Control of Lepidopteran insect pests in transgenic Chinese cabbage (Brassica rapa ssp. pekinensis) transformed with a synthetic Bacillus thuringiensis cry1C gene

CRISPR/Cas9-Mediated HY5 Gene Editing Reduces Growth Inhibition in Chinese Cabbage (Brassica rapa) under ER Stress

Various stresses can affect the quality and yield of crops, including vegetables. In this study, CRISPR/Cas9 technology was employed to examine the role of the ELONGATED HYPOCOTYL 5 (HY5) gene in influencing the growth of Chinese cabbage (Brassica rapa). Single guide RNAs (sgRNAs) were designed to target the HY5 gene, and deep-sequencing analysis confirmed the induction of mutations in the bZIP domain of the gene. To investigate the response of Chinese cabbage to endoplasmic reticulum (ER) stress, plants were treated with tunicamycin (TM). Both wild-type and hy5 mutant plants showed increased growth inhibition with increasing TM concentration. However, the hy5 mutant plants displayed less severe growth inhibition compared to the wild type. Using nitroblue tetrazolium (NBT) and 3,3'-diaminobenzidine (DAB) staining methods, we determined the amount of reactive oxygen species (ROS) produced under ER stress conditions, and found that the hy5 mutant plants generated lower levels of ROS compared to the wild type. Under ER stress conditions, the hy5 mutant plants exhibited lower expression levels of UPR- and cell death-related genes than the wild type. These results indicate that CRISPR/Cas9-mediated editing of the HY5 gene can mitigate growth inhibition in Chinese cabbage under stresses, improving the quality and yield of crops.

L-Cysteine Increases the Transformation Efficiency of Chinese Cabbage (Brassica rapa ssp. pekinensis)

Successful Agrobacterium-mediated transformations of Chinese cabbage have been limited owing to the plant's recalcitrant nature, genomic background and explant necrosis upon infection, which hinders the transfer of T-DNA region into the Chinese cabbage. Consequently, in the current experiment, a stable Agrobacterium tumefaciens-mediated transformation method for Chinese cabbage cv. Kenshin established by employing important anti-oxidants in the co-cultivation and subsequent regeneration media. Four-day-old in vitro derived cotyledon explants were infected with A. tumefaciens strain GV3101 harboring the vector pCAMIBA1303. Cotyledon explants exposed to an Agrobacterium suspension (OD₆₀₀ of approximately 0.6) for 10 min and then incubated for 3 days co-cultivation in Murashige and Skoog medium containing an L-cysteine + AgNO₃ combination exhibited the highest β-glucuronidase (GUS) expression (94%) and explant regeneration efficiency (76%). After 3 days, the cotyledon explants were subjected to three selection cycles with gradually increasing hygromycin B concentrations (10 to 12 mg/L). The incorporation and expression of hptII in T₀ transformed plants were verified by polymerase chain reaction and Southern blot analyses. These transgenic plants (T₀) were fertile and morphologically normal. Using the present protocol, a successful transformation efficiency of 14% was achieved, and this protocol can be applied for genome editing and functional studies to improve Chinese cabbage traits.

Development of Transgenic Brassica Crops Against Biotic Stresses Caused by Pathogens and Arthropod Pests

The Brassica genus includes one of the 10 most agronomically and economically important plant groups in the world. Within this group, we can find examples such as broccoli, cabbage, cauliflower, kale, Brussels sprouts, turnip or rapeseed. Their cultivation and postharvest are continually threatened by significant stresses of biotic origin, such as pathogens and pests. In recent years, numerous research groups around the world have developed transgenic lines within the Brassica genus that are capable of defending themselves effectively against these enemies. The present work compiles all the existing studies to date on this matter, focusing in a special way on those of greater relevance in recent years, the choice of the gene of interest and the mechanisms involved in improving plant defenses. Some of the main transgenic lines developed include coding genes for chitinases, glucanases or cry proteins, which show effective results against pathogens such as Alternaria brassicae, Leptosphaeria maculans or Sclerotinia sclerotiorum, or pests such as Lipaphis erysimi or Plutella xylostella.

