Taxonomy of Portuguese Tronchuda cabbage and Galega kale landraces using morphological characters,nuclear RFLPs,and isozyme analysis: A review

Summary Morphological characters, nuclear RFLPs, and isozyme analysis were used to study the similarity between 32 Portuguese Tronchuda cabbage and Galega kale landraces, and some cabbage cultivars traditionally grown in Portugal. Forty-six morphological characters observed in two consecutive years, RFLP data from 55 nuclear probes, detecting 291 polymorphic nuclear DNA restriction fragments, and allelic frequencies in 21 putative loci, generated by nine isozymes, were analyzed by the unweighted pair group method, using arithmetic averages (UPGMA), in order to present the results in the form of a phenogram. The three methods resulted in different clustering patterns of the 32 cole accessions. Morphological characters gave consistent clustering according to the traditional landrace definition and denomination, producing clear separation between Tronchuda cabbages and Galega kales. RFLPs were unable to separate Tronchuda cabbages from Galega kales and defined five landrace groups corresponding to their geographic origins rather than to their morphological similarities. Isozymes showed poor accession discrimination and an intermediate clustering pattern with some accessions being clustered according to their geographic origins and others according to their morphological similarities. Portuguese Tronchuda cabbages and Galega kales constitute a distinct and relatively homogenous group within Brassica oleracea, sharing the same genetic background. It is concluded that Portuguese coles have evolved independently from a common ancestor to the present cultivated forms. Portugal should be considered as an important region of domestication of specialized leafy coles.     

Morphological characterization of kale populations from northwestern Spain

Crops belonging to the genus Brassicaare widely grown in Galicia (northwesternSpain). Kales (Brassica oleracea L.convar. acephala (DC.) Alef.) are oneof the most important Brassica cropsin this region where landraces aretraditionally grown by farmers on smallplots for either human or animal food.Fifteen kale populations from northwesternSpain were evaluated in two locations andtwo planting dates (early and late). Theobjectives were i) to study theirmorphological diversity, ii) to determinetheir relationships, and iii) to evaluatetheir morphological and agronomiccharacteristics that could be incorporatedto breeding programs in the future.Significant differences were found amongpopulations for all traits while genotype ×environment interaction was not significantfor most of them. Cluster and principalcomponent analysis were performed todetermine relationships among landraces andto obtain information on the usefulness ofthe characters for the definition ofgroups. The phenogram showed five groups,two groups including most of thepopulations and three small independentgroups. Groups of landraces were associatedwith the geographical origin and withmorphological differences amongpopulations, mainly with the length oftheir vegetative phase: north and earlypopulations (cluster A) and south and latepopulations (cluster B). Morphologicaldiversity was higher in coastal populationsthan in inland populations. As conclusion,the populations evaluated in this workdisplay a wide diversity of traits whichenable us to select and combine someinteresting landraces for important traitsin order to obtain improved varieties.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Components of variation,heritabilities and correlations for indices of sprouting tolerance and seed dormancy in Triticum spp.

Summary RFLPs were used to study the genetic relationships of 31 Portuguese coles (Brassica oleracea L.) representing the different ecotypes or landraces grown in Portugal. Other cole crops such as Jersey kale, Chinese kales, common cabbages, broccolis and cauliflower, two nine-chromosome wild species, and one accession of turnip also were included to determine the evolutionary relationships of Portuguese coles to other related coles. Principal coordinates and cluster analyses were conducted using a package of computer programs and RFLP data from 55 nuclear DNA probes, detecting 291 polymorphic restriction fragments. The results showed that the 48 accessions clustered into five groups: (a) a dispersed group with turnip and the wild brassicas; (b) Chinese kales; (c) broccolis and cauliflower; (d) a disperse group including Algarve and Jersey kales, thousand head kale, cabbages, and savoy cabbage; (e) a large and compact group containing all Portuguese tronchuda cabbages and kales. This unique and closely related group containing Portuguese tronchuda cabbages and kales could be further divided into five subgroups corresponding to the major areas of cultivation. The phenetic groupings of Portuguese tronchuda cabbages and kales based on RFLP data corresponded more with their geographic origins (collecting sites) than with their morphological similarities. A mechanism involving geographic isolation and frequent intercrossing within local areas is proposed to explain genetic relationships among Portuguese tronchuda cabbages and kales.     

