Biological resources of the Fabaceae family in the Cretaceous south of Russia as a source of starting material for drought-resistance selection

Abstract

Aim: The south of the Central Russian Upland is a region with particular natural landscape-climatic conditions, the large anthropogenic load, and the intensive development of agricultural farming. A feature of the area is the high content of calcium carbonate in the soil, which reduces the total biological productivity of biocenoses in general and of agrophytocenoses in particular. Materials and Methods: The aim of this work is the study of biological resources of the genera Medicago and Trifolium species in Cretaceous South of the Central Russian Upland as the most valuable in genetic and economic terms. They, in most cases, determine the amount of biological capacity of erosion agro-landscapes. Objects of the study are wild cenopopulations alfalfa Medicago varia Mart. and white clover Trifolium repens L. In the midst of reduced interspecific and intraspecific competition on the detrital fans, introgressive hybridization and microevolutionary changes in cenopopulations occur. The founder effect is in evidence; it is the accumulation of recessive genes, forming the reserve for natural selection and processes of intermutations. The adaptation processes in cenopopulations are aimed to the preservation of forms having morphological and biological qualities, similar to the properties of endemic calciphilous vegetation. Results and Discussion: The studying of adaptive microevolutionary processes occurring in gullies and gully complexes allowed the authors to develop the concept of formation on the Cretaceous South of the Central Russian Upland the secondary (anthropogenic) microgene center for the formation of commensal species of these genera, as Medicago, Trifolium, and others. For the selection of valuable forms under natural conditions, a system of integrated biological indicators is developed: Rhizospheric index and iron index are closely correlated with the parameter of seed productivity and resistance (r = 0.871–0.921) selection by which provides drought-resistance progeny and competitive advantages in mixed crops on calcareous soils. The involvement of genetic resources of wild cenopopulations of alfalfa and clover as starting material is advantageously carried out by methods of recurrent selection. This method obtained a number of new varieties of clover and alfalfa, which have a high drought-resistance, stable seed yield, and wide ecological amplitude. Conclusion: Selections with different characteristics of the new varieties of alfalfa and clover are already included in the future schemes of recurrent selection to obtain new, more high-yielding forms.