Myzus persicae (Hemiptera: Aphididae) infestation increases the risk of bacterial contamination and alters nutritional content in storage Chinese cabbage

BACKGROUND

Aphids are common insect pests that feed on and excrete feces/honeydew on storage vegetables, especially in the temperate region of the northern hemisphere. The honeydew of aphids is an excellent growth medium for microorganisms. To explore the effects of aphid infestation on the risk of microbial contamination and food safety: (i) the bacterial diversity and community in aphid honeydew were investigated; (ii) the nutritional components of the cabbage were analyzed; and (iii) safety was evaluated.

RESULTS

The results showed that the dominant bacteria in storage Chinese cabbage under different exposure times belonged to the phylum Proteobacteria, family Enterobacteriaceae. The richness of Enterobacteriaceae increased from 36.35% (1 day) to 39.70% (5 days) and to 50.74% (10 days) as the exposure time increased. Serratia was the genus with the highest abundance (23.38% for 1 day, 30.56% for 5 days and 37.85% for 10 days). The abundance of pathways associated with Staphylococcus aureus infection and Shigellosis increased significantly after prolonged storage. In addition, when the aphid density increased from 0 to 100 per 250 g of Chinese cabbage leaves, the protein content in Chinese cabbage decreased significantly, whereas the reducing sugar content increased significantly.

CONCLUSION

These results demonstrate that the honeydew excreted by the green peach aphid Myzus persicae (Sulzer) on storage Chinese cabbage can serve as a medium for some foodborne disease pathogens. The present study may provide both a theoretical and practical basis for vegetable storage to reduce the risk of foodborne pathogen infection and to maintain the balance of nutrients. © 2020 Society of Chemical Industry.

Principales promotores utilizados en la transformación genética de plantas

El conocimiento pleno de los promotores determina el éxito en la obtención de nuevos cultivares de plantas a través de técnicas biotecnológicas, ya que dicha secuencia del ADN regula la transcripción de otras regiones adyacentes o cercanas, encontrándose los siguientes promotores: constitutivos, tejido-específicos o estadio-específicos, inducibles y sintéticos. En esta revisión se resume de manera precisa los conceptos, ventajas y limitaciones de los distintos tipos de promotores, con ejemplos claros de ello.Palabras clave: promotor, biotecnología vegetal, transcripción genética.

A simple and efficient Agrobacterium tumefaciens-mediated plant transformation of Brassica rapa ssp. pekinensis

The present study aims to investigate the numerous factors influencing Agrobacterium tumefaciens-mediated genetic transformation of Chinese cabbage (Brassica rapa ssp. pekinensis). Factors affecting transformation efficiency, such as age of explants, Agrobacterium concentration, and effect of acetosyringone, pre-cultivation, infection and co-cultivation time of Agrobacterium were examined. The pre-cultured hypocotyls from young seedlings prior to exposure to Agrobacterium showed higher shoot regeneration. The plant transformation with the modest A. tumefaciens concentrations (0.8 OD) and the 3 days co-cultivation periods increased transformation efficiency. Plant growth hormones [1-naphthyl acetic acid (NAA) and 6-benzyl amino purine (BAP)] were essential for callus and shoot formation. Root formation was effective in half strength MS medium without supplementation of root-inducing hormones. To maintain selection pressure, plant subculture was carried out every 2 weeks with selective antibiotics. The putative transgenic plants were acclimatized in the greenhouse. Polymerase chain reaction was performed to confirm the integration of T-DNA into the genome of transgenic plants. A transformation efficiency of 15 % was obtained. This protocol allows effective transformation and indirect regeneration of Brassica rapa.

Biotechnological advancement in genetic improvement of broccoli (Brassica oleracea L. var. italica), an important vegetable crop

With the advent of molecular biotechnology, plant genetic engineering techniques have opened an avenue for the genetic improvement of important vegetable crops. Vegetable crop productivity and quality are seriously affected by various biotic and abiotic stresses which destabilize rural economies in many countries. Moreover, absence of proper post-harvest storage and processing facilities leads to qualitative and quantitative losses. In the past four decades, conventional breeding has significantly contributed to the improvement of vegetable yields, quality, post-harvest life, and resistance to biotic and abiotic stresses. However, there are many constraints in conventional breeding, which can only be overcome by advancements made in modern biology. Broccoli (Brassica oleracea L. var. italica) is an important vegetable crop, of the family Brassicaceae; however, various biotic and abiotic stresses cause enormous crop yield losses during the commercial cultivation of broccoli. Thus, genetic engineering can be used as a tool to add specific characteristics to existing cultivars. However, a pre-requisite for transferring genes into plants is the availability of efficient regeneration and transformation techniques. Recent advances in plant genetic engineering provide an opportunity to improve broccoli in many aspects. The goal of this review is to summarize genetic transformation studies on broccoli to draw the attention of researchers and scientists for its further genetic advancement.

