High Seed Oil Content Research Articles

Research and Development of Natural Vegetable Insulating Oil Based on Jatropha curcas Seed Oil

Jatropha curcas is a natural non-food resource with high oil-content seeds, that has attracted worldwide attention as it is an ideal renewable resource for the production of biofuels. With the increasing use of vegetable insulating oil in related industries, it is valuable to develop the vegetable insulating oils from Jatropha curcas seed oil. This study explores how to use Jatropha curcas seed oil to prepare high-quality natural vegetable insulating oil. A six-step process is first established according to the optimization results of alkali refining, activated clay treatment and alumina treatment of Jatropha curcas seed oil, combined with cold treatment, water washing and high temperature decompression treatment. Physicochemical and electrical performance tests show that most of the properties of the prepared vegetable insulating oil are significantly improved compared with the original seed oil, and meet the standard requirements for vegetable insulating oil, especially with no sulfur corrosion, a breakdown voltage of 72 kV and an acid value (KOH, potassium hydroxide) of 0.012 mg/g.

Fertility variation among Paeonia lactiflora genotypes and fatty acid composition of seed oil

Herbaceous peony (Paeonia lactiflora Pall.) is a prospective oilseed crop and is widely cultivated in temperate regions. In the present study, eleven fertility characteristics of sixteen peony genotypes were systematically investigated through two consecutive years of observation, and correlation analysis between the parameter seed yield per stem and other ten parameters was performed. Then the fatty acid composition in the seed oil was further determined with six peony cultivars selected from the investigation. The results showed that the examined sixteen genotypes exhibited a wide range of significant differences in fertility traits. A significant positive correlation was observed between seed yield and other seven parameters (P < 0.01). And the parameter follicle symmetry (r = 0.570**) was further established as an indicative parameter in the early selection of high-yield peony genotypes. Further determination revealed that the average oil content of peony seeds was 32.71 %. Total ten fatty acids (FAs) were detected in peony seed oil and the unsaturated fatty acids (UFAs) accounted for 94.38–95.09 %. Oleic acid (OA), linoleic acid (LA) and linolenic acid (ALA) were three principal UFAs. The contents of these UFAs varied with genotype, but were overall more balanced than those in other seed oil. ‘Hangshao’ and ‘Fenghuang Niepan’ were eventually recommended for oilseed usage due to their considerable seed yields (30.75 g and 25.63 g per stem, respectively) and high seed oil content (33.34 % and 32.56 %, respectively). These findings would provide helpful references for the selection of oleaginous peony cultivars and accelerate the development of oil peony industry.

Techno-economic analysis of pennycress production, harvest and post-harvest logistics for renewable jet fuel

Pennycress (Thlaspi arvense L.) is a winter annual oilseed crop with relatively high seed oil content (25-36%-wet basis), which can be planted as cover crop in corn-soybean rotation in the Midwestern U.S., to provide both economic benefits and ecosystem services. Pennycress oil has adequate quality for conversion to renewable jet fuel (RJF); however, the technical feasibility and cost of pennycress supply at the commercial scale have not been evaluated; so, the objective of this study was to evaluate techno-economics of the production, harvest and post-harvest logistics of pennycress as an RJF feedstock. In addition, an uncertainty analysis was performed to address the inherent variability of the parameters used for this evaluation. This study considered the feedstock supply for a biorefinery with RJF production capacity of around 19 million liters per year (i.e., 5 million gallons per year) in Ohio. Technical feasibility included the assessment of resources (land, infrastructure, machineries, fuel, labor, and consumables) for the production (i.e., planting, fertilizer and pesticide applications), harvest and post-harvest logistics (i.e., grain handling, transportation, drying and storage). Economic analyses included estimation of pennycress production and logistics costs. Annual pennycress seed requirement for the selected biorefinery capacity was estimated to be 90–115 thousand t (90% central range - CR), which would require pennycress plantation in 41–63 thousand ha (90% CR) land in corn-soybean rotation. The direct fossil fuel use ratio (i.e., fossil fuel use per liter of RJF produced) for pennycress production and logistics was estimated to be 0.06–0.09 L/L (90% CR). Estimated total cost for the production and logistics was 170–230 $/t (90% CR); and it was identified to be highly sensitive to pennycress seed yield. The outcomes of this research contribute to identifying the bottlenecks and hotspots for establishment of pennycress at the commercial scale in corn-soybean rotation in Ohio and Midwestern U.S.

