Gert Poulsen

Origin and Domestication of Cole Crops (Brassica oleracea L.): Linguistic and Literary Considerations1

Origin and Domestication of Cole Crops (Brassica oleraceaL.): Linguistic and Literary Considerations. Various attempts have been made to locate the area of domestication of Brassica oleracea crops (i.e., cole crops). Contrasting hypotheses suggest either a North Atlantic or a Mediterranean origin. In the absence of archaeological proof, linguistic and literary considerations can offer some insight into this issue. Expressions indicating a deep-rooted knowledge and use of these crops are present in early works of ancient Greek and Latin literature, while no trace of cole crops has been found in documents from ancient Egyptian or other Fertile Crescent civilizations. Most cole crop terminology used in modern European languages can etymologically be traced to ancient Latin or Greek roots, particularly those terms indicating the most obvious morphological feature of the primitive domesticated forms, i.e., the solid upright stem (kaulos, caulis). Celtic tradition is not documented earlier than the Christian era, other than in stone inscriptions, and there is no clear evidence of a “cole tradition” among the Celts. This paper gathers information from the linguistic, literary, and historical points of view that are compatible with the domestication of B. oleracea in the ancient Greek-speaking area of Central and East Mediterranean.RésuméOrigine e domesticazione dei cavoli (Brassica oleracea L.): considerazioni linguistiche e letterarie. Sono stati fatti diversi tentativi di localizzare l’area di domesticazione delle piante coltivate appartenenti alla specie Brassica oleracea (cavoli in senso lato). Sono state proposte ipotesi alternative che propongono un‘origine Nord Atlantica oppure Mediterranea. In mancanza di prove archeologiche, considerazioni linguistiche e letterarie possono offrire qualche indicazione a proposito. Le prime opere scritte delle letterature greca antica e latina contengono espressioni che fanno riferimento ad una consolidata conoscenza e ad un utilizzo ben radicato di queste colture. Viceversa, i documenti scritti lasciati dalle civiltà antiche dell’ Egitto e del Medio Oriente non hanno lasciato tracce riferibili alla presenza di cavoli. La terminologia utilizzata nelle lingue moderne europee per indicare i cavoli può essere fatta risalire etimologicamente a radici latine o greche, in particolare a quei termini che indicano la caratteristica morfologica più evidente che avevano le forme domestiche primitive, cioè il robusto fusto eretto (kaulos, caulis). La tradizione celtica non ha lasciato documenti scritti prima dell’era volgare, se non iscrizioni su pietra, e non e’ stata tramandata alcuna chiara evidenza di una tradizione celtica dell’utilizzo dei cavoli. Questo articolo raccoglie informazioni appartenenti alle sfere linguistica, letteraria e storica, tutte compatibili con una domesticazione di B. oleracea avvenuta nell’area di diffusione della antica lingua greca, cioè nel Mediterraneo Centrale ed Orientale.

AFLP analysis of genetic diversity in leafy kale (Brassica oleracea L. convar. acephala (DC.) Alef.) landraces, cultivars and wild populations in Europe

AFLP markers were used to characterize diversity and asses the genetic structure among 17 accessions of kale landraces, cultivars and wild populations from Europe. The range of average gene diversity in accessions was 0.11–0.27. Several landraces showed higher levels of diversity than the wild populations and one cultivar had the lowest diversity measures. The landraces that were most genetically diverse were from areas where kales are known to be extensively grown, suggesting in situ conservation in these areas as a supplement to storage of seeds in gene banks. An analysis of molecular variance (AMOVA) showed that 62% of the total variation was found within accessions. For most accessions, genetic distance was not related to geographic distance. Similarities among accessions were probably not caused by recent gene flow since they were widely separated geographically; more likely the relationship among them is due to seed dispersal through human interactions. Our results indicate that a kale population found in a natural habitat in Denmark was probably not truly wild but most likely an escape from a cultivated Danish kale that had subsequently become naturalized.

Processes affecting genetic structure and conservation: a case study of wild and cultivated Brassica rapa

When planning optimal conservation strategies for wild and cultivated types of a plant species, a number of influencing biological and environmental factors should be considered from the outset. In the present study Brassica rapa was used to illustrate this: to develop Scandinavian conservation strategies for wild and cultivated B. rapa, DNA-marker analysis was performed on 15 cultivated and 17 wild accessions of B. rapa plus 8 accessions of the cross compatible B. napus. The B. rapa cultivars were bred in Sweden and Finland in 1944–1997 and the wild B. rapa material was collected from Denmark, Sweden and United Kingdom. The B. napus accessions were bred within the last 20 years in the Scandinavian countries. Results were based on scoring of 131 polymorphic ISSR markers in the total plant material. A Bayesian Markov chain Monte Carlo (MCMC) approach implemented in NewHybrids demonstrated a clear distinction of B. rapa and B. napus individuals except for three individuals that seemed to be backcrosses. The backcrossed hybrids descended from two Swedish populations, one wild and one escaped. The overall pattern of genetic variation and structure in B. rapa showed that cultivated and wild B. rapa accessions formed two almost separated clusters. Geographical origin and breeding history of cultivars were reflected in these genetic relationships. In addition, wild populations from Denmark and Sweden seemed to be closely related, except for a Swedish population, which seemingly was an escaped cultivar. The study point to that many processes, e.g. spontaneous introgression, naturalisation, breeding and agricultural practise affected the genetic structure of wild and cultivated B. rapa populations.

