Potato Virus Y Resistance Gene, Ry chc, Mapped to the Distal End of Potato Chromosome 9

Summary A Japanese leading cultivar ‘Konafubuki’ has an extreme resistance gene Ry _chc to Potato virus Y (PVY) in a simplex fashion. To reduce complexity of the highly heterozygous autotetraploid genome and map the Ry _chc gene, haploid plants were parthenogenetically induced from ‘Konafubuki’. The ratio of 7 resistant: 5 susceptible haploids confirmed the single dominant, simplex genotype of ‘Konafubuki’. A selected resistant haploid 98H20-5 was crossed with a susceptible diploid, resulting in 119 F ₁ plants. Using RFLP and RAPD markers, Ry _chc was mapped to the most distal end of the chromosome 9 where the recovery of recombinant genotypes was extremely reduced in this mapping population possibly due to the linked inferiority factor. The location of Ry _chc is different from those of the other extreme resistance genes to PVY, but possibly resides in one of resistance gene clusters.     

Characterization of segregation distortion on chromosome 3 induced in wide hybridization between indica and japonica type rice varieties

We previously surveyed chromosomal regions showing segregation distortion of RFLP markers in the F₂ population from the cross between a japonica type variety ‘Nipponbare’ and an indica type variety ‘Milyang23’, and showed that the most skewed segregation appeared on the short arm of chromosome 3. By comparison with the marker loci where distortion factors were previously identified, this region was assumed to be a gametophytic selection-2 (ga2) gene region. To evaluate this region, two near isogenic lines (NILs) were developed. One NIL had the ‘Nipponbare’ segment of this region on the genetic background of ‘Milyang23’ (NIL9-23), and the other NIL had the ‘Milyang23’ segment on the genetic background of ‘Nipponbare’ (NIL33-18). NIL9-23 and ‘Milyang23’, NIL33-18 and ‘Nipponbare’, and ‘Nipponbare’ and ‘Milyang23’ were respectively crossed to produce F₁ and F₂ populations. The F₁ plants of NIL9-23 × ‘Milyang23’ and NIL33-18 × ‘Nipponbare’ showed high seed fertility and the same pollen fertility as their parental cultivars, indicating that ga2 does not reduce seed and pollen fertility. Segregation ratio of a molecular marker on the ga2 region in the three F₂ populations was investigated to clarify whether segregation distortion occurred on the different genetic backgrounds. Segregation distortion of the ga2 region appeared in the both F₂ populations from the NIL9-23 and ‘Milyang23’ cross (background was ‘Milyang23’ homozygote) and the ‘Nipponbare’ and ‘Milyang23’ cross (background was heterozygote), but did notin the F₂ population from the NIL33-18 and ‘Nipponbare’ cross (background was ‘Nipponbare’ homozygote). This result indicates that ga2 interacts with a ‘Milyang23’ allele(s) on the different chromosomal region(s) to cause skewed segregation of the ga2 region. In addition, segregation ratio was the same between the F₂ populations from NIL9-23 × ‘Milyang23’ and ‘Nipponbare’ × ‘Milyang23’ crosses, suggesting that the both genotypes, ‘Milyang23’ homozygote and heterozygote, of gene(s) located on the different chromosomal region(s) have the same effect on the segregation distortion. This revised version was published online in July 2006 with corrections to the Cover Date.     

Yield, yield components and plant architecture in the F3 generation of common bean (Phaseolus vulgaris L.) derived from a cross between the determinate cultivar ‘Prelude’ and an indeterminate landrace

Growth trials were conducted outdoors in the UK to determine the yield, yield components and plant architectural differences between determinate and indeterminate Phaseolus vulgaris bean plants. F3 lines derived from crosses between ‘Prelude’, a determinate cultivar and ‘V8’, an indeterminate landrace, were grown together with the parents and ‘Carioca’, an indeterminate landrace from Brazil. Data were recorded on flowering date, number of nodes on main stem at flowering, plant height at maturity, number of pods/plant, number of seeds/pod, number of seeds/plant, 100-seed weight, seed mass/plant, percentages of diseased and healthy seeds/plant. Determinate F3 lines had significantly lower (P < 0.05) seed mass/plant, fewer pods/plant, fewer seeds/pod, fewer seeds/plant, lower harvest index, shorter stems, earlier date of flowering, fewer nodes at flowering and fewer healthy seeds/plant than indeterminate F3 lines. However, determinate genotypes had significantly larger (P < 0.05) pods to accommodate their larger seeds compared with indeterminate lines. A similar situation was found when the yield and yield components of ‘V8’, ‘Prelude’ and ‘Carioca’ were evaluated; the highest seed mass/plant was given by ‘V8’ and the lowest by ‘Prelude’. Furthermore, some indeterminate genotypes with Type IV growth habit yielded significantly higher (P < 0.05) than the high-yielding parent, ‘V8’, indicating a positive influence on seed yield by crossing different genotypes.     

