Environmental effects on the distribution of chiasmata among nuclei and bivalents and correlation between bivalents

The control of intranuclear distribution of chiasmata in Delphinium

“…In spite of differences in their inter-nuclear variance, however, all the five plants give indication of a negative inter-group correlation. This shows that significant heterogeneity among inter-nuclear variances does not necessarily determine the direction of correlations as was suggested by the observations of Elliott (1958) on Endymion. The existence of large inter-nuclear variances in several of the plants, on the other hand, suggests the need for extending the analysis to the level of individual cells within a plant.…”

“…More recently Rowlands (1958) has shown that in different plants of Vicia faba, there is a wide range of correlation coefficients, from negative correlations that are highly significant to positive which approach the level of significance. Variable behaviour of this type has also been demonstrated by Elliott (1958) variance with increasing number of chiasmata (text- fig. 3) indicates that at lower levels of chiasma frequency, the inter-bivalent distribution of chiasmata is to a large extent independently determined.…”

The interchromosome distribution of chiasmata in interchange heterozygotes of Delphinium

“…That such variability exists has been pointed out earlier and is shown by the analysis of a number of authors including Rowlands (1958) and Elliot (1958). It is possible that variation in the autonomous fraction may be due to other undefined factors.…”

“…In order to find out whether the different groups of chromosomes showed chiasma formation in an independent or interrelated manner, the analysis of variance described fully by Elliot (1958) has been performed. This analysis makes it possible to divide the total variation with regard to chiasma distribution into three components-two of which are the internuclear variance which measure the variation in the total number of chiasmata among the pollen mother cells of a plant, and the inherent variance which gives a measure of the variation in the distribution of chiasmata between groups of chromosomes within nuclei.…”

Meiotic Studies in <i>Vinca rosea</i> Linn

“…The corre lation of chiasma frequency between the two groups was determined by the method illus trated by Elliot (1958). Since all the eight bivalents in Vinca rosea cannot be distinguished from one another, the internuclear and intranuclear variances were calculated by evaluating the variation in the two groups of bivalents.…”