Закріплення гетерозису серед нащадків у Arabidopsis Thaliana (L.) Heynh. та інших самозапильних рослин

Abstract

An important task of plant breeding is to develop methods of fixing heterosis in the second and subsequent generations. In many cross-pollination crops, in particular sunflower, corn, have to lead complex seed production. For self-pollinating plants of wheat, barley, oats, the use of the effect of heterosis is limited to a low percentage of tying of grains, a weak seed multiplication factor. The solution of the problem of preserving heterosis in plants in a number of generations would make it possible to simplify and reduce the cost of practical use in plant growing. Success in addressing the issue of fixing the effect of heterosis is the use of Arabidopsis thaliana (L.) Heynh. as a model plant. Studies on model objects are always considered to be advanced. They allow us to develop new genetic approaches that can later be used at other sites. The aim of the present study was to study the possibility of the emergence and fixation of heterosis in subsequent generations in self-pollinating plants by crossing the races of Col-O and La-0 Arabidopsis thalian a. The material for research was the plants Arabidopsis thaliana ecotype (race) Columbia (Col-O) and Landsberg (La-0). The plants were grown in a soil culture laboratory in a mixture of soil, sand and peat in a ratio of 4: 2: 1. Castration and forced hybridization were carried out under a microscope. Genetic analysis of plant inheritance was carried out in F1, F2. When crossing plants of different races, Col-0 and La-0, hybrids of the first generation showed somatic heterosis, which manifested itself in a more powerful development of the rosette of leaves compared to the original forms. In the second generation there was a process of splitting hybrids, and their superiority in diameter of the rosette of leaves over the parental forms was reduced. This is due to a decrease in the heterozygosity of plants in the F2 generation. In the cross examined, a stronger development of the diameter of the rosette of leaves is associated with the action of two pairs of polymer genes. To repeat the heterosis in self-pollinating plants in subsequent generations, without resorting to complex seed production and a system of recurrent, stepwise crossings, it is possible with the help of an analyzing crossing when crossing a dominant homozygote with a recessive homozygous of F 2 hybrids (AABB × aab → AB). Through the fact that the maternal form was the dominant homozygote, the phenotype does not split. In this case, in self-pollinating plants, it is possible to fix heterosis in subsequent generations when selecting such genotypes in F 2 with an extreme degree of expression of sign. In order to identify these genotypes in F 2 plants, it is possible, using the halves method, to conduct analyzing crosses with a recessive homozygote on the basis of heterosis. The use of analyzing crosses and the halves method with single individual selection in self-pollinating plants makes it possible to speed up the selection process by shortening the time for multiple inspection by progeny of selected individual plants, related to the phenomenon of splitting in generations of selected elite forms. In the case of a polymer in self-pollinators in the second generation, a transgression phenomenon is often observed. Transgressive variability, which usually appears in hybrids of the second generation, can be considered one of the forms of heterosis in self-pollinating plants. In this case, F2 plants have stable genotypes (dominant or recessive homozygotes), combining polymeric genes of additive action, causing the extreme manifestation of an economically valuable trait, in the selection of which in the future, it is possible to obtain a new variety whose yield exceeds the parent pairs by 20 -40%. Key words: Arabidopsis thaliana (L.) Heynh, heterosis, gene, mutation, race