corn

Dihaploid lines, or lines obtained on the basis of doubled haploids, are a valuable material for the creation of high-heterosis corn hybrids. The most eff ective method of evaluating the starting material when selecting parental couples for obtaining hybrids is diallell analysis. The article presents the results of the analysis of indicators of 6 dihaploid corn lines and 30 simple corn hybrids of the dialle scheme. The combinative ability of lines along the stem length, the cob attachment height, and the panicle length was studied.

The article presents the results of studying the combination ability of new dihaploid maize lines created by diploidization of haploid plants obtained using a haploinducer line. The experiment involved simple hybrids (30 combinations) obtained according to the complete diallel scheme of 6 homozygous lines. The eff ects of GCA and variance of SCA lines, as well as the components of genetic variance in terms of the main morphometric parameters of the plant (stem length, ear height, panicle length, stem diameter, plant leaf surface area) were revealed.

The article is focused on studying of cytoembryological preconditions of polyembryony in the not pollinated ovary of the apomictic maize line АТ-1 under in vitro and in vivo conditions. For an assessment of a nutrient medium role in polyembryony induction a relative analysis of the embryo sacs in cultivated in vitro and native plants ovaries has been lead. Dynamics of formation in them an apomictic twin proem- bryo is traced.

Many modern selection technologies are based on the use of haploid plants as a starting material. The spontaneous frequency of haploid development is very low (0.01–0.1%). In this regard, the creation of plant forms with increased frequency of parthenogenesis is important. The collection of corn lines with an increased frequency of haploid plants in the progeny was created at the Department of Genetics of the Saratov State University. High costs are required for maintain of a plant collections in the field.