Screening of Portuguese cole landraces (Brassica oleracea L.) with Leptosphaeria maculans and Xanthomonas campestris pv. campestris

Summary Fifty-six landraces of Portuguese coles (Brassica oleracea l.), representing fourteen morphotypes, were screened for resistance to Leptosphaeria maculans at the cotyledon stage. Three isolates of the pathogen belonging to three pathogenicity groups were used in the screening. The mean disease interaction phenotype of the B. oleracea landraces with the L. maculans isolates confirmed their differences in pathogenicity. When compared to pathogenicity grouping using a B. napus differential set, a different classification was observed on B. oleracea for the three L. maculans isolates, suggesting possible differences in the genetic interaction between the two plant species and the pathogen. Most of the Portuguese cole landraces were found to be susceptible to all three isolates of L. maculans, although a few have shown intermediate interaction phenotype. Some accessions, on the other hand, elicit a differential reaction with the three isolates tested, and can be further selected to be used in host differential sets or in breeding for resistance to black leg.Fifty-four landraces of Portuguese coles, representing eleven morphotypes, were also screened in the field for resistance to Xanthomonas campestris pv. campestris. A good level of resistance to the bacterium was found in several of the morphotypes.Accessions of the Penca type, particularly, were identified as highly resistant. Landraces belonging to the same Portuguese cole group presented a similar range of mean interaction phenotype with the bacterium. Some Portuguese landraces of B. oleracea are potential sources for use in breeding programs for black rot resistance.     

Giemsa N-banding pattern in cabbage and Chinese kale

Summary In cabbage (Brassica oleracea var. capitata) and Chinese kale (B. oleracea alboglabra) four types of N-bands can be distinguished: pericentromeric, telomeric (terminal), intercalary and satellite bands. Typical NOR bands were not observed. The pericentromeric bands appear at the pericentric regions, possibly even at the centromeres of all chromosomes. Telomeric bands are observed on the short arms of chromosomes 1,5 and 6 in cabbage and chromosomes 1 and 5 in Chinese kale. Intercalary bands stained weakly in the long arms of chromosome 3 in cabbage and chromosome 2 in Chinese kale. Satellite bands cover the entire satellites in both Brassica species. The N-banding pattern is very similar in appearance to the C-banding pattern in both species and much more convenient to apply.     

Groups of bread wheat landraces in Austrian alps

Summary Using 49 morphological characteristics sixty-six accessions originating from 15 populations of bread wheat, together with 8 selections from landraces and 5 improved varieties were classified in five groups: group 1: Alpiner Bartwizen (including Hausbergweizen), Attergauer Bartweizen, which are marked by awned white ears; group 2: Awned Sipbachzeller (and its selection Otterbacher Bartweizen) and marked by awned red ears. This group also includes some awned derivatives of hybrids between group 1 and group 3; group 3: Sipbachzeller wheat, including Innviertler wheat and the selections Ritzlhofer Alt, Achleitner and Wieselburger roter Kolben; group 4: Tassilo and Tassilo-variants, and group 5: Dickkopf (Squarehead) types with lax ear, probably being derivatives of hybrids between group 3 and Dickkopf types.Most populations were contaminated with foreign material. The contamination may have been caused by the farmer who actually mixed varieties, or may have originated on the farmer's field.     

Screening of Portuguese cole landraces (Brassica oleracea L.) with Peronospora parasitica and Plasmodiophora brassicae

Summary Forty-four landraces of Portuguese coles (Brassica oleracea L.), representing different morphotypes, were screened at the cotyledon stage for downy mildew resistance, caused by Peronospora parasitica. Two isolates of the pathogen, PHW 630 and PHW 828, were used in the experiment. The mean disease interaction phenotype varied among the landraces. Overall, the Portuguese coles have shown resistance to both isolates, particularly to isolate PHW 828. Some landraces were identified with differential reaction to the two P. parasitica isolates. Some of the Portuguese coles are, therefore, good sources of resistance genes to P. parasitica, and could be used in breeding programs or in the development of a downy mildew host differential set. Among the morphotypes tested, Couve Algarvia (ISA 207), Couve Galega (ISA 243 and 187) and Couve Glória de Portugal (ISA 84) have presented the highest resistance interaction. For the development of host differential sets, the landraces ISA 2 (Penca de Mirandela), ISA 35 (Couve de Valhascos) and ISA 600 (Penca Espanhola) could be further selected for the differentiation of P. parasitica isolates. They are resistant to PHW 828 and susceptible to PHW 643.The same morphotypes and landraces were also screened at the seedling stage for resistance to clubroot, caused by Plasmodiophora brassicae Woron.. Although some variation for resistance could be noticed in some the landraces tested, mainly Galega kale types, none of them presented a sufficient level of resistance as to be directly be useful in breeding for resistance to race 6 of P. brassicae.     