Co-expression of chimeric chitinase and a polygalacturonase-inhibiting protein in transgenic canola (Brassica napus) confers enhanced resistance to Sclerotinia sclerotiorum

OBJECTIVES

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum is one of the major fungal diseases of canola. To develop resistance against this fungal disease, the chit42 from Trichoderma atroviride with chitin-binding domain and polygalacturonase-inhibiting protein 2 (PG1P2) of Phaseolus vulgaris were co-expressed in canola via Agrobacterium-mediated transformation.

RESULTS

Stable integration and expression of transgenes in T0 and T2 plants was confirmed by PCR, Southern blot and RT-PCR analyses. Chitinase activity and PGIP2 inhibition were detected by colorimetric and agarose diffusion assay in transgenic lines but not in untransformed plants. The crude proteins from single copy transformant leaves having high chitinase and PGIP2 activity (T16, T8 and T3), showed up to 44 % inhibition of S. sclerotiorum hyphal growth. The homozygous T2 plants, showing inheritance in Mendelian fashion (3:1), were further evaluated under greenhouse conditions for resistance to S. sclerotiorum. Intact plants contaminated with mycelia showed resistance through delayed onset of the disease and restricted size and expansion of lesions as compared to wild type plants.

CONCLUSIONS

Combined expression of chimeric chit42 and pgip2 in Brassica napus L. provide subsequent protection against SSR disease and can be helpful in increasing the canola production in Iran.

Enhanced resistance to Sclerotinia sclerotiorum in Brassica napus by co-expression of defensin and chimeric chitinase genes

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the major fungal diseases of Brassica napus L. To develop resistance against this fungal disease, the defensin gene from Raphanus sativus and chimeric chit42 from Trichoderma atroviride with a C-terminal fused chitin-binding domain from Serratia marcescens were co-expressed in canola via Agrobacterium-mediated transformation. Twenty transformants were confirmed to carry the two transgenes as detected by polymerase chain reaction (PCR), with 4.8 % transformation efficiency. The chitinase activity of PCR-positive transgenic plants were measured in the presence of colloidal chitin, and five transgenic lines showing the highest chitinase activity were selected for checking the copy number of the transgenes through Southern blot hybridisation. Two plants carried a single copy of the transgenes, while the remainder carried either two or three copies of the transgenes. The antifungal activity of two transgenic lines that carried a single copy of the transgenes (T4 and T10) was studied by a radial diffusion assay. It was observed that the constitutive expression of these transgenes in the T4 and T10 transgenic lines suppressed the growth of S. sclerotiorum by 49 % and 47 %, respectively. The two transgenic lines were then let to self-pollinate to produce the T₂ generation. Greenhouse bioassays were performed on the transgenic T₂ young leaves by challenging with S. sclerotiorum and the results revealed that the expression of defensin and chimeric chitinase from a heterologous source in canola demonstrated enhanced resistance against sclerotinia stem rot disease.

Agrobacterium-mediated high-frequency transformation of an elite commercial maize (Zea mays L.) inbred line

An improved Agrobacterium -mediated transformation protocol is described for a recalcitrant commercial maize elite inbred with optimized media modifications and AGL1. These improvements can be applied to other commercial inbreds. This study describes a significantly improved Agrobacterium-mediated transformation protocol in a recalcitrant commercial maize elite inbred, PHR03, using optimal co-cultivation, resting and selection media. The use of green regenerative tissue medium components, high copper and 6-benzylaminopurine, in resting and selection media dramatically increased the transformation frequency. The use of glucose in resting medium further increased transformation frequency by improving the tissue induction rate, tissue survival and tissue proliferation from immature embryos. Consequently, an optimal combination of glucose, copper and cytokinin in the co-cultivation, resting and selection media resulted in significant improvement from 2.6 % up to tenfold at the T0 plant level using Agrobacterium strain LBA4404 in transformation of PHR03. Furthermore, we evaluated four different Agrobacterium strains, LBA4404, AGL1, EHA105, and GV3101 for transformation frequency and event quality. AGL1 had the highest transformation frequency with up to 57.1 % at the T0 plant level. However, AGL1 resulted in lower quality events (defined as single copy for transgenes without Agrobacterium T-DNA backbone) when compared to LBA4404 (30.1 vs 25.6 %). We propose that these improvements can be applied to other recalcitrant commercial maize inbreds.