Identification and mapping of a quantitative trait locus controlling extreme late bolting in Chinese cabbage (Brassica rapa L. ssp. pekinensis syn. campestris L.) using bulked segregant analysis

DNA markers linked to a locus controlling an extreme late bolting trait, which was originally found in a local cultivar of a non-heading leafy vegetable,‘Osaka Shirona Bansei’ (Brassica rapa L. ssp. pekinensis syn. campestris L.) were identified using bulked segregant analysis. A doubled haploid (DH) line, DH27, which is a progeny of ‘Osaka Shirona Bansei’, shows extreme late bolting, and bolts without vernalization. DH27 was crossed with a normal bolting DH line, G309. The plantlets of the parents, F₁ and F₂, were vernalized and then grown in a greenhouse. The bolting time of F₂ plants showed a continuous distribution from 19 to 231 days after vernalization (DAV), suggesting the effects of a few major genes and polygenes. Possible linkage markers for this trait were screened by modified bulked segregant analysis (BSA). The BSA using four bulks suggested that a 530-bp RAPD band RA1255C was linked to a locus controlling the bolting trait. The RAPD band was cloned and used as a probe to detect RFLP. The fragment detected a single locus, BN007-1,the segregation of which in the F₂ population matched that of RA1255C. Three other RAPDs were found to be linked to BN007-1. A quantitative trait locus(QTL) affecting the bolting time was detected around BN007-1 using MAPMAKER/QTL. Since the difference between bolting times of both the parental genotypes in the F₂ was 138 days, these markers may be useful for a marker-assisted selection (MAS) in the breeding program for late bolting or bolting-resistant cultivars in B. rapa crops. This revised version was published online in July 2006 with corrections to the Cover Date.     

Zingiberene-mediated resistance to the South American tomato pinworm derived from Lycopersicon hirsutum var. hirsutum

The Lycopersicon hirsutum var. hirsutum accession PI 127826 is recognized as a good source of resistance to arthropod pests due to the action of the allelochemical zimgiberene, a sesquiterpene present in its glandular trichomes. Five genotypes were selected from the F₂ generation of the interspecific cross Lycopersicon esculentum ‘TOM-556’ × Lycopersicon hirsutum var. hirsutum ‘PI 127826’, based on their low levels (BPX-368-clone#56) or high levels(BPX-368-clone#92, BPX-368-clone#105,BPX-368-clone#179, BPX-368-clone#250) of zingiberene. The five F₂ genotypes were tested for resistance to the South American tomato pinworm Tuta absolutaalong with accession L. esculentum ‘TOM-556’ (pinworm susceptible), and the accessions L. hirsutum var. hirsutum ‘PI 127826’ and L. pennellii ‘LA716’ (resistant). The F₂ clones selected for high foliar zingiberene levels showed lower scores for leaflet lesion type(LLT), percent leaflets attacked (PLA) and overall plant damage (OPD) than the low zingiberene genotypes. The results indicated that zingiberene mediates resistance to the South American pinworm, based on feeding and on ovipositing deterrence, in populations derived from the interspecific cross between Lycopersicon. esculentum and Lycopersicon hirsutum var. hirsutum. Indirect selection for high foliar zingiberene content is suggested as an efficient technique for breeding tomatoes for resistance to the South American tomato pinworm. This revised version was published online in July 2006 with corrections to the Cover Date.     