Comparative Evaluation of Economically Valuable Traits in New Sunflower Hybrids of IOC Selection

Comparative Evaluation of Economically Valuable Traits in New Sunflower Hybrids of IOC Selection

Nutritional value of Sesamum indicum L. was improved by Azospirillum and Azotobacter under low input of NP fertilizers

BackgroundSesame (Sesame indicum L.) is well-known as a versatile industrial crop having various usages and contains 50–55% oil, 20% protein, 14–20% carbohydrate and 2–3% fiber. Several environmental factors are known to adversely affect yield and productivity of sesame. Our overall aim was to improve the growth, yield and quality of sesame cv. TS-3 using plant growth promoting rhizobacteria (PGPR) and saving the nitrogen and phosphate fertilizers (NP) by 50%. Field experiment (randomized complete block design) was conducted during the months of July to October of two consecutive years 2012–2013. Azospirillum (AL) and Azotobacter (AV) were applied as seed inoculation alone as well as along with half of the recommended dose of nitrogen (N) and phosphate (P) fertilizers (urea and diammonium phosphate) at the rate of 25 kg/ha and 30 kg/ha respectively.ResultsHere we report that A. lipoferum along with half dose of NP fertilizers (ALCF) were highly effective in increasing the agronomic and yield traits of sesame as compared to the control. A. vinelandii plus NP fertilizers (AVCF) exhibited higher seed oil content. Minimum acid value, optimum specific gravity and modified fatty acid composition were observed in ALCF treatment. Increase in oleic acid by ALCF is directly linked with improved oil quality for health benefits as oleic acid is the fatty acid which creates a balance between saturation and unsaturation of oil and for the hypotensive (blood pressure reducing) effects.ConclusionIt is inferred that ALCF treatment improved plant growth, seed yield and oil quality of sesame pertaining to good quality edible oil production.

Potential of the C Genome of Different Variants of Brassica oleracea for the Improvement of Agronomic and Seed Quality Traits of B. napus Canola

ABSTRACTThe narrow genetic base of Brassica napus L. canola, especially of its C genome, is an impediment for continued improvement of this crop. We investigated the gene pools of different variants of B. oleracea L. to improve agronomic and seed quality traits of B. napus canola. For this, B. napus canola inbred populations were developed from six interspecific crosses, involving a single B. napus canola line and six accessions of B. oleracea belonging to four variants of this species, following two breeding techniques (F2– and BC1–derived lines). Among these, the population derived from crossing with var. italica gave the greatest seed yield and also had shorter duration of flowering than most of the other populations. The population developed using var. botrytis had the highest seed oil content, and seed yield was comparable with the population developed using var. italica. Populations based on var. capitata had the lowest oil but greater protein content than most of the populations. Several lines from these interspecific crosses exceeded seed yield of the B. napus parent and also had acceptable agronomic and seed quality traits. Comparing the two breeding techniques, the F2–derived population gave greater yield than the BC1–derived population, whereas the BC1–derived population flowered and matured earlier than the F2–derived population. Genetic distance of the inbred lines from the B. napus parent showed positive correlation of r ≥ 0.4 with days to flowering and seed protein content and negative correlation with seed oil content, whereas correlation with seed yield was negative and weak (r = −0.18). Thus, the results showed that the B. oleracea gene pool, especially var. italica and botrytis, can be used to improve spring B. napus canola, as well as to broaden the genetic base of this crop.

Valorisation of hemp inflorescence after seed harvest: Cultivation site and harvest time influence agronomic characteristics and essential oil yield and composition

Cannabis sativa L. is a multipurpose crop, whose industrial varieties, complying with the 0.2% Δ9-tetrahydrocannabinol (THC) threshold set by the EU legislation, can be cultivated without restrictions by farmers. Other than its traditional use as a source of bast fibres from the stems, the fixed oil extracted from its seeds represents a valuable nutritional product. Its inflorescence is also a further exploitable threshing residue originating from seed harvest, as they can be used for the extraction of the essential oil (EO), a high-value added product.This study aims at contributing to the re-evaluation of industrial hemp cultivation as an agro-environmentally sustainable crop for the diversification of Mediterranean cropping systems, by exploring the possibility of recovering the EO from the inflorescence after seed harvest.The influence of the cultivation site (lowland and upland of Pisa province, Tuscany, central Italy) and the harvest time (August and September) have been investigated on the ‘Fedora 17’ monoecious hemp cultivar: the main agronomic traits in term of stem, seed and inflorescence production, as well as essential oil yield and composition have been evaluated.The crops harvested in September exhibited higher total dry yield as well as higher inflorescence and stem yields, while neither the site nor the harvesting period influenced the seed production, which was significantly influenced by harvest time x cultivation site interaction. Both seed fixed oil and crude protein content were affected by the cultivation site only, but in the opposite sense: the highest seed oil content was reached in the upland area, while the plants grown in the plain area exhibited the largest seed protein content. All the extracted EOs were rich in sesquiterpenes (mostly β-caryophyllene and its oxidized derivatives, and α-humulene), but monoterpene hydrocarbons were significantly represented as well (mainly α- and β-pinene, and myrcene). The EOs extraction yields were slightly higher in the earlier harvest for both sites.

