Test for allelism of spontaneous mutants of maize

As a result of our previous studies which were presented in detail in the book, V. E. Micu, "The Genetical Studies of Maize," published in 1981, a large number of spontaneous mutants of maize were collected and partially studied. The genetic analysis of this material was continued. During the last 3 years, more than 350 mutants, including the following classes--kernel form and texture, upright leaves, brown midrib, dwarfism, ramosa ear and male sterility--were tested. For the endosperm, dwarf and ramosa mutants, a phenotypical classification was previously conducted, and the nonidentified sources were crossed first with the similar genetic markers. This procedure helped us to reduce the number of crosses and to raise the effectiveness of tests.

Among 43 floury endosperm mutants, 4 new sources of o2 and 2 of fl2 were identified. Besides, another 9 sources gave a positive test with fl2 marker. However, taking into account the more complicated inheritance of fl2 and availability of cfl2 (A. Paliy, Genetica 11:5-7, 1975) the identification of these sources cannot be considered complete.

Two phenotypically different groups of dwarf mutants were studied: one including 30 sources of brachytic, and the other 16 sources of dwarf type. Most of the tested mutants turned out to be non-allelic to markers, but nevertheless many new sources of br1, br2 and d1 (Table 1) were identified. Among the ramosa ear mutants that we have in our collection, ra1 phenotypes predominate, and that was confirmed by genetic analysis. New sources of male sterility genes ms2, ms9, ms10 and ms13 were identified. The sources of sterility were also tested with other markers, but the test turned out to be negative.

In all phenotypical groups which were studied, many mutants still remained unidentified. It is possible that this material contains unknown or rare genotypes.

Table 1. The list of tested identified mutants.

V. E. Micu, P. M. Botnarenco, T. A. Solonenco, E. C. Partas and N. S. Frunze

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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