Development and bioassay of transgenic Chinese cabbage expressing potato proteinase inhibitor II gene

Lepidopteran larvae are the most injurious pests of Chinese cabbage production. We attempted the development of transgenic Chinese cabbage expressing the potato proteinase inhibitor II gene (pinII) and bioassayed the pest-repelling ability of these transgenic plants. Cotyledons with petioles from aseptic seedlings were used as explants for Agrobacterium-mediated in vitro transformation. Agrobacterium tumefaciens C58 contained the binary vector pBBBasta-pinII-bar comprising pinII and bar genes. Plants showing vigorous PPT resistance were obtained by a series concentration selection for PPT resistance and subsequent regeneration of leaf explants dissected from the putative chimera. Transgenic plants were confirmed by PCR and genomic Southern blotting, which showed that the bar and pinII genes were integrated into the plant genome. Double haploid homozygous transgenic plants were obtained by microspore culture. The pinII expression was detected using quantitative real time polymerase chain reaction (qRT-PCR) and detection of PINII protein content in the transgenic homozygous lines. Insect-feeding trials using the larvae of cabbage worm (Pieris rapae) and the larvae of the diamondback moth (Plutella xylostella) showed higher larval mortality, stunted larval development, and lower pupal weights, pupation rates, and eclosion rates in most of the transgenic lines in comparison with the corresponding values in the non-transformed wild-type line.

Vegetables

The conscious promotion of health by an appropriate, balanced diet has become an important social request. Vegetable thereby possesses a special importance due to its high vitamin, mineral and dietary fibre content. Major progress has been made over the past few years in the transformation of vegetables. The expression of several genes has been inhibited by sense gene suppression, and new traits caused by new gene constructs are stably inherited. This chapter reviews advances in various traits such as disease resistance, abiotic stress tolerance, quality improvement, pharmaceutical and industrial application. Results are presented from most important vegetable families, like Solanaceae, Brassicaceae, Fabaceae, Cucurbitaceae, Asteraceae, Apiaceae, Chenopodiaceae and Liliaceae. Although many research trends in this report are positive, only a few transgenic vegetables have been released from confined into precommercial testing or into use.

Enhancement of tolerance to soft rot disease in the transgenic Chinese cabbage (Brassica rapa L. ssp. pekinensis) inbred line, Kenshin

We developed a transgenic Chinese cabbage (Brassica rapa L. ssp. pekinensis) inbred line, Kenshin, with high tolerance to soft rot disease. Tolerance was conferred by expression of N-acyl-homoserine lactonase (AHL-lactonase) in Chinese cabbage through an efficient Agrobacterium-mediated transformation method. To synthesize and express the AHL-lactonase in Chinese cabbage, the plant was transformed with the aii gene (AHL-lactonase gene from Bacillus sp. GH02) fused to the PinII signal peptide (protease inhibitor II from potato). Five transgenic lines were selected by growth on hygromycin-containing medium (3.7% transformation efficiency). Southern blot analysis showed that the transgene was stably integrated into the genome. Among these five transgenic lines, single copy number integrations were observed in four lines and a double copy number integration was observed in one transgenic line. Northern blot analysis confirmed that pinIISP-aii fusion gene was expressed in all the transgenic lines. Soft rot disease tolerance was evaluated at tissue and seedling stage. Transgenic plants showed a significantly enhanced tolerance (2-3-fold) to soft rot disease compared to wild-type plants. Thus, expression of the fusion gene pinIISP-aii reduces susceptibility to soft rot disease in Chinese cabbage. We conclude that the recombinant AHL-lactonase, encoded by aii, can effectively quench bacterial quorum-sensing and prevent bacterial population density-dependent infections. To the best of our knowledge, the present study is the first to demonstrate the transformation of Chinese cabbage inbred line Kenshin, and the first to describe the effect of the fusion gene pinIISP-aii on enhancement of soft rot disease tolerance.

