The studies were intended to clarify the effects of selection in red pepper breeding. Fourty F₄ lines of a red pepper cross were used as the materials. Five characters, namely, stem length, stem diameter, riped fruit weight, riped fresh fruit number and riped dry fruit weight were measured in an individual plant basis.
The results obtained are summarized as follows:
1. Phenotypic and genotypic covariances, and phenotypic variances were calculated to maintain the selection indexes as shown in Table 1.
2. Many selection indexes which contain several characters in calculation were calculated with various selection indexes. These results suggest that selection index technique is useful in plant breeding. In reality, however, as the selection index varies with population and environment in which the population is located. Inspite of the expected usefulness of selection index technique in plant breeding, unsolved problems such as the expense, time and labor involved in calculating the selection index are remain. For these reasons it was realized that the selection index for the selection should be calculated on the basis of the data of some 2-4 characters. Inspite of the selection index technique is useful in grain crops, such as corn and soybeans, it was recognized that, in the breeding of red pepper plant, especially, the selection of desirable lines for pepper powder production should be based on some other characters such as fruit shape after drying an drying ratio duration from harvest to drying rather than on selection score after selection in dex calculating.
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