independently inherited. However, C18: 1 segregation in these crosses exhibited reversal of dominance. Apparently, the low C18: 1 parental lines carried modifier genes causing the deviation.     

Assessment of growth and seed oil composition of kenaf (Hibiscus cannabinus L.) germplasm

This study was conducted to evaluate the growth characteristics and fatty acid composition among 15 kenaf mutants derived from the kenaf germplasm C14 and 15 kenaf accessions originating from Russia, India, China, Iran, and Italy. The overall growth performance (plant height, stem diameter, flowering date, leaf, and flower size) of the stem color mutant lines derived from C14 are similar to those of the original variety. However, the flower color mutant lines derived from C14 showed flowering to occur 10 days later when compared with the original variety and showed smaller leaf sizes than the original variety. Late-ripened kenaf accessions (Jinju, Auxu, and Jnagdae) can yield more bio-mass compared with early or medium-maturing germplasm. The late maturity kenaf (Auxu, Jinju, and Jangdae) has a higher oil percentage than the early maturity germplasm. Linoleic, oleic, and palmitic acids were the predominant fatty acids in all kenaf seeds. The stem color mutant lines significantly surpassed the parental means of all saturated fatty acids. In addition, the flower color mutant lines showed broad ranges of variation in oleic acid. The 15 accessions showed a wide range of fatty acid compositions, spanning from 29.75 to 38.30% saturated fatty acids and 61.70 to 70.24% total unsaturated fatty acids, and the late maturity kenaf has a higher linoleic acid percentage than the early maturity germplasm. The flowering period was highly positively (P ≤ 0.01) correlated with the plant height, stem diameter, oil percent, and linolenic acid (C_18:3), and it was significantly negatively (P ≤ 0.01) correlated with stearic acid (C_18:0). These results will provide valuable information to assist the parental selection of kenaf breeding.     

Genetic structure composed of additive QTL,epistatic QTL pairs and collective unmapped minor QTL conferring oil content and fatty acid components of soybeans

The relative importance of various types of quantitative trait locus (QTL) conferring oil content and its fatty acid components in soybean seeds was assessed through testing a recombinant inbred line (RIL) population (derived from KF1 × NN1138-2) in randomized blocks experiments in 2004–2006. The contents of oil and oleic, linoleic, linolenic, palmitic and stearic acids were determined with automatic Soxhlet extraction system and gas chromatography, respectively. Based on the established genetic linkage map with 834 markers, QTLNetwork2.0 was used to detect QTL under the genetic model composed of additive, additive × additive (epistasis), additive × year and epistasis × year effects. The contributions to the phenotypic variances of additive QTL and epistatic QTL pairs were 15.7% (3 QTL) and 10.8% (2 pairs) for oil content, 10.4% (3 QTL) and 10.3% (3 pairs) for oleic acid, 11.6% (3 QTL) and 8.5% (2 pairs) for linoleic acid, 28.5% (7 QTL) and 7.6% (3 pairs) for linolenic acid, 27.0% (6 QTL) and 16.6% (7 pairs) for palmitic acid and 29.7% (5 QTL) and 4.3% (1 pair) for stearic acid, respectively. Those of additive QTL by year interaction were small and no epistatic QTL pair by year interaction was found. Among the 27 additive QTL and 36 epistatic QTL (18 pairs), three are duplicated between the two QTL types. A large difference was found between the genotypic variance among RILs and the total variance of mapped QTL, which accounted for 52.9–74.8% of the genotypic variation, much larger than those of additive QTL and epistatic QTL pairs. This part of variance was recognized as that due to a collection of unmapped minor QTL, like polygenes in biometrical genetics, and was designated as collective unmapped minor QTL. The results challenge the breeders for how to pyramid different types of QTL. In addition, the present study supports the mapping strategy of a full model scanning followed by verification with other procedures corresponding to the first results.     

EMS-induced mutation of an endoplasmic reticulum oleate desaturase gene (<Emphasis Type="Italic">FAD2</Emphasis>-<Emphasis Type="Italic">2</Emphasis>) results in elevated oleic acid content in rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

The development of rapeseed cultivars (Brassica napus L.) with high oleic acid and low linolenic acid is highly desirable for food and industrial applications. In this study, the Korean rapeseed cultivar Tamla was used for ethyl methanesulfonate (EMS)-induced mutagenesis and seed oils were screened up to generation M₇ for high oleate mutants. Two mutant populations (M₇) with an average of approximately 76% oleic acid content were isolated. Yield components between two mutant populations and untreated Tamla plants were not substantially different, although the mutants in the vegetative stage were slightly smaller in size than Tamla. Genomic analyses of six fatty acid desaturase (four FAD2 and two FAD6) genes revealed that the elevated oleic acid content in the mutants is the result of single gene mutations. Changes in DNA sequence were observed in two genes out of six fatty acid desaturase (four FAD2 and two FAD6). FAD2-2 exhibited a 2-bp deletion in the upstream region of the gene in the two mutants, resulting in a severely truncated polypeptide (57 aa instead of 469 aa), while six point mutations in the other gene did not result in changes in the amino acid sequence. Based on these results, FAD2-2, an endoplasmic reticulum (ER) oleic acid desaturase, is affected in the mutants, resulting in a ~ 7% increase in oleic acid content in comparison to untreated Tamla plants. The induced mutants could be utilized for the development of high oleic oil rapeseed varieties and for regulatory studies of lipid metabolism in seed oils.     

