Диагностические признаки представителей рода Robinia L. по генеративным показателям в интродукционных популяциях

Abstract

Promising forms of various species of the genus Robinia L., which are of great interest for enriching the gene pool of cultivated woody plants in arid regions. Genetic diversity is an important condition for the ability of populations to adapt to environmental changes. The higher the genetic heterogeneity, the greater the ability of the species to adapt to changing environmental conditions. The aim of the research is to inventory the species and form diversity of introduced Robinia populations and develop their diagnostic features based on the study of the structure and development of generative organs. The objects of research were introduced populations of different species and forms of the genus Robinia: R. adhesive-R. viscosa Vent.; R. neomexicana – R. neomexicana A. Gray; R. liegacy – R. pseudoacacia L., which grow in a cluster collectible parts FNTS Agroecology Russian Academy of Sciences, cadastre №34:34:000000:122, 34:34:060061:10. The results of the inventory collection funds has allowed to establish that the parental lines FNTS Agroecology wounds there are forms Robinia pseudoacacia and Robinia neomexicana, differing significantly from the typical representatives (Robinia neomexicana: R. neomexicana f. pale pink, R. neomexicana f. pale purple; Robinia pseudoacacia R. pseudoacacia f. postseconda). They are represented by large introduced populations (age 15 years), maintaining the number of which is due to natural vegetative and generative methods of reproduction. Analysis of natural distribution areas revealed that The most polymorphic species is considered to be Robinia neomexicana Grey (Robinia neomexicana Grey). In Russia it is often cultivated and is described, entitled Robinia lush (R. luxurians (Dieck) S. K. Schneid.). Developed diagnostic features characteristic of the selected forms and typical representatives of different species of the genus Robinia. Among them: the color of the Corolla and calyx, calyx structure, pubescence, the presence of a wing on the fruit, fruit size, generative axis of inflorescences, the average size of inflorescences, the number of inflorescences on the shoot, the duration of flowering terms. An important diagnostic feature in the identification of species of the genus Robinia is the structure of the calyx. The measurements showed that only Robinia pseudoacacia has fully fused upper sepals (adaxial sinus is not more than 0.3-0.6 mm). Cups R. neomexicana and R. viscosa and even R. pseudoacacia f. postseconda sometimes have distinct adaxial sinus to 4.5 mm. the Size of the flowers and the average number of flowers per inflorescence differs slightly. So, the average number of flowers varies from 20.5 units (Robinia neomexicana) to 22.3 (R. neomexicana f. pale purple). The sizes of inflorescences and the number of inflorescences on a shoot (during spring mass flowering) significantly differ. Fruits of R. viscosa Vent., R. neomexicana A. Gray (including forms) have side seams of equal width (wing absent). In addition, the fruits of R. pseudoacacia and its late-flowering form are always glabrous, the fruits of R. neomexicana A. Gray and its forms are bristly, and the fruits of R. viscosa Vent. - glandular-bristly (sticky in the immature state). The features of the structure and development of generative organs are analyzed, the seed productivity and fruit productivity of various species and forms of the genus Robinia are determined. It was revealed that the highest generative potential in arid climate has R. pseudoacacia and its forms, and the lowest – representatives of R. viscosa. A high percentage of set seeds (number of ovules/number of set seeds) was observed in R. pseudoacacia and its late-flowering form (more than 70%). Representatives of R. viscosa Vent had a low percentage of set seeds. and R. neomexicana A. Gray f. pale purple. The setability of seeds of typical representatives of R. neomexicana A. Gray was more than 60%. It was revealed that the most abundant and long - flowering species in arid conditions of the Lower Volga region is R. viscosa Vent. Widespread in the culture were two species: R. pseudoacacia L. and R. viscosa Vent. Robinia pseudoacacia, which has the largest range of natural distribution, has a wide range of adaptive capabilities and is easier to adapt to new conditions of existence in the process of introduction. This advantage allowed R. pseudoacacia to receive the widest distribution in culture not only in North America, but also in Russia. The second kind is R. viscosa Vent. it has the narrowest area of natural distribution, however, high decorative properties and, as a consequence, the active use of this species in the objects of gardening, allowed to significantly expand the area of its secondary distribution in North America, Europe and southern regions of Russia. Clustering of the main diagnostic signs revealed the belonging of the selected forms to a particular species, which is confirmed by the results of correlation analysis.