J. G. Hawkes

The Biology and taxonomy of the Solanaceae

The Biology and taxonomy of the Solanaceae , The Biology and taxonomy of the Solanaceae , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Insect resistance in potatoes: sources, evolutionary relationships, morphological and chemical defenses, and ecogeographical associations.

SummaryThe past 25 years, 1686 potato accessions, representing 100 species in the genus Solanum L., subgenus Potatoe, section Petota, were evaluated for field resistance to one or more of the following insect pests: green peach aphid, Myzus persicae (Sulzer); potato aphid, Macrosiphum euphorbiae (Thomas); Colorado potato beetle, Leptinotarsa decemlineata (Say); potato flea beetle, Epitrix cucumeris (Harris); and potato leafhopper, Empoasca fabae (Harris). Accessions highly resistant to green peach aphid were identified within 36 species, to potato aphid within 24 species, to Colorado potato beetle within 10 species, to potato flea beetle within 25 species, and to potato leafhopper within 39 species. Resistance levels were characteristic within Solanum species. Insect resistance appears to be a primitive trait in wild potatoes. Susceptibility was most common in the primitive and cultivated Tuberosa. Insect resistance was also characteristic of the most advanced species. The glycoalkaloid tomatine was associated with field resistance to Colorado potato beetle and potato leafhopper. Other glycoalkaloids were not associated with field resistance at the species level. Dense hairs were associated with resistance to green peach aphid, potato flea beetle, and potato leafhopper. Glandular trichomes were associated with field resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Significant correlations between insect score and altitude of original collection were observed in six of thirteen species. Species from hot and arid areas were associated with resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Species from cool or moist areas tended to be resistant to potato aphid.

Complementary conservation strategies

The challenge facing the world’s biological and conservation scientists is threefold: to classify the existing biological diversity; to halt the rate of ecosystem, habitat, species and genetic loss; and to feed the ever increasing human population. It is generally agreed that a catastrophic loss of plant genetic diversity is occurring at this moment: species, gene combinations and alleles are being lost for ever and this process of genetic erosion is likely to become even more grave in the future. The conservation of plant diversity is of critical importance, because of the direct benefits to humans that can arise from its exploitation in new agricultural and horticultural crops, the development of medicinal drugs and the pivotal role played by plants in the functioning of all natural ecosystems. The economic, political and social consequences that would result from a steady loss of plant diversity combined with rapid population growth is likely to be devastating if unchecked. The importance of these issues to humankind is underlined in Article 1 of the objectives of the Convention on Biological Diversity (UNCED, 1992): The objectives of this convention ... are the conservation of biological diversity, the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilisation of genetic resources ...

The Ex Situ conservation of plant genetic resources

Preface. Acronyms and Abbreviations. Figures, Plates, Tables and Appendices. 1. The Genetic Resources of Plants and Their Value to Mankind. 2. Evolution of Plants Under Domestication. 3. The Plant Genetic Resources Conservation Movement. 4. Preparing to Collect for ex situ Conservation. 5. Exploration and Field Collection. 6. Seed Gene Bank Conservation. 7. Field Gene Banks, Botanic Gardens in vitro, DNA and Pollen Conservation. 8. World ex situ Collections of Germplasm. 9. Community-Based Conservation. 10. Plant Genetic Resource Utilization. 11. Genetic Conservation Information Management. 12. Conservation Case Studies. 13. The Future of ex situ Conservation. References. Appendices. Index.

Plant genetic resources of Ethiopia.

