The response of maize lines to the Paraguay type of CMS

Abstract. The development of cytosterile maize hybrids in Russia is a necessary condition for their wide implementation into production. To develop such hybrids, it’s greatly relevant to be aware how the lines react to sterile cytoplasm. The study was carried out at the Agricultural Research Center “Donskoy” (“ARC “Donskoy”) in 2010–2021. The purpose of the current study was to classify the new self-pollinated maize lines according to the composition of the fertility-restoring genes of the Paraguay (C) type of CMS, to optimize the number of analyzing test-crosses. Methods. As initial material there have been used 45 new self-pollinated maize lines and 8 sources of sterility with different genetic structure. The method of complete top-crosses there have been identified 360 maize hybrids, used for estimation of the new lines’ reaction. Results. According to the study results, the sterility-fixing lines KV 204, SP 286, DS 255, SP 207, DS 180, which had no fertility-restoring genes in the dominant state, belonged to the I class. As the natural complete constant fertility-restorers there has been recommended to use the lines of the VIII class KV 498, KV 272, KV 7/07, SP 357, RD 261, DS 295, SP 210, SP 197, DS 177, DS 188, having all three dominant genes Rf4, Rf5, Rf6 in the genotype. The incomplete sterility-fixing lines included the lines of the II–IV classes (KV 3, RD 245, SP 198, etc.). The incomplete fertility-restoring lines were the lines of the V–VII classes (KV 469, RD 331, KV 276, etc.). There has been found out that the most common lines were the lines of the V (24.4%) and VIII (22.3 %) classes. The scientific novelty of the study was an optimal number and genetic structure of the analyzers WF 9c of the V class, Lc of the VI class and W 401c of the VII class, which are necessary for crossings and allow identifying lines according to the fertility-restoring genes.