Principal Component Analysis for Identification of Superior Castor Bean Hybrids

The identification of superior genotypes in plant breeding programs is not a quick and simple task and requires breeders to become aware of more suitable and efficient tools for evaluating crop performance. Univariate analyses are often too narrow for the scope of plant breeding because it lacks consideration of relations between variables. Therefore, the objective of this study was to select castor bean hybrids based on principal component analysis (PCA). Trials were conducted in 2017 with 31 hybrids in a randomized block design with 4 replications. The following variables were used to evaluate crop performance: plant height (PH), insertion height of the primary raceme (HPR), number of stem nodes (NN), number of racemes (NR), number of seeds (NS), stem diameter (SD), number of fruits (NF), 100-seed weight (S100) and seed oil content (SOC). The first three principal components (PCs) explained approximately 75.01 % of all the variability in the dataset. PC 1, 2 and 3 were particularly related to productivity (NS, NR, S100 and NF), plant size (SD, HPR and PH) and oil production (SOC), respectively. Hybrids 14 and 23 were the most suitable for grain production in commercial scale due to short-height, which favors mechanical harvesting. Commercial hybrid 26 showed high SOC, medium grain yield and medium-height.

Genetic Diversity and Population Structure of a Camelina sativa Spring Panel.

There is a need to explore renewable alternatives (e.g., biofuels) that can produce energy sources to help reduce the reliance on fossil oils. In addition, the consumption of fossil oils adversely affects the environment and human health via the generation of waste water, greenhouse gases, and waste solids. Camelina sativa, originated from southeastern Europe and southwestern Asia, is being re-embraced as an industrial oilseed crop due to its high seed oil content (36–47%) and high unsaturated fatty acid composition (>90%), which are suitable for jet fuel, biodiesel, high-value lubricants and animal feed. C. sativa’s agronomic advantages include short time to maturation, low water and nutrient requirements, adaptability to adverse environmental conditions and resistance to common pests and pathogens. These characteristics make it an ideal crop for sustainable agricultural systems and regions of marginal land. However, the lack of genetic and genomic resources has slowed the enhancement of this emerging oilseed crop and exploration of its full agronomic and breeding potential. Here, a core of 213 spring C. sativa accessions was collected and genotyped. The genotypic data was used to characterize genetic diversity and population structure to infer how natural selection and plant breeding may have affected the formation and differentiation within the C. sativa natural populations, and how the genetic diversity of this species can be used in future breeding efforts. A total of 6,192 high-quality single nucleotide polymorphisms (SNPs) were identified using genotyping-by-sequencing (GBS) technology. The average polymorphism information content (PIC) value of 0.29 indicate moderate genetic diversity for the C. sativa spring panel evaluated in this report. Population structure and principal coordinates analyses (PCoA) based on SNPs revealed two distinct subpopulations. Sub-population 1 (POP1) contains accessions that mainly originated from Germany while the majority of POP2 accessions (>75%) were collected from Eastern Europe. Analysis of molecular variance (AMOVA) identified 4% variance among and 96% variance within subpopulations, indicating a high gene exchange (or low genetic differentiation) between the two subpopulations. These findings provide important information for future allele/gene identification using genome-wide association studies (GWAS) and marker-assisted selection (MAS) to enhance genetic gain in C. sativa breeding programs.

Effect of breeding on nitrogen use efficiency-associated traits in oilseed rape.