Impact of single-gene and dual-gene Bt broccoli on the herbivore Pieris rapae (Lepidoptera: Pieridae) and its pupal endoparasitoid Pteromalus puparum (Hymenoptera: Pteromalidae)

Transgenic brassica crops producing insecticidal proteins from Bacillus thuringiensis (Bt) are being investigated as candidates for field release to control lepidopteran pests. Information on the potential impact of Bt brassica crops on pests and non-target natural enemies is needed as part of an environmental risk assessment prior to the commercial release. This first tier study provides insight into the tritrophic interactions among Bt broccoli plants, the herbivore Pieris rapae and its parasitoid Pteromalus puparum. We first evaluated the efficacy of three types of Bt broccoli plants, cry1Ac, cry1C and cry1Ac + cry1C, on different instars of P. rapae. Bt broccoli effectively controlled P. rapae larvae, although later instars were more tolerant. The efficacy of different Bt broccoli plants on P. rapae larvae was consistently cry1Ac > cry1Ac + cry1C > cry1C. When the parasitoid P. puparum developed in a P. rapae pupa (host) that had developed from Bt plant-fed older larvae, developmental time, total number and longevity of the P. puparum generated from the Bt plant-fed host were significantly affected compared with those generated from the non-Bt control plant-fed host. Simultaneously, negative effects on P. rapae pupae were found, i.e. pupal length, width and weight were significantly reduced after older P. rapae larvae fed on different Bt plants for 1 or 2 days. Cry1C toxin was detected using ELISA in P. rapae pupae after older larvae fed on cry1C broccoli. However, no Cry1C toxin was detected in newly emerged P. puparum adults developing in Bt-fed hosts. Only a trace amount of toxin was detected from entire P. puparum pupae dissected from the Bt plant-fed host. Moreover, no negative effect was found on the progeny of P. puparum developing from the Bt plant-fed host when subsequently supplied with a healthy host, P. rapae pupae. The reduced quality of the host appears to be the only reason for the observed deleterious effects on P. puparum. Our data suggest that the effects on P. puparum developing in Bt plant-fed P. rapae are mediated by host quality rather than by direct toxicity.

Successful genetic transformation of Chinese cabbage using phosphomannose isomerase as a selection marker

A mannose selection system was adapted for use in the Agrobacterium-mediated transformation of Chinese cabbage. This system makes use of the pmi gene that encodes phosphomannose isomerase, which converts mannose-6-phosphate to fructose-6-phosphate. Hypocotyl explants from 4-5-day-old seedlings of Chinese cabbage inbred lines were pre-cultured for 2-3 days and then infected with Agrobacterium. Two genes (L: -guluno-gamma-lactone oxidase, GLOase, and jasmonic methyl transferase, JMT) were transformed into Chinese cabbage using the transformation procedure developed in this study. We found that supplementing the media with 7 g l(-1) mannose and 2% sucrose provides the necessary conditions for the selection of transformed plants from nontransformed plants. The transformation rates were 1.4% for GLOase and 3.0% for JMT, respectively. The Southern blot analysis revealed that several independent transformants (T (0)) were obtained from each transgene. Three different inbred lines were transformed, and most of the T (1) plants had normal phenotypes. The transformation method presented here for Chinese cabbage using mannose selection is efficient and reproducible, and it can be useful to introduce a desirable gene(s) into commercially useful inbred lines of Chinese cabbage.

Novel insect resistance in Brassica napus developed by transformation of chitinase and scorpion toxin genes

Transgenic plants with introduced pest-resistant gene offer an efficient alternative insect control. The novel insect-resistant gene combination, chitinase(chi) and BmkIT(Bmk), containing an insect-specific chitinase gene and a scorpion insect toxin gene was introduced into Brassica napus cultivar via Agrobacterium-mediated transformation. Fifty-seven regenerated plantlets with kanamycin-resistance were obtained. Transgenic plants were verified by Southern blot analysis. Enzyme-linked immunosorbent assay (ELISA) and bioassay of artificial inoculation with diamondback moth (Plutella maculipenis) (DBM) larvae indicated that some of the transgenic plants were high-level expression for both chitinase and scorpion toxin proteins and performed high resistance against the tested pest infestation. The genetic analysis of T(1) progeny confirmed that the inheritance of introduced genes followed the Mendelian rules.