Associations between heat tolerance,water consumption,and morphological characters in Chinese cabbage

Summary Variations with regard to heat tolerance, in terms of heading ability, and water consumption under high temperatures were studied in various Chinese cabbage (Brassica campestris spp. pekinensis Rupr.) varieties. Total water consumption did not differ among entries; however, heat tolerant varieties had greater water uptake than heat sensitive ones at the onset of head formation. Heat tolerant varieties also possessed thicker leaves, higher leaf sap electrical conductivity and chlorophyll content, and lower stomatal number. These characteristics appeared to facilitate water transport to the leaves and reduce transpiration, thus enabling the heat tolerant plants to maintain leaf turgidity during the heading stage at high temperature. Vigorous root growth also seems essential to supply adequate water to the leaves so that they can maintain good turgor at high temperature. Breeding for heat tolerance in Chinese cabbage may be accomplished indirectly by selecting for plants which possess relative thick leaves, high levels of electrolytes, high chlorophyll content, few stomata, and vigorous root growth.Journal paper no. 95 of the Asian Vegetable Research and Development Center(AVRDC).     

Carbon dioxide treatment as an effective aid to the production of selfed seed in kale and Brussels sprouts

Summary The use of carbon dioxide to overcome the self-incompatibility mechanisms in marrow-stem kale and Brussels sprouts (Brassica oleracea L.) is discussed. Results are presented to show the effectiveness of the treatment, and a method is described of applying it as a routine procedure for the production of selfed seed in quantily.     

Evaluation of French Brassica oleracea landraces for resistance to Plasmodiophora brassicae

A total of 240 kale, 38 cabbage and 126 winter cauliflower French landraces from the B. oleracea genepool of INRA were assessed for resistance to clubroot caused by Plasmodiophora brassicaeWoron. Two French isolates of the pathogen (K and SJ) were used in the experiments under controlled conditions. The reaction of the 126 cauliflower accessions to naturally occurring clubroot was also evaluated in field trials. Kales exhibited considerable variation for expression of disease resistance and high levels of resistance were found in several accessions. In this group, single resistant plants were observed in most of the morphological types and from quite different geographical origins. Cabbage accessions were moderately to highly susceptible to both isolates. All cauliflower populations proved to be highly susceptible to K isolate and moderately susceptible to SJ isolate. In field trials, cauliflowers were also severely infected. Two lines selected from a resistant kale population were highly resistant against a large range of pathotypes of the pathogen. These lines presented a sufficient level of resistance to be directly useful in the breeding program in order to develop cauliflower and broccoli hybrids resistant to clubroot. This revised version was published online in July 2006 with corrections to the Cover Date.     

Association of RFLP markers with trait loci affecting clubroot resistance and morphological characters in Brassica oleracea L.

Summary Resistance to Plasmodiophora brassicae Wor. race 7, the causal agent of the disease clubroot, was examined in an F₂ population of a cross between a clubroot resistant broccoli (Brassica oleracea var. italica) and a susceptible cauliflower (B. oleracea var. botrytis). A genetic linkage map was constructed in the same population based on the segregation of 58 dispersed restriction fragment length polymorphism (RFLP) markers. Associations between the inheritance of RFLP marker genotypes and segregation for disease resistance, morphological and maturity characteristics were examined. For each triat examined, several chromosomal regions marked by RFLP probes appeared to contain trait loci, suggesting that each trait was under polygenic control. RFLP marker linkage to a major factor imparting dominance for clubroot resistance from the broccoli parent was observed in this population. Additionally, RFLP marker linkage to an independently segregating factor contributing clubroot resistance from the cauliflower parent was observed, indicating that it should be possible to use RFLP markers to facilitate selection of transgressive segregants having the combined resistance from both parental sources. In some instances, RFLP markers from the same or closely linked chromosomal regions were associated with both clubroot resistance and morphological traits. Analysis of RFLP marker genotypes at linked loci should facilitate the selection of desired disease resistant morphotypes.     

Inheritance of resistance to tipburn in cabbage

Summary Tipburn resistance was identified as being highly but not completely dominant in three nearly isogenic populations of cabbage. Narrow sense heritability estimates of 0.14, 0.34, and 0.49 and broad sense heritability estimates of 0.64, 0.74, and 0.77 were obtained with 2–4 genes controlling resistance. Analysis of resistance was made under conditions of high fertility, especially high N and plentiful moisture and generally high humidity which together resulted in very severe tipburn in susceptible plants.Journal Paper No. 3038 of the New York State Agricultural Experiment Station, Geneva, New York, USA.     