Oilseed rape is one of the most important dicotyledonous field crops in the world, where it plays a key role in productive cereal crop rotations. However, its production requires high nitrogen fertilization and its nitrogen footprint exceeds that of most other globally important crops. Hence, increased nitrogen use efficiency (NUE) in this crop is of high priority for sustainable agriculture. We report a comprehensive study of macrophysiological characteristics associated with breeding progress, conducted under contrasting nitrogen fertilization levels in a large panel of elite oilseed rape varieties representing breeding progress over the past 20 years. The results indicate that increased plant biomass at flowering, along with increases in primary yield components, have increased NUE in modern varieties. Nitrogen uptake efficiency has improved through breeding, particularly at high nitrogen. Despite low heritability, the number of seeds per silique is associated positively with increased yield in modern varieties. Seed weight remains unaffected by breeding progress; however, recent selection for high seed oil content and for high seed yields appears to have promoted a negative correlation (r= -0.39 at high and r= -0.49 at low nitrogen) between seed weight and seed oil concentration. Overall, our results reveal valuable breeding targets to improve NUE in oilseed rape.

Study on the combining ability and gene action in sunflower through line × tester mating design

This study was conducted to evaluate gene action and combining ability for yield, agronomic traits through line X tester analysis with 36 hybrids, developed from nine testers and four lines. The experiment was conducted in randomized complete block design with three replicates for two years 2015-16 and 2016-17 at AICRP-Sunflower, Nimpith Centre. Gene action and combining ability for seed yield and other yield attributing agronomic traits were studied in the sunflower hybrids. The cytoplasmic male sterile lines were used as female lines while some new male inbreds were introduced as testers in the form of fertility restorers. The inbred lines and their F1hybrids differed significantly in their mean values of the traits under the present study. For each of the traits, highly significant positive and negative GCA values were recorded which was reflected from the hybrid combinations. Highly significant positive effects of the GCA for seed oil content were observed in the Rf-lines R-138-2, R-104 and EC-601978 and in Pet-89-1A. On the basis of analysis, SCA: GCA ratio variances indicated that the most of the total genetic variation for head diameter, oil content (%), seed yield per plant or seed yield in kg per hectare, volume weight (g/100 cc), 100 seed weight(g), 100 seed kernel weight, hull content and oil yield in kg per hectare were governed by the non-additive gene action or non-additive component of genetic variance had a more significant role in the inheritance of the above mentioned traits in the F1 hybrid combinations in sunflower. The study’s results indicate that the additive as well as non-additive components had a more or less equal role for the inheritance of plant height trait in sunflower. Highly significant positive effects of the GCA for seed yield (kg/ha) were observed in the Rf-lines R-12-96, R-104, EC-601978 and R-630 and in Pet-2-7-1A and CMS-107A. For early maturity and semi-dwarfness, the best general combiners were CMS P-2-7-1A and CMS-10A and EC-601958 (restorer line). Five parents, R-104, R-12-96, EC-601978, EC-601958 and P-2-7-1A exhibited positive high gca effect for seed yield and some other yield components like head diameter, 100 seed weight, volume weight (g/100cc) and oil %, therefore, these five parents could be adjudged good general combiners for high seed oil content as well as the high oil yielder sunflower hybrids in near future. It also depicted that the above genotypes appeared to possess high concentration of non-additive genes for seed yield and component traits. The results of this study may be used for the identification of new high yielding sunflower hybrids based on the hybridization between the best combiners.

Insight into the evolution and functional characteristics of the pan-genome assembly from sesame landraces and modern cultivars.

SummarySesame (Sesamum indicum L.) is an important oil crop renowned for its high oil content and quality. Recently, genome assemblies for five sesame varieties including two landraces (S. indicum cv. Baizhima and Mishuozhima) and three modern cultivars (S. indicum var. Zhongzhi13, Yuzhi11 and Swetha), have become available providing a rich resource for comparative genomic analyses and gene discovery. Here, we employed a reference‐assisted assembly approach to improve the draft assemblies of four of the sesame varieties. We then constructed a sesame pan‐genome of 554.05 Mb. The pan‐genome contained 26 472 orthologous gene clusters; 15 409 (58.21%) of them were core (present across all five sesame genomes), whereas the remaining 41.79% (11 063) clusters and the 15 890 variety‐specific genes were dispensable. Comparisons between varieties suggest that modern cultivars from China and India display significant genomic variation. The gene families unique to the sesame modern cultivars contain genes mainly related to yield and quality, while those unique to the landraces contain genes involved in environmental adaptation. Comparative evolutionary analysis indicates that several genes involved in plant‐pathogen interaction and lipid metabolism are under positive selection, which may be associated with sesame environmental adaption and selection for high seed oil content. This study of the sesame pan‐genome provides insights into the evolution and genomic characteristics of this important oilseed and constitutes a resource for further sesame crop improvement.