Pollination with gamma-irradiated pollen and development of fruits,seeds and parthenogenetic plants in apple

Summary Four apple (Malus X domestica) genotypes, Erovan, Golden Delicious, R1-49 and X6677, were pollinated with a marked pollen irradiated by -rays at doses ranging from 125 to 1000 Gy. Pollination with such irradiated pollen affected fruit set, seed number and seed contents, and induced the formation of parthenocarpic fruits and the development of parthenogenetic embryos. The immature embryos extracted from seeds. 2 and 3 months after pollination, were cultured in vitro and germinated after 2 months of cold treatment (3°C). Haploid plants were obtained in all 4 genotypes, after pollination with pollen irradiated at doses from 200 to 500 Gy. The optimum conditions for induction of apple haploids, by irradiated pollen approach, have been established.     

Effect of incubation temperature regimes and culture medium on broccoli microspore culture embryogenesis

Conditions for reliable induction of embryogenesis from isolated microspores were studied in ten genotypes of broccoli. Embryo yields were significantly increased in almost all of the broccoli genotypes by the incubation at 32.5 ^°C for 1 day, than when the standard incubation at 30 ^°C for 2 days was used. Treatments of 48 hours at 32.5 ^°C produced less than optimal results suggesting that broccoli microspores are more sensitive to high temperatures than those of B. napus. The use of the ¹/₂ NLN-13 medium yielded greater number of embryos than the standard NLN-13. The magnitude of the response to the redution of the concentration of major salts by half in the NLN medium varied with the different genotypes. High embryogenic broccoli cultivars, such as ‘Shogun’, ‘SDB9’, and ‘Green Valiant’, presented a better response to the reduction of the concentration of major salts by half in NLN-13. Reduction never produced a detrimental effect on embryo yield and seems not to have any effect in the subsequent development of embryos in plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Anther culture in connection with induced mutations for rice improvement

Doubled haploids have long been recognized as a valuable tool in plant breeding since it not only offers the quickest method of advancing heterozygous breeding lines to homozygosity, but also increases the selection efficiency over conventional procedures due to better discrimination between genotypes within any one generation. Ten cultivars of japonica rice and nine cultivars of indica rice were evaluated for androgenic response. Various doses (10–50 Gy) of gamma rays were applied to investigate the effect of radiation on callus formation, green plant regeneration and the frequency of selected doubled haploid mutants. Similarly, the effects of colchicine concentration (10–200 mg/l) on callus induction, regeneration and fertility of green plants were observed. It was demonstrated that the dose of 20 Gy gamma rays and 30 mg/l concentration of colchicine have significant stimulation effect on regeneration of green plants from rice anther culture. The high frequency of observed doubled haploid mutants indicates that anther culture applied in connection with gamma rays is an effective way to improve rice cultivars. This revised version was published online in August 2006 with corrections to the Cover Date.     

RAPD markers linked to a clubroot-resistance locus in Brassica rapa L.

Linkage of random amplified polymorphic DNA (RAPD) markers with resistance genes to clubroot (Plasmodiophora brassicae Wor.) in Brassica rapa L. was studied in a doubled haploid (DH population obtained by microspore culture. Thirty-six DH lines were obtained from F₁ plants from a cross between susceptible ‘Homei P09’ and resistant ‘Siloga S2’ plants. ‘Homei P09’ was a DH line obtained by microspore culture of the Chinese cabbage variety ‘Homei’, which is highly responsive in microspore culture. The resistant line ‘Siloga S2’ was obtained by two rounds of selfing of the fodder turnip ‘Siloga’. Three RAPD markers, RA12-75A, WE22B and WE49B, were found to be linked to a clubroot-resistance locus. These three markers were linked in the DH lines and an F₂ population and should be useful for marker-assisted selection in breeding programs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development of Novel Brassica napus lines with canola quality and higher levels of oleic and linoleic acids derived from intergeneric hybrids between B. napus and Orychophragmus violaceus

Parents and their F₁ and F₂ progenies were evaluated for density of type IV glandular trichomes and resistance to Tetranychus urticae Koch during three stages of the plant growth. Results indicated significant differences between density of type IV glandular trichomes on F₁ and F₂ populations at different sampling times. As age of plant increased, density of type IV glandular trichomes and resistance to two-spotted spider mite increased. Density of type IV glandular trichomes on F₂ individuals showed a broad range of variability (0–42 trichomes/mm²). The estimated heritability was very high (>85%) for damage score and density of type IV glandular trichomes at different sampling times. Acylsugars content in Lycopersicon pennellii ‘‘LA2963’’ was more than two-folds high than those found in L. esculentum ‘‘Nandi’’, F₁ and F₂ populations, indicating that recessive gene(s) are responsible for the high acylsugar contents in L. pennellii ‘‘LA2963’’.     