The somatic karyotype of cabbage (Brassica oleracea ssp. capitata)

Summary The individual chromosomes of cabbage are identifiable in nucellar cells found in the ovaries of immature pistils by the combination of their relative length, arm ratios, secondary constrictions, chromatic and achromatic regions and the presence of satellites.     

Competition between cultivars of fodder kale (Brassica oleracea L.) in yield trials with single-row plots

Summary Two experiments were done to evaluate the use of single-row plots for assessing digestible organic-matter (DOM) yield.In the first experiment 29 cultivars were grown in both single-row plots (unguarded) and five-row plots from which only the centre row was harvested (guarded single-row plot). The correlation between yields in the unguarded and guarded plots was very low (r=0.20). Yield was correlated (r=0.89) with cultivar height in the unguarded plots, but not in the guarded plots (r=0.19). Therefore selection for yield in unguarded single-row plots is undesirable and would favour tall kales which are prone to lodging.In the second experiment 16 cultivars were grown in single row-plots guarded by the short cultivar Maris Kestrel, the tall cultivar Vulcan and by the cultivars themselves as control. The correlations between yield in the control plots and yields in the plots guarded with Maris Kestrel and Vulcan were only moderate (r=0.56 and r=0.64 respectively). Therefore the use of a single distinct cultivar to guard single row-plots is undesirable.Selection for DOM yield should therefore be made in multiple-row plots, from which the outer rows are discarded, in order to avoid the undesirable effects of competition.     

Breeding system,taxonomy, and breeding strategy in cauliflower,Brassica oleracea var. botrytis L.)

Summary Cauliflowers representing those maturing in Britain in autumn, winter and spring were assessed for self-compatibility by self-pollen tube growth. A tendency existed for groups taking longer to mature to be more self-incompatible, but a range of incompatibilities was apparent in all groups. These results complement those of other workers.It is argued that despite demonstrable heterosis within many groups of cauliflowers, radical advances are probably best made by selecting self-compatible material from annual × biennial hybrid populations.     

Inheritance of internal pigmentation in green cabbage (Brassica oleracea var. Capitata L.)

Summary Internal anthocyanin pigmentation (IP) in otherwise normally green cabbage occurs in a number of Oregon State University breeding lines. Extracted pigment, tested for spectral absorption and for color reactions with lead acetate and aluminium chloride, was similar but not necessarily identical to pigment extracted from red cabbage cultivar Redman. When IP line R52 was crossed with normal green line C70, the F₁, F₂ and backcross progenies indicated that IP at the intensity found in R52 was determined by a single factor in homozygous condition, with intermediate levels of IP expressed by the heterozygous genotypes. Modifying factors also appear to influence the level of IP. In the cross R52 (IP)×R51 (normal green), expression of IP in the F₁ was much reduced. The F₂ failed to fit the expected 3 IP: 1 green ratio due to an excess of green plants, but instead, closely fit a 9:7 ratio. This may have resulted from incomplete expression of IP because of modifiers, rather than from the effects of a second major gene. An allele at the A (anthocyanin) locus of B. oleracea is tentatively proposed and designated A ^IP or a ^IP pending further identification.Oregon Agricultural Experiment Station Technical Paper No. 4690.     

Inheritance of internode length,plant form,and annual habit in a cross of cabbage and broccoli (Brassica oleracea var. capitata L. and var. italica Plenck.)

Summary When an inbred line of cabbage, Brassica oleracea L. var. capitata L., was crossed with an inbred line of broccoli B. oleraceae var. italica, the F₁ progeny were vigorous late annuals. All F₁ × broccoli backcross plants and 92% of the 3260 F₂ plants were annuals, while 40% of the F₁ × cabbage backcross plants were biennials. Annual habit is thus dominant and controlled by more than a single gene. Number of days to bud appearance in annuals varied continuously, and was primarily additive in inheritance. F₁ data suggested partial dominance for lateness but this was not supported by the F₂. Internode length was also continuous in distribution and primarily additive in inheritance, but with some dominance for short internodes in the F₁. Cabbage head forming ability was recessive and multigenic, with 2% of the F₂ plants forming heads, of which none were of commercial type and about half bolted as annuals. There was a significant chi square association between biennial habit and tendency for cabbage head formation. Clasping habit of terminal leaves was recessive to open leaves, multigenic, and associated with both cabbage heading and biennial habit.Technical Paper 4836, Oregon Agricultural Experiment Station; from an M.S. thesis by the senior author.