AFLP similarities among historic Danish cultivarsof fodder beet (Beta vulgaris L. subsp. vulgarisvar. rapacea Koch)

Dead seeds of a fodder beet cultivar ‘Elvetham’ stored under ambient conditions since 1880 were compared to a homonymous sample preserved in an on-farm situation in Denmark. DNA was isolated from single seeds and successfully applied to Amplified Fragment Length Polymorphism (AFLP) analysis of the accessions. Six primer pairs were used to determine the similarity between the two accessions based on 112 polymorphic bands. Furthermore, similarity among seven cultivars of fodder beets representing the main types used in Scandinavia at the end of the 19th century was determined. This analysis was based on 152 polymorphic bands. Differentiation among the seven cultivars was determined to a mean GST value of 0.438, while GST between the two ‘Elvetham’ accessions was 0.266. A principal coordinate analysis based on jaccards similarity index illustrates that the two ‘Elvetham’ accessions are different from each other. The differentiation is higher than the value found between two separate ‘Eckerndorfer’ accessions. The results indicate that the cultivated accession has changed. Additionally, the value of applying old dead seed material for documentation in gene banks is demonstrated.During the analysis it was found that DNA isolated from seeds and leaves behaved differently in the AFLP process, however, the two fractions assigned to their common accession.

Genetic diversity and population structure of leafy kale and Brassica rupestris Raf. in south Italy

Local varieties of leafy kales (Brassica oleracea L.) are grown in home gardens in Calabria and Sicily for self-consumption, in the same area where the wild relative Brassica rupestris Raf. also grows. With the use of AFLP markers, comparisons were made of the genetic diversity and population structure of ten wild and 22 cultivated populations, as well as of a hybrid population and of four commercial cultivars of different B. oleracea crops. The level of genetic diversity was higher in leafy kales than in wild populations and this diversity was mainly distributed within populations. Wild populations remained distinct from cultivated material. Additionally, most wild populations were distinctively isolated from each other. On the other hand, it was not possible to molecularly distinguish even geographically distant leafy kale populations from each other or from different B. oleracea crops. It was possible to detect inter-crossing between leafy kales and B. rupestris. Findings from this study illustrate the existing level of genetic diversity in the B. oleracea gene pool. Individual populations (either wild or leafy kales) with higher levels of genetic diversity have been identified and suggestions are given for an informed conservation strategy. Domestication hypotheses are also discussed.

Identification and Revival of Low Viability Seed Samples

Seeds stored for a long time may be difficult to germinate under standard conditions and are thus considered not to be viable. By using conductivity test an accession of Brassica rapa L. ssp. rapa with viable seeds was identified among seed material previously declared dead based on traditional filter paper germination tests. The identified accession was germinated by means of long time germination on aseptic agar based growth medium. After transplanting, weaning and vernalisation 0.8% of the seeds could be grown to plants, which flowered and produced seeds.

Domestication, diversity and use of Brassica oleracea L., based on ancient Greek and Latin texts

The domestication process of Brassica oleracea L. has not been fully clarified, either regarding its initial location or the progenitor species involved. Two alternative hypotheses proposed so far point to either a northwest European or a Mediterranean location. Previous studies to clarify the domestication process focused on linguistic aspects and on the earliest occurrences in ancient literature of words referring to B. oleracea. Those studies are here extended to offer a comprehensive account of literary occurrences of the brassica vegetables in ancient Greek and Latin texts, between the VI century B.C.E. and the IV century C.E. This study offers a contribution to ancient ethnobotanical knowledge in the Mediterranean, including agricultural practices and culinary and medicinal uses. It also defines the time when increasing diversity of crop varieties is documented and it adds weight to the hypothesis of a Mediterranean location of the domestication of B. oleracea.

Seed yield and protein content in the Weibullsholm Pisum collection

In Europe, agriculture is highly dependent on imported soybean from South America. Potential alternative sources are protein from peas (Pisum sativum L.) or more local sources like other grain legumes or rapeseed meal (Brassica napus L. subsp. oliefera). These are also good rotation crops. For farmers, protein and yield are key traits. In this study, a dataset containing 37 descriptors and 1222 accessions from a germplasm collection of P. sativum was analyzed. Scatterplot matrixes and tree regression analysis were used to establish the relationship among descriptors and to identify the most important predictors for seed yield and protein content respectively. Number of flowers per plant was shown to be important for seed yield prediction, followed by number of inflorescences per plant and number of pods per plant. In general, a negative correlation between seed protein content and seed yield was detected, but a few accessions that had both high seed yield and high protein content were identified. The results are discussed in relation to crop improvement and the importance of maintaining germplasm collections.