Part I. General Introduction: 1. An Ethiopian perspective on conservation and utilization of plant genetic resources M. Worede Part II. The Ethiopian Centre of Diversity: 2. The Ethiopian gene centre and its genetic diversity J. M. M. Engels and J. G. Hawkes 3. Crops with wild relatives found in Ethiopia S. B. Edwards 4. Diversity of the Ethiopian flora T. Berhan and G. Egziabher 5. Forest genetic resources of Ethiopia J. De Vletter 6. Plants as a primary source of drugs in the traditional health practices of Ethiopia D. Abebe and E. Hagos 7. Traditional aromatic and perfume plants in Central Ethiopia E. Goettsch 8. Spice germplasm in Ethiopia E. Goettsch 9. A diversity study in Ethiopian barley J. M. M. Engles 10. Sorghum history in relation to Ethiopia H. Doggett 11. Prehistoric Ethiopia and India: contacts through sorghum and millet genetic resources K. L. Mehra 12. Ethiopian fungal gene resources and the need for their conservation D. J. Bhat and E. Bekele 13. Konso agriculture and its plant genetic resources J. M. M. Engels and E. Goettsch Part III. Germplasm Collection and Conservation in Ethiopia: 14. Theory and practice of collecting germplasm in a centre of diversity J. G. Hawkes 15. A decade of germplasm exploration and collection activities by the Plant Genetic Resources Centre/Ethiopia (PGRC/E) A. Demissi 16. Collection of Ethiopian forage germplasm at the International Livestock Centre for Africa J. Hanson and S. Mengistu 17. Germplasm conservation at the PGRC/E R. Feyissa 18. The strategic area seed reserve project in Ethiopia W. Woldemariam and F. Pinto 19. Documentation at PGRC/E E. Sendek and J. M. M. Engels Part IV. Evaluation and Utilization of Ethiopian Genetic Resources: 20. Germplasm evaluation with special reference to the role of taxonomy in genebanks J. G. Hawkes 21. Crop germplasm.

Significance of wild species and primitive forms for potato breeding

AbstractThree stages in the history of the utilization of wild potatoes are outlined, and it is suggested that we are now entering on a fourth stage, typified by a fuller international co-operation than has hitherto been possible.The availability of useful genes is considered in the light of our knowledge of the crossability and evolutionary relationships of potato species. Breeding mechanisms in species at various levels of ploidy are shown to play an important part in speciation, and the significant role of asexual reproduction in potatoes is discussed.The geographical localization of most genes carrying resistance to Phytophthora, viruses, Heterodera, Leptinotarsa and frost is discussed. Certain explanations to account for this localization are put forward.ZusammenfassungBedeutung der Wildkartoffeln und Primitivformen für die Kartoffelzüchtung In der Geschichte der Verwertung der Wildkartoffeln werden drei Stufen abgezeichnet und die Ansicht vertreten, daß wir eben in eine vierte eintreten, welch durch vollere internationale Zusammenarbeit als bisher möglich gewesen ist, charakterisiert wird.Die Tatsache, daß wertvolle Gene zur Verfügung stehen, wird im Lichte unserer Kenntnisse der Kreuzbarkeit und der Entwicklungsbeziehungen von Kartoffelarten betrachtet.Es wird aufgezeigt, daß Reproduktionsmechanismen in Arten auf verschiedenen Stufen der Ploidie eine wichtige Rolle in der Artzüchtung spielen, ferner wird die wichtige Rolle asexueller Reproduktion in Kartoffeln behandelt.Die geographische Lokalisierung der meisten Genen, die gegen Phytophthora, Viren, Heterodera, Leptinotarsa und Frost resistent sind, ist hier behandelt. Erklärungen für diese Lokalisierung werden hier vorgeschlagen.ZusammenfassungIn der Geschichte der Verwertung der Wildkartoffeln werden drei Stufen abgezeichnet und die Ansicht vertreten, daß wir eben in eine vierte eintreten, welche durch vollere internationale Zusammenarbeit als bisher möglich gewesen ist, charakterisiert wird.Die Tatsache, daß wertvolle Gene zur Verfügung stehen, wird im Lichte unserer Kenntnisse der Kreuzbarkeit und der Entwicklungsbeziehungen von Kartoffelarten betrachtet.Es wird aufgezeigt, daß Reproduktionsmechanismen in Arten auf verschiedenen Stufen der Ploidie eine wichtige Rolle in der Artzüchtung spielen, ferner wird die wichtige Rolle asexueller Reproduktion in Kartoffeln behandelt.Die geographische Lokalisierung der meisten Genen, die gegen Phytophthora, Viren, Heterodera, Leptinotarsa und Frost resistent sind, ist hier behandelt. Erklärungen für diese Lokalisierung werden hier vorgeschlagen.SamenvattingDrie stadia in de geschiedenis van het gebruik van wilde aardappelsoorten en primitieve aardappelrassen worden genoemd. Omstreeks 100 jaar geleden waren nieuwe rassen nodig ter bestrijding van degeneratieziekten, terwijl omstreeks 1909 het wilde materiaal voor het kweken op ziekteresistentie ter hand werd genomen. Het 3e stadium begon in 1925 toen de eerste grote expeditie werd gehouden om materiaal te verzamelen voor een onderzoek naar de genetische variatie van de aardappelsoorten. Thans is men gekomen in het 4e stadium, nl. een nauwere internationale samenwerking dan tot nu toe mogelijk was.Schrijver geeft een overzicht van de perspectieven voor het kweken op resistentie tegen Phytophthora, virusziekten, Heterodera, coloradokever en vorst. Het is gebleken dat bepaalde genen in bepaalde gebieden voorkomen (geographical localization).