Production of omega 3-rich oils from underutilized chia seeds. Comparison between supercritical fluid and pressurized liquid extraction methods

Chia seeds constitute a promising source of α-linolenic acid (ALA). In the present work, an underutilized and cheaper set of chia seeds, which were discarded after the harvest according to quality criteria - named in this work as low oil content seeds (LOCS) - have been evaluated as a potential source for obtaining PUFA-enriched oils against the commonly studied high-quality chia seeds denoted as high oil content seeds (HOCS) in this study. Two efficient and environmental friendly techniques, supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE), were evaluated to optimize the extraction process of chia oil. At 60 °C, by using pressurized food-grade ethanol, recoveries close to 100% were achieved from both sets of seeds in a short extraction time (10 min). By using SFE, the greatest oil extraction yield (>95%) was attained at the highest pressure and temperature conditions (45 MPa and 60 °C) after 240 min. At the early stage of SFE extraction, both LOCS and HOCS exhibited a similar kinetic behavior, reaching oil extraction rates of 0.59 g oil/min and 0.64 g oil/min, respectively. No differences were found between the fatty acid profile of the oils extracted from LOCS and HOCS both by PLE and SFE. ALA and linoleic acid (LA) concentrations ranged between 65‐68% and 17–23% respectively, and a predominance of high molecular weight triglycerides (≥ CN50), was found in all extracted oils. In conclusion, LOCS might constitute a new suitable raw material for the production of ALA-enriched oils. Concerning the extraction methods assayed, the oil was almost entirely recovered by both PLE and SFE at the used conditions.

Molecular mechanism of the extended oil accumulation phase contributing to the high seed oil content for the genotype of tung tree (Vernicia fordii)

BackgroundOil from seeds of the tung tree (Vernicia fordii) has unique drying properties that are industrially important. We found that the extended oil accumulation period was related to the high seed oil content at maturity among tung tree population. In order to understand the molecular mechanism underlying the high oil content in tung tree seed, Tree H and L were adopted for the further investigation, with seed oil content of about 70 and 45%, respectively. We compared the transcriptomic changes of seed at various times during oil accumulation between the two trees.ResultsTranscriptomes analysis revealed that many genes involved in glycolysis, fatty acid synthesis, and tri-acyl glyceride assembly still kept high expression in the late period of seed oil accumulation for Tree H only. Many genes in fatty acid degradation pathway were largely up regulated in the late period of seed oil accumulation for Tree L only. Four transcription factors related to fatty acid biosynthesis had different expression pattern in the seed oil accumulation period for the two trees. WRI1 was down regulated and kept the low expression in the late period of seed oil accumulation for the two trees. PII, LEC1 and LEC1-LIKE extended the high expression in the late period of seed oil accumulation in Tree H only.ConclusionsThe continued accumulation of oil in the late period of seed oil accumulation for Tree H was associated with relatively high expression of the relevant genes in glycolysis, fatty acid synthesis and tri-acyl glyceride assembly. PII, LEC1, and LEC1-LIKE rather than WRI1 should play an important role in the oil continual accumulation in the late period of seed oil accumulation in Tree H. This study provides novel insight into the variation in seed oil content and informs plant breeding strategies to maximize oil yield.

Genome sequence of Jatropha curcas L., a non-edible biodiesel plant, provides a resource to improve seed-related traits.

Summary Jatropha curcas (physic nut), a non‐edible oilseed crop, represents one of the most promising alternative energy sources due to its high seed oil content, rapid growth and adaptability to various environments. We report ~339 Mbp draft whole genome sequence of J. curcas var. Chai Nat using both the PacBio and Illumina sequencing platforms. We identified and categorized differentially expressed genes related to biosynthesis of lipid and toxic compound among four stages of seed development. Triacylglycerol (TAG), the major component of seed storage oil, is mainly synthesized by phospholipid:diacylglycerol acyltransferase in Jatropha, and continuous high expression of homologs of oleosin over seed development contributes to accumulation of high level of oil in kernels by preventing the breakdown of TAG. A physical cluster of genes for diterpenoid biosynthetic enzymes, including casbene synthases highly responsible for a toxic compound, phorbol ester, in seed cake, was syntenically highly conserved between Jatropha and castor bean. Transcriptomic analysis of female and male flowers revealed the up‐regulation of a dozen family of TFs in female flower. Additionally, we constructed a robust species tree enabling estimation of divergence times among nine Jatropha species and five commercial crops in Malpighiales order. Our results will help researchers and breeders increase energy efficiency of this important oil seed crop by improving yield and oil content, and eliminating toxic compound in seed cake for animal feed.

