Brachytic maize, especially br2, has been widely studied with the purpose of developing brachytic hybrids, but they have been significantly lower in yield than normal. In order to determine the possibility of using br2 lines in breeding programs three versions of hybrids were developed: normal, Br2 Br2; heterozygous, Br2 br2; and brachytic, br2 br2. During 1979-1982, 20 hybrids in the three versions were evaluated for 11 morphological, biological and economical characters.
The results indicate that homozygosis for recessive alleles of br2 exerts an effect on some morphological characters (see Table). First of all the plant height and the ear height of br2 br2 are considerably reduced, which has been proven before. Morphological characters of heterozygous versions in general did not differ from normal, though in some hybrids significant differences were observed. Brachytic versions were most resistant to lodging and to common smut (Ustilago maydis); normal counterparts were less resistant and the heterozygous versions were intermediate. Vegetation periods of br2 versions were longer than those of normal. Brachytic versions yielded significantly lower than normal, which is in accordance with the results of other researchers, but the heterozygous versions considerably surpassed the normal and brachytic counterparts.
The data we have obtained demonstrate the possibility of using brachytic lines and hybrids (homozygous br2) as crossing components with normal forms with the purpose of developing more productive and more lodging-resistant maize hybrids.
V. E. Micu and T. A. Solonenko
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