Chromosomal location in H. chilense and expression of common bunt resistance in wheat addition lines

The inheritance of resistance to yellow mosaic virus spread by Bemisia tabaci Gen. in Glycine soja (Linn.) Seib. & Zucc. was studied following natural infection in the field condition. The resistant wild accession, Glycine soja was crossed with susceptible cultivars ‘Ankur’, ‘Bragg’, ‘PK 472’ and ‘Kalitur’ of Glycine max (Linn.) Merr. Resistance reactions of F₁ and F₂ plants, and individual F₂ plant derived F₃ families indicated that resistance was controlled by a single dominant gene. This revised version was published online in July 2006 with corrections to the Cover Date.     

Linked dominant alleles or inter-locus interaction results in a major shift in pomegranate fruit acidity of ‘Ganesh’ × ‘Kabul Yellow’

Summary Inheritance of fruit acidity in pomegranate (Punica granatum L.) was studied in 3 sweet or low acid (‘Ganesh’, ‘Ruby’ and ‘Kabul Yellow’) and 3 sour or high acid (‘Nana’, ‘Daru’ and ‘Double Flower’) varieties and their progenies. The F₁ and F₂ data of ‘Ganesh’ × ‘Nana’ showed that fruit acidity is monogenically controlled and the sour nature is dominant over sweet. Further, whether a genotype produces sweet or sour fruit is determined by a major gene (SS) while a few modifiers with small effects cause fluctuations in the acidity levels within sour and sweet types. All the trees of 3 crosses involving ‘Daru’ produced acidic fruits but those of (‘Ganesh’ × ‘Nana’) × ‘Daru’ reached acidity as high as 71.2 g/l which could be because of cumulative influence of modifying genes derived from the two acidic varieties ‘Nana’ and ‘Daru’. Pollination of functionally sterile ‘Double Flower’ variety with single (normal) flower types revealed that ‘Double Flower’ is a dominant mutant from an acidic fruited genotype (Ss). The segregation pattern in F₁ indicated the possible linkage between genes governing total acidity and flower type. All the F₁ hybrids between ‘Kabul Yellow’ and ‘Ganesh’ (sweet × sweet) were sour fruited with almost 8-fold jump in fruit acidity over the mid-parental value. The steep increase in acidity cannot be convincingly attributed to overdominance which is certainly rare at major gene level. Alternatively, linked dominant alleles or epistatic effect of neighboring loci which readily simulate overdominance (pseudo-overdominance) could have caused a major shift in F₁ fruit acidity.     

RAPD markers linked to microspore embryogenic ability in Brassica crops

In order to identify the markers linked to microspore embryogenic ability in Brassica crops, RAPD segregation analyses were performed in a microspore-derived (MD) population and a F₂ population derived from F₁between ‘Ho Mei’ (high responsive parent in microspore embryogenesis) and ‘269’ (low responsive parent) in Chinese cabbage, and between ‘Lisandra’ (high responsive parent) and ‘Kamikita’ (low responsive parent) in oil seed rape. After 230 and 143 primers were screened, a total of 148 and 52markers were detected to be polymorphic between the parents in Chinese cabbage and oilseed rape, respectively. Twenty-seven percent of the markers in the MD population showed a significant segregation distortion in both crops. Of the markers showing segregation distortion in the MD population, 71–75% of the markers followed the expected Mendelian segregation ratio in the F₂ population. When the relationships between such distorted markers and microspore embryogenesis of the F₂ population were examined, 7 and 3 markers were identified to be associated with embryogenic ability in Chinese cabbage and oilseed rape, respectively. These markers showed additive effects on embryo yields, and the plants having more alleles of the high responsive parent produced higher embryo yields. These markers maybe useful in marker-assisted selection for improving microspore responsiveness straits in Brassica crops. This revised version was published online in July 2006 with corrections to the Cover Date.     

Direct as well as indirect somatic embryogenesis from immature (unemerged) inflorescence of a minor millet Paspalum scrobiculatum L.