History of the potato

The time and place of origin of cultivated plants and their subsequent evolution under domestication have caught the imagination of botanists and agricultural scientists from at least the early days of the last century. The studies of de Candolle, Vavilov and others have shown the need for a synthesis of information from such diverse fields as cytogenetics, history, linguistics, botany and archaeology to help trace the complete pattern of evolution of our ancient crops, many of which were already being cultivated some nine or ten thousand years ago.

Conservation of plant genetic resources

Higher yields, better quality, easier harvesting, resistance to pests and diseases are a few of the many existing reasons why improved crop varieties are required. Other—as yet unsuspected—needs can arise in the future as a consequence of the rapidly changing patterns of agriculture. Under these circumstances, plant breeders require large reservoirs of genetic material. The management and exploitation of such resources are only now beginning to receive the attention they deserve.

The early history of the potato in Europe

SummaryAlthough many crops were brought to Europe by Columbus and others soon after the discovery of the New World in 1492, the potato arrived much later. This is because it is a cool-temperate crop of the high Andes of South America, and these were not discovered by the Spaniards until 1532. Potatoes were not recorded in the literature until 1537 in what is now Colombia, and did not feature in published works until 1552. No actual account has yet been discovered (and very probably does not exist) of potatoes being brought to Europe. All we can do is to record, where possible, their earliest presence there.One of the problems in such a study is to recognize in the literature whether the Solanum tuberosum potato or the Ipomoea batatas sweet potato is under discussion, or whether they are being confused with each other. Even the word ‘potato’ known in Spanish as ‘patata’ is obviously derived from ‘batata’ yet the early Spanish authors seem always to have clearly distinguished between them. We ourselves checked the Seville archive records to make sure that the Solanum potato records of 1573 and 1576 were correct, and indeed we found that they were. The earlier English records, apart from that of Gerard, seem to have referred to the Ipomoea sweet potato.We report in this paper even earlier records from the Canary Isles, where ‘patatas’ and ‘batatas’ are clearly distinguished, and the South American word ‘papa’ for Solanum tuberosum is also used sometimes (never, however, in continental Spain). Barrels of potatoes (‘patatas’) were exported from Gran Canaria to Antwerp in November 1567 and from Tenerife via Gran Canaria to Rouen in 1574. Thus the potato was obviously being grown as a crop in Gran Canaria and Tenerife in 1567 and 1574, respectively. We can therefore assume with some certainty that it would have needed some five years to bulk it up sufficiently as an export crop, and hence might well have been introduced in about 1562. This is only ten years after the first published account in 1552 by López de Gómara, and only thirty years after its presumed first sighting in Peru by Pizarro in 1532. It also seems to point towards the introduction of potatoes from South America into the Canary Isles, and not, as we had previously assumed, directly into continental Spain.

Introgression in certain wild potato species

It is pointed out that no variations in the cultivated potato have hitherto been interpreted as due to introgression, even though the necessary prerequisites for introgressive hybridization are often present. Certain geographical regularities in respect of disease resistance genes may be interpretable as due to natural selection of random mutations rather than to a flow of genes from a resistant species into a susceptible one.Introgression of genes from the diploid species Solanum stenotomum to the tetraploid S. tuberosum and vice versa seems to be very probable, though it is difficult to obtain exact proof of this.The evidence for introgressive hybridization between the Argentine wild potato species S. chacoense and S. microdontum is rather better. From measurements of a number of distinct characters in a wide range of specimens of S. chacoense it seems fairly certain that introgression is taking place in the mountains of N.W. Argentina. In consequence, S. chacoense, which was originally a low-altitude species, adapted to open places in the Argentine plains, has been able, as a result of contamination with germ-plasm from S. microdontum, to extend considerably its ecotypic range. Thus it now colonizes areas and extends into altitudes where the pure species is probably quite unable to penetrate.