[Selective and genetic aspects of using cytoplasmic male sterility of corn]
2007
Gorbacheva, A.G.
The study was performed in the conditions of the Krasnodar and Stavropol Krais. Corn lines, 250 in number, were analyzed by reduction of pollen fertility. In M-type of CMS complete sterility fixers are 84.8% of lines, complete sterility reducers – 4.0%, incomplete fertility fixers – 11.2% of lines. The similar indices for C-type are 54.0; 32.0 and 14.0%; for SD-type – 85.6; 4.0 and 10.4%, respectively. An effective method of evaluating the resistance of corn to south helminthosporiosis of Texas race has been developed. The ears of T-cytoplasm analogs were severely affected with disease (54.7.4 points), and the N, M and C-types cytoplasm analogs – weakly. The similarity of SD-type of CMS with M-type was found. The reduction of fertility in C-type cytoplasm is controlled with genes Rf4, Rf5 and Rf6. Late anther crackling typical for this sterility type is controlled with additional recessive genes which are localized on the cytoplasm of maternal form. As is found, the type of cytoplasm has a true influence on the plant height, ear fixing height and head pedicle length. Some differences were found in specific combination ability of original lines and their sterile analogs. To avoid negative influence of cytoplasm on corn crop, ready analogs but not original lines are recommended to include in test crosses. The new type of cytoplasm ML, S, R, L, CA relating to CMS M-group may be used in practical seed production of hybrid corn. As maternal forms to produce new hybrids it is recommended to use early ripe varieties Madonna M, Siren M, Lider C, PPG 103 M, Djuna C, Azalia SD. This will allow to develop profitable seed breeding even in the areas with limited vegetation period.
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