Somatic embryos differentiated directly on the rachis of immature inflorescences of Paspalum scrobiculatum L. cv. PSC 1 on culture to MS or N₆ medium supplemented with different concentrations (4.5–22.5 μM) of 2,4-dichlorophenoxyacetic acid (2,4-D). Direct embryogenesis on the rachis of inflorescence explants forms the first instance in graminaceous plants. Highest frequency of direct embryogenesis (34%and 30% cultures, respectively) was possible on N₆ medium supplemented with 4.5 μM of 2,4-D and MS medium fortified with9.0 μM of 2,4-D. Other tissues of the explant, floral-primordia, only after an initial phase of callusing differentiated into somatic embryos; indirect embryogenesis. Somatic embryogenesis, direct as well as indirect, was resolved by scanning electron microscopy. The somatic embryos germinated and developed into plantlets on regeneration medium. Interestingly, one week incubation of somatic embryos on activated charcoal (0.5%) fortified basal medium, supported high potential for ‘germination’ on transfer to charcoal-free basal medium. This beneficial effect of activated charcoal on regeneration of somatic embryos into plantlets is the first record in the Gramineae. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inheritance of resistance to <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">melonis</Emphasis> races 0 and 2 in melon accession Tortuga

The inheritance of the resistance to Fusarium oxysporum f. sp. melonis (F.o.m.) races 0 and 2 in ‘Tortuga’, a Spanish cantalupensis accession, was studied from crosses of ‘Tortuga’ by the susceptible line ‘Piel de Sapo’ and the resistant one ‘Charentais-Fom1’ that carries the resistance gene Fom-1. The segregation patterns observed in the F₂ (‘Tortuga’ × ‘Piel de Sapo’) and the backcross (‘Piel de Sapo’ × (‘Tortuga’ × ‘Piel de Sapo’) populations, suggest that resistance of ‘Tortuga’ to races 0 and 2 of F.o.m. is conferred by two independent genes: one dominant and the other recessive. In the F2 derived from the cross between accessions ‘Tortuga’ and ‘Charentais-Fom1’, the lack of susceptible plants indicated that the two accessions are carrying the same resistance gene (Fom-1). The analysis of 158 F₂ plants (‘Tortuga’ × ‘Piel de Sapo’) with a Cleaved Amplified Polymorphic Sequence marker 618-CAPS, tightly linked to Fom-1 (0.9 cM), confirmed that ‘Tortuga’ also carries a recessive gene, that we propose to symbolize by fom-4.     

Segregation distortion of Brassica carinata derived black rot resistance in Brassica oleracea

Three segregating F₂ populations were developed by self-pollinating 3 black rot resistant F₁ plants, derived from across between black rot resistant parent line 11B-1-12 and the susceptible cauliflower cultivar ‘Snow Ball’. Plants were wound inoculated using 4 isolates ofXanthomonas campestris pv. campestris (Xcc) race 4, and disease severity ratings of F₂ plants from the three populations were scored. A total of 860 arbitrary oligonucleotide primers were used to amplify DNA from black rot resistant and susceptible F₂ plants and bulks. Eight RAPD markers amplified fragments associated with completely disease free plants following black rot inoculation,which segregated in frequencies far lower than expected. Segregation of markers with black rot resistance indicates that a single, dominant major gene controls black rot resistance in these plants. Stability of this black rot resistance gene in populations derived from 11B-1-12 may complicate introgression into B. oleracea genotypes for hybrid production. This revised version was published online in July 2006 with corrections to the Cover Date.     

Inheritance mode of male sterility in bunching onion (<Emphasis Type="Italic">Allium fistulosum</Emphasis> L.) accessions

