SOME EXPERIMENTAL OBSERVATIONS ON THE CLONE STRUCTURE OF A NATURAL POPULATION OF FESTUCA RUBRA L.

Abstract

It is confirmed that a worker observing for a season a pair of spaced plants of Festuca rubra growing alongside each other in an experimental garden can conclude with considerable reliability whether or not the two plants are of the same genotype. Out of over 3000 such comparisons made only nineteen proved to be difficult and, even in these cases, the opinion formed after the season's observations proved to be right sixteen times. Sampling patterns more complicated than simple paired isolates are more productive of information and are not too difficult for observation so long as the number of isolates being compared at a time is less than about eight to twelve. The more complicated patterns are more difficult to collect, especially where species cover is low or variable and, for this reason, their use can lead to bias in the observations. The clonal constitution of the population is not uniform over the site. There is a tendency for F. rubra to be more abundant in those parts of the site where the local population is dominated numerically by a single clone. The element of non‐randomness introduced by any sampling method which utilizes isolates from discrete parts of the site is likely to generate serious bias in the results. Small portions of the site are colonized by several different clones intermixed with each other—the mean number of clones present in a 15 × 15 cm turf being 5.2. The chances of two isolates from the population being of the same genotype fall off with distance from about 42% at 2.5 cm apart to 1% at 320 cm. By contrast with a population described earlier, this population is made up of very many clones, several of them being extensively reduplicated, but none of them so extensively as to numerically dominate the population. There are many differences between the two populations in ecology and probably in history but the causes of the different constitutions were not investigated. Copyright © 1969, Wiley Blackwell. All rights reserved