Monoculture of modern cereal crops are popular due to the technical and organizationa lreasons. They are easier in crop husbandry, qua lity and product use. However, in monoculture chemical protection of crops is a norm, due to the fact that they are more susceptible to diseases, pests and sometimes weed infestation. In order to keep high and stable grain yields and quality in monoculture one has to use high inputs. Experimentally and practically it has been proved that cultivar and species mixtures can constitute an alternative to cultivar growing in pure stands. It has been found that in mixtures opperate different epidemiological and ecological factors, which lead to considerable disease reduction, pest and weed control, which finally result in higher and more stable grain yields than in barley varietes grown in pure stands. The results of two years field experiment designed to evaluate epidemiological and economical effects of winter barley cultivar mixtures are presented. The studies were carried out in two sites – experimental lStation for Variety Testing Słupia Wielka (in Wielkopolska region) and Plant Breeding Station Bąków (Opole District). This two sites were 300 km away from each other, and had different soi land meteorological conditions. In the experiment impact of different barley cultivars and their different two- and three-component mixtures were tested with reduced dosages of fungicidies on grain yield in the mixtures compared with pure stands were evaluated.
Gene postulation is one of the fastest and most cost-effective methods for identifying seedling leaf rust resistance genes in wheat cultivars. Many researchers use this approach to identify Lr genes in wheat cultivars. The purpose of our research was to identify seedling leaf rust resistance genes in 20 wheat cultivars from different breeding centers of Russia, Ukraine and Germany. Forty-two near isogenic Thatcher lines and 10 Puccinia triticina isolates were used for gene postulation. When assessing the infection types to cultivars and lines, a scale was used, according to Oelke and Kolmer. In 20 wheat cultivars 19 Lr genes were postulated: 2c, 3, 10, 3bg, 3ka, 14a, 17, 18, 23, 25, 26, 30, 33, 40, 44, 50, B, Exch, Kanred. The most common for cultivars was the Lr10 gene. In five cultivars, showing high field resistance, most postulated seedling genes (Lr2c, Lr3, Lr10, Lr14а, Lr26, Lr33) were not effective in the adult stage. It is possible that resistance of such cultivars is associated with APR genes, the postulation of which requires an expansion in the number and spectrum of P. triticina isolate virulence. Most of the studied cultivars (60%) have recently been entered into the register (2015–2019) and in the field show a stable or moderately susceptible response to P. triticina infection, despite the fact that the Lr genes postulated in them were not effective in the adult stage. The data obtained indicated a variety of genotypes of the studied cultivars, as well as the tendency of breeders to use the effect of pyramiding ineffective genes, which can prolong the resistance of the cultivar. Annual monitoring of varieties is necessary in each region, especially when reacting with a medium susceptible type (MS), which may indicate the initial stage of resistance loss.
Clarifying the genetic background of the drought-tolerance trait is a crucial task that may help to improve plant performance under stress by a genetic engineering approach. Dehydration-responsive element-binding protein (DREB) is a transcription factor family which modulates many stress-responsive genes. In this study, we isolated a DREB homolog gene named ZmDREBtv from Zea mays var. Tevang-1. Using bioinformatic tools, a number of InDels and SNPs in ZmDREBtv sequence different from the reference accession were identified. In addition, based on deduced protein sequence similarity, ZmDREBtv was assigned to transcription factor DREB2 class as featured by a conserved DNA binding domain - AP2. The ZmDREBtv construct under thecontrol of the rd29A promoter was transformed into a drought-sensitive maize plant, K7 line. The transgenic plants were assessed with reference to molecular and phenotypic characteristics related to the drought-tolenrance trait. The results proved that the maize plants carrying ZmDREBtv gene showed enhanced tolerance and better performance to the water-deficit environment at different stages, compared to the wild-type plants.