Seed Oil Accumulation and Yield of Safflower Affected by Water Supply and Harvest Time

Core Ideas Deficit irrigation conditions decreased safflower seed and oil yield.Safflower cultivars demonstrated different reactions drought stress.Sina and Faraman cultivars had higher seed oil content across all irrigation treatments.Highest oil yield across all irrigation treatments was produced by Sina cultivarHarvest time deferment was associated with increased oil oxidation in all cultivars. Drought stress significantly declines crop yield. Efficient soil moisture management and its consequent effects on metabolic changes which happen in response to drought stress are important in dry regions agriculture. This research was performed to evaluate yield, yield components, and oil accumulation in safflower (Carthamus tinctorius L.) cultivars seed in response to water deficit conditions. A field experiment was conducted at the Research Farm of the College of Agriculture, Tabriz University during two growing seasons of 2014 and 2015. The treatments were arranged as split plots based on randomized complete block design with three replicates. Irrigation treatments (irrigation after 70, 100, 130, and 160 mm evaporation from class A pan) were assigned to the main plots and spring safflower cultivars (Faraman, Goldasht, Sina, and Soffeh) were allocated to the subplots. Safflower seeds were harvested in 5‐d intervals at seven stages during development and maturity period. The result showed that Sina cultivar had the highest seed yield per unit area. Maximum oil percentage of safflower seeds was obtained at 1 to 12 d after plant physiological maturity. Water stress caused seed oil percentage decline across all cultivars. Sina and Faraman cultivars had higher oil percentage across all irrigation treatments. The highest oil and seed yield per unit area under both full and limited irrigation conditions was produced by Sina cultivar. Drought stress decreased seed yield, yield components, and oil content across all safflower cultivars, however, the extent of the damage was limited due to cultivar genetic characteristics and ecological origin.

Intraspecific and interspecific adaptive latitudinal cline in Brassicaceae seed oil traits.

Nearly all seed plants rely on stored seed reserves before photosynthesis can commence. Natural selection for seed oil traits must have occurred over 319 million years of evolution since the first seed plant ancestor. Accounting for the biogeographic distribution of seed oil traits is fundamental to understanding the mechanisms of adaptive evolution in seed plants. However, the evolution of seed oils is poorly understood. We provide evidence of the adaptive nature of seed oil traits at the intraspecific and interspecific levels in Brassicaceae-an oilseed-rich and economically important plant family. Univariate statistics, Pearson's correlation, multiple regression, generalized linear mixed model analysis, and phylogenetic autocorrelation tests on seed oil traits of 360 accessions of Arabidopsis thaliana and 216 Brassicaceae species helped provide evidence of the adaptive nature of seed oil traits. At higher latitudes, both seed oil content and unsaturated fatty acids have selective advantages in Arabidopsis thaliana (intraspecific-level), while only unsaturated fatty acids have selective advantages across 216 Brassicaceae species (interspecific-level). The seed oil patterns fit within the theoretical framework of the gradient model. Seed oil content increases significantly from temperate to subtropical to tropical regions in Brassicaceae herbs. Absence of phylogenetic signals for seed oil traits and high seed oil content in four tribes of Brassicaceae were observed. Multiple seed oil traits are adaptive in nature and follow a gradient model. Consistent evolutionary patterns of seed oil traits were observed at the intraspecific and interspecific levels in Brassicaceae. Seed oil traits change with latitude and across biomes, suggesting selection. The absence of a phylogenetic signal for seed oil traits and the occurrence of high seed oil content in four Brassicaceae tribes provides evidence of the adaptive nature of seed oil traits in Brassicaceae.

Engineering Camelina sativa (L.) Crantz for enhanced oil and seed yields by combining diacylglycerol acyltransferase1 and glycerol-3-phosphate dehydrogenase expression.