TransgenicBt-producingBrassica napus:Plutella xylostellaselection pressure and fitness of weedy relatives

Release of transgenic insect-resistant crops creates the potential not only for the insect pest to evolve resistance but for the escape of transgenes that may confer novel or enhanced fitness-related traits through hybridization with their wild relatives. The differential response of diamondback moth (Plutella xylostella) populations in eastern and western Canada to Bt-producing (GT) Brassica napus and the potential for enhanced fitness of GT B. napus and weedy GT Brassica rapa x B. napus hybrid populations (F1, BC1, BC2) were studied. Comparative bioassays using neonates and 4th instars showed that GT B. napus and GT B. rapa x B. napus hybrids are lethal to larvae from both populations. No measurable plant fitness advantage (reproductive dry weight) was observed for GT B. napus (crop) and GT B. rapa x B. napus hybrid populations at low insect pressure (1 larva per leaf). At high insect densities (>10 larvae per leaf), vegetative plant weight was not significantly different for GT B. napus and non-GT B. napus, whereas reproductive plant weight and proportion of reproductive material were significantly higher in GT B. napus. Establishment of the Bt trait in wild B. rapa populations may also increase its competitive advantage under high insect pressure.

Field performance of transgenic tall fescue (Festuca arundinacea Schreb.) plants and their progenies

Tall fescue (Festuca arundinacea Schreb.) is a hexaploid, outcrossing grass species widely used for forage and turf purposes. Transgenic tall fescue plants were generated by biolistic transformation of embryogenic cell suspension cultures that were derived from single genotypes of widely used cultivar Kentucky-31. Primary transgenics from two genotypes, their corresponding regenerants from the same genotypes and control seed-derived plants were transferred to the field and evaluated for 2 years. Progenies of these three classes of plants were obtained and evaluated together with seed-derived plants in a second field experiment. The agronomic characteristics evaluated were: heading date, anthesis date, height, growth habit, number of reproductive tillers, seed yield and biomass. The agronomic performance of the primary transgenics and regenerants was generally inferior to that of the seed-derived plants, with primary transgenics having fewer tillers and a lower seed yield. However, no major differences between the progenies of transgenics and the progenies of seed-derived plants were found for the agronomic traits evaluated. Primary transgenics and regenerants from the same genotype were more uniform than plants from seeds. Progenies of transgenics performed similarly to progenies of the regenerants. The addition of a selectable marker gene in the plant genome seems to have had little effect on the agronomic performance of the regenerated plants. No indication of weediness of the transgenic tall fescue plants was observed. Our results indicate that outcrossing grass plants generated through transgenic approaches can be incorporated into forage breeding programs.

Bt-transgenic oilseed rape hybridization with its weedy relative,Brassica rapa

The movement of transgenes from crops to weeds and the resulting consequences are concerns of modern agriculture. The possible generation of "superweeds" from the escape of fitness-enhancing transgenes into wild populations is a risk that is often discussed, but rarely studied. Oilseed rape, Brassica napus (L.), is a crop with sexually compatible weedy relatives, such as birdseed rape (Brassica rapa (L.)). Hybridization of this crop with weedy relatives is an extant risk and an excellent interspecific gene flow model system. In laboratory crosses, T3 lines of seven independent transformation events of Bacillus thuringiensis (Bt) oilseed rape were hybridized with two weedy accessions of B. rapa. Transgenic hybrids were generated from six of these oilseed rape lines, and the hybrids exhibited an intermediate morphology between the parental species. The Bt transgene was present in the hybrids, and the protein was synthesized at similar levels to the corresponding independent oilseed rape lines. Insect bioassays were performed and confirmed that the hybrid material was insecticidal. The hybrids were backcrossed with the weedy parent, and only half the oilseed rape lines were able to produce transgenic backcrosses. After two backcrosses, the ploidy level and morphology of the resultant plants were indistinguishable from B. rapa. Hybridization was monitored under field conditions (Tifton, GA, USA) with four independent lines of Bt oilseed rape with a crop to wild relative ratio of 1200:1. When B. rapa was used as the female parent, hybridization frequency varied among oilseed rape lines and ranged from 16.9% to 0.7%.