II.4. A diallel analysis of the expression of "irregulare" condition in barley spikes.
K. Takeda and W. Saito, Institute for Agricultural and Biological Sciences, Okayama University, Kurashiki, Okayama, Japan.
There is a group of cultivars classified by Aberg and Wiebe as "irregulare (labile)", whose lateral florets reduced to rachilla in some cases and these located irregularly on the spike. This type of barley is known to be distributed mainly in Ethiopia. Several researchers have reported that the "irregulare" condition is controlled by a gene lab which is hypostatic to the gene V (2-rowed). So far as the experimental results hitherto obtained, no clear evidence to support a single gene control of the "irregulare" condition has ever been indicated. Moreover, the degree of expression of "irregulare" condition, which is indicated here as percentage of lacking laterals, shows remarkable variation among varieties. Therefore, the character "irregulare" must be analyzed quantitatively as well as qualitatively. We have analyzed the inheritance of varietal variation of "irregulare" condition using 10 x 10 diallel cross (Table 1). For the statistical analysis the percentage of lacking laterals was transformed into the degree of angle.
Table 1. Materials used in the diallel analysis and their expression of irregulare.
The following features have been revealed by an analysis of variance
of the diallel table:
1. Additive as well as dominance effect of genes is significant.
2. Reciprocals show no difference.
3. The dominance deviations of the genes are predominantly in one direction,
and high expression is recessive.
4. Number of effective factor pairs is more than eleven.
5. The narrow and broad sense heritabilities are as high as 82% and
85%, respectively.
Vr vs. Wr analysis (Figure 1) proves the absence of nonallelic interaction, independent distribution of the genes among the parents, and incomplete dominance of the genes concerning the expression of "irregulare" spikes.
Correlation between Wr+Vr and the degree of expression of common parents (Figure 2) indicates that those varieties with high expression involve many recessive genes, and this coincides with the result of analysis of variance mentioned earlier.
Figure 1. Regression of Wr on Vr for expression of irregulare.
Figure 2. Correlation between (Wr+Vr) and expression
of common parents (in degree of angle).