SummaryPlant seed oil‐based liquid transportation fuels (i.e., biodiesel and green diesel) have tremendous potential as environmentally, economically and technologically feasible alternatives to petroleum‐derived fuels. Due to their nutritional and industrial importance, one of the major objectives is to increase the seed yield and oil production of oilseed crops via biotechnological approaches. Camelina sativa, an emerging oilseed crop, has been proposed as an ideal crop for biodiesel and bioproduct applications. Further increase in seed oil yield by increasing the flux of carbon from increased photosynthesis into triacylglycerol (TAG) synthesis will make this crop more profitable. To increase the oil yield, we engineered Camelina by co‐expressing the Arabidopsis thaliana (L.) Heynh. diacylglycerol acyltransferase1 (DGAT1) and a yeast cytosolic glycerol‐3‐phosphate dehydrogenase (GPD1) genes under the control of seed‐specific promoters. Plants co‐expressing DGAT1 and GPD1 exhibited up to 13% higher seed oil content and up to 52% increase in seed mass compared to wild‐type plants. Further, DGAT1‐ and GDP1‐co‐expressing lines showed significantly higher seed and oil yields on a dry weight basis than the wild‐type controls or plants expressing DGAT1 and GPD1 alone. The oil harvest index (g oil per g total dry matter) for DGTA1‐ and GPD1‐co‐expressing lines was almost twofold higher as compared to wild type and the lines expressing DGAT1 and GPD1 alone. Therefore, combining the overexpression of TAG biosynthetic genes, DGAT1 and GPD1, appears to be a positive strategy to achieve a synergistic effect on the flux through the TAG synthesis pathway, and thereby further increase the oil yield.

Determinants of yield and quality in winter rapeseed (Brassica napus L.) under Mediterranean conditions

SUMMARYWinter rapeseed was introduced into Greece a decade ago to provide oil for biodiesel. To identify agronomic traits affecting yield and quality, three hybrids and an inbred line were tested over two seasons (2005–2006 and 2006–2007) and four locations, in central and northern Greece, varying in pedo-climatic conditions. The large variations in seed yield, quality and agronomic traits were largely ascribed to location; in contrast, cultivar accounted for ⩽0·010 of the variation for many traits. Below 40°N, rapeseed is a risky crop; short season, high temperatures and low rainfall during reproductive growth diminished seed yield and oil content, increased oleic and erucic acid and minimized linolenic acid. A hybrid, Exact, with tall stature and large seeds was adaptive to such conditions. The most productive location had dense stands with tall plants bearing numerous pods on the main raceme. At the site with the coldest winter, plant density (PD) was lowest (ca. 30 plants/m2) but rapeseed compensated by producing large seeds, with high oil content and harvest index (HI). A biplot revealed that the hybrid Excalibur, outperforming the other cultivars for oil content in six out of eight trials, produced the highest and most stable oil yield. Combined data showed that seed yield and oil yield were positively correlated with PD, seed size and HI and negatively to the number of pods on branches and per plant. Large seeds had high seed oil content. Oleic acid was negatively correlated to linolenic acid concentration. High temperatures and low rainfall favoured oleic acid, which was positively associated with seed number per pod.

A high-Oil castor cultivar developed through recurrent selection

Castor bean (Ricinus communis L.) seed oil has unique characteristics and can be used as feedstock for many biobased products. Under greenhouse conditions, a previous recurrent selection for high-oil castor seeds from a base population resulted in a new population with an increased mean oil content from 50.33 to 54.47% dry weight, average single seed weight from 0.44 to 0.54g, and correlation between oil content and weight from moderate (r=0.43, p<0.0001) to strong (r=0.77, p<0.0001). Here, we describe field trials to evaluate the oil content and seed weight of the new (Test), and base (Control) populations. Duplicated Tests and Controls were planted and the trials were repeated for two consecutive years. From planting to seed harvesting, no difference in growth pattern was observed in either of the populations. Test seeds had a mean oil contents of 54.01% dry weight, an average single seed weight of 0.54g, and strong correlations between oil content and weight (r=0.71 to 0.72, p<0.0001), similar to the new population obtained from the greenhouse study. Correspondingly, Control seeds had a mean oil content of 50.5% dry weight, an average single seed weight of 0.44g, and moderate correlation between oil content and weight (r=0.43 to 0.44, p<0.0001), comparable to previous data on the base population. The frequency distribution of oil content and seed weight in field- and greenhouse-grown castor seeds were similar. Our results confirm that recurrent selection for high-oil content seeds is an effective approach to increase the mean oil content of a castor population.