The effect of cold and heat treatments on the anther culture response of diverse rye genotypes

The reduction of saturated fats in canola oil has recently been promoted as a goal for breeders for commercial and human health benefits. Currently, saturated fatty acids in Canadian produced canola oil are above the 7% level, and the objective of this study was to generate canola lines with reduced major saturates (palmitic and stearic), by several percent. Mutant embryos generated from direct ultraviolet radiation mutagenesis of microspores in vitro were subjected to heat during the maturation stage. Heat artificially elevated the saturate levels in developing mutant embryos, allowing efficient identification of those with reduced saturates within the expanded range using HPLC fatty acid analysis of the embryo cotyledons. Mutagenesis produced embryos with fatty acids altered in both directions. Major saturate levels in the cotyledons of heat-treated mutant embryos ranged from 3.3 to 16.4% (heated control ca. 6–9%) and 1.3–10% (heated control ca. 2–4%) for palmitic and stearic fatty acids, respectively. Doubled haploid seed derived from embryos grown at normal temperatures confirmed the reduction of major saturates. HPLC fatty acid analysis of DH seed identified saturate levels ranging from 3.9 to 6.5% (control ca. 5.5%) and 0.9–2.7% (control ca. 1.7%) for palmitic and stearic fatty acids, respectively. Various doubled haploids were identified with major saturate levels below 5.5%. Concomitant positive changes in the unsaturated fatty acids (18:1, 18:2, 18:3) among the mutant lines are also discussed.     

油葵HaDGAT2基因的功能及表达特性分析

二酰甘油酰基转移酶(DGAT)在植物油脂合成中起关键作用,其活性高低与植物含油量显著相关。为探明油葵二酰甘油酰基转移酶2基因(HaDGAT2)的功能,本研究以‘新葵杂5号’为试验材料,从油葵中扩增HaDGAT2基因序列并构建酵母穿梭表达载体pYES2-Ha DGAT2,将重组载体转入酿酒酵母INVSc1后提取酵母总脂肪酸,甲酯化后GC-MS分析。结果显示,在酿酒酵母中可成功诱导HaDGAT2基因,且转HaDGAT2基因酵母中棕榈油酸(16:1)和油酸(18:1)含量与对照相比得到提高。结果表明,HaDGAT2基因在调控油脂合成的过程中具有重要作用。实时荧光定量PCR分析结果表明HaDGAT2基因在油葵根、茎、叶、花、子叶和不同发育时期的种子中都有表达,且在开花后31天的种子中表达量高,说明该基因表达无组织特异性,在油葵种子油脂积累后期起关键调控作用。本研究为深入了解油葵油脂和调控机制提供了基础,为今后利用分子育种手段提高并改良葵花籽油的品质提供了理论基础。     

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.     

Effect of maturity and temperature on breeding for mid-oleic soybean lines under the high heat conditions of the Mississippi Delta,USA

Soybean (Glycine max (L) Merr.) seed is an important source of oil for human consumption. Increasing the percentage of oleic acid in soybean seed oil is an important breeding objective because increasing the oleic acid content improves the oxidative stability of the oil. Extensive literature shows that temperature during seed-fill is positively correlated with the content of oleic acid in soybeans. In addition, it was shown that a maturity QTL was linked to an oleic acid QTL. The Mississippi Delta in the USA is a hot environment where soybean harvest begins in August, which is the hottest part of the season. The purpose of this research was to determine the possibility of developing both early- and late-maturing lines with consistent >?50% oleic acid content in Mississippi. We selected early and late segregants from three genetically different breeding populations also segregating for mid-oleic acid derived from crosses to germplasm N98-4445A, a non-transgenic freely available line with >?50% oleic acid. The selected lines were grown in 2 years in three trials at Stoneville, MS. Results indicated that no late-maturing lines (MG V) met the targeted mid-oleic acid level, whereas MG III and early MG IV lines with oleic acid over 50% were obtained. No maturity-alone effect on oleic acid content was observed, due to the bias of the strong negative correlation between maturity date and mean temperature during seed-fill. This study demonstrated that breeders can effectively develop early soybeans with oleic acid levels greater than 50% for the midsouthern USA.