Cytoplasmic male sterility (CMS) is an indispensable trait for F₁ hybrid seed production in bunching onion (Allium fistulosum L.). Expansion of the cytoplasmic diversity of F₁ hybrid cultivars by introduction of various CMS resources has great potential to eliminate vulnerability to cytoplasm type-specific diseases. This study aimed to evaluate appearance frequency of male sterile plants in several bunching onion accessions and to identify CMS resources. In eight (‘Nogiwa Aigara’, ‘Bansei Hanegi’, ‘Amarume’, ‘Kimnung’, ‘Zhangqiu’, ‘INT/CHN/1990/GOTOU’, ‘Natsunegi’ and ‘Guangzhou’) of 135 accessions collected from Japan, China, Mongolia, Korea and Taiwan, male sterile plants appeared with varied frequencies from 1.7% (‘Nogiwa Aigara’ and ‘Bansei Hanegi’) to 24.5% (‘Zhangqiu’). The inheritance mode of Zhangqiu- and Guangzhou-derived male sterility was confirmed to be CMS by sib-crossings and interbreed crossings. Microscopic examination of microsporogenesis in the CMS plants revealed that microspore protoplasm rapidly degenerated without mitotic division after the release of microspores from tetrads. The CMS germplasm described here would be useful for the development of “A” lines to be used in F₁ hybrid seed production of bunching onion. Male fertility in ‘Nogiwa Aigara’, ‘Bansei Hanegi’, ‘Kimnung’, ‘INT/CHN/1990/GOTOU’ and ‘Natsunegi’ was verified to be controlled by a single fertility restoration locus.     

Pear mutagenesis: In vitro treatment with gamma-rays and field selection for productivity and fruit traits

In vitro shoots of six pear (Pyrus communis L.) cultivars, ‘Conference’, ‘Doyennéd'Hiver’, ‘Passe Crassane’, ‘Bartlett’, ‘AbbéFetel’ and ‘Butirra Precoce Morettini’ were irradiated with gamma rays (3.5 Gy). After three subcultures, microcuttings from the irradiated shoots and from additional non-irradiated microcuttings were rooted to establish plants for survey orchards. All trees were individually observed for variation in fruit traits and for productivity. Trees were selected for improved characters related to production such as early bearing and consistent productivity. Variations observed in fruit appearance concerned degree of russeting, fruit shape and size. The frequencies of the observed variations in fruit traits depended on the cultivar, ranging from 0.81% in ‘Doyennéd'Hiver’ to 3.64% in ‘Passe Crassane’. Of the 97 variants selected, only two showed chimeral behavior. This revised version was published online in July 2006 with corrections to the Cover Date.     

An induced brachytic mutant of chickpea and its possible use in ideotype breeding

Mutations were induced in chickpea (Cicer arietinum L.) cultivar ‘JG 315’ through treatment of seeds with ethyl methane sulphonate (EMS). One of the mutants, named JGM 1, had brachytic growth (compact growth), characterized by erect growth habit, thick and sturdy stem, short internodal and interleaflet distances and few tertiary and later order branches. It was isolated from M₂ derived from seeds treated with 0.6% EMS for 6 h. Segregation analyses in F₂ progenies of its crosses with normal chickpea genotypes (JG 315, ICC 4929, and ICC 10301) suggested that a single recessive gene controlled brachytic growth in JGM 1. This gene was not allelic to the br gene for brachytic growth in spontaneous brachytic mutant E100YM. Thus, the gene for brachytic growth in JGM 1 was designated br2 and the br gene of E100YM was redesignated br1. Efforts are being made to use JGM 1 in development of a plant type with short internodes and erect growth habit. Such plant type may resist excessive vegetative growth in high input (irrigation and fertility) conditions and accommodate more plants per unit area.     

Detecting and estimating segregation distortion and linkage between glufosinate tolerance and blackleg resistance in Brassica napus L.

Summary The segregation and linkage between glufosinate (transgenes ‘Rf3’ and ‘T177’) and blackleg resistance genes in canola (Brassica napus L.) were assessed using F₁ microspore-derived doubled haploid (DH) populations from four crosses including reciprocals, two involving the transgene ‘Rf3’ and the other two involving the transgene ‘T177’. To relax the assumption of no segregation distortion required for the conventional analysis of segregation and linkage, we employed Bailey's analysis that allows detecting segregation distortion at linked loci. The significant departures from the 1:1 segregation were detected in the crosses involving the transgene ‘T177’ but not in the crosses involving the transgene ‘Rf3’. The apparent deficit of the herbicide tolerant DH lines in the crosses with the transgene ‘T177’ is likely due to differential selection against the gametes carrying ‘T177’ during microspore culture. The linkage was strong between blackleg resistance and the transgene ‘Rf3’ but weak or absent between blackleg resistance and the transgene ‘T177’, suggesting that the two transgenes are probably inserted into distant regions of the genome. The observed linkage offers an opportunity to develop new canola cultivars with both glufosinate tolerance conferred by transgene ‘Rf3’ and blackleg resistance.