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Page 25 · DO #4883 · 231_Rogers_Bx8FF15_r
- Collection
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David James Rogers (1918–2007) papers
- Item/Folder
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Manihot - Gainesville Talk, 1960 or 1961
- Digital Object
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DO #4883,
page 25
- Collection-level dates
- 1948–1977
Page transcription
environment is quite striking as I begin to compare the plants of each locality.
In Costa Rica, through the efforts of Dr. Jorge Leon, most of the clones occurring in that country had already been assembled in museum plots at Turrialba. By cooperation with various inter-American agricultural missions, and through departments of agriculture of several South American and Far Eastern countries, we were able to establish Turrialba as a center for bringing together clones from all over the world.
By June of this year, the two plantings of local clones in Jamaica were ready for sampling. The methods of sampling are essentially those which Anderson describes for his "inclusive herbarium" specimen, in which a single herbarium sheet contains data for a population rather than a single plant. Since there was no opportunity to make evaluations of characteristics of taxonomic importance previously, it was necessary to keep a record of as many characteristics as could be determined. Some characters were more obvious, but others have not yet appeared as important.
The variations amongst plants of a single clone were recorded, and if possible, coded by number. (Registrars at most schools have IBM machines available, and not working at all times.) As each clone was studied, one average plant was selected and photographed against a calibrated board, once at a standard distance of 5 meters for the habit photograph, and once at 2 meters for a detail of the leaf, root and stem sections. An herbarium specimen of the leaf, the apex of the vegetative shoot, sections of stem and root, and when possible, a flowering or fruiting branch was made. For each specimen, coloration, state of maturity of root, etc., were recorded. Any ripe seeds were collected to complete the record. At time of sampling, if roots were mature, a sample was sent to the agricultural chemist of the Jamaican department for analysis of HCN and carbohydrate content.
With the help of two field hands, and one of the officers of the agronomy division, it was possible to complete the various parts of the sampling