The present research paper aims at comparing the similarity and remoteness of influence of the features of eight common wheat varieties and their grouping on the base of important structural indicators through the use of a mathematical approach and a cluster analysis; studying of a relationships between the examined indicators in order to make more objective evaluation using the possibilities of the factor analysis; reducing the number of correlating indicators into new factors. Two-year data were used, obtained from the examination of eight common wheat varieties. The subject of the present research were seven seven foreign varieties of wheat - Ingenio, Bologna, Dalara, Moyson, Falado, Gabrio, Pibrak, and the eighth variety - Factor - was a local Bulgarian selection. The introduction of common wheat varieties is related to the study of their productivity and ecological plasticity. For this purpose there were reported and analised yield structural elements: plant height, wheat-ear length, number of ears, number of grains per ear, weight of grains per ear, grain yield from hectare. The cluster analysis showed that the influence of wheat variety on the qualitative indicators led to their grouping into two new clusters. There was established a strong positive correlation between the number of grains per ear and the hectoliter mass (r = 0.811) as well as between the number of ears and the weight of grains per ear (r = 0.771). The correlation coefficient between the number and weight of grains - (r = 0.649). The factor analysis established the influence of three main factors influencing the group formation of wheat varieties. The first factor was related basically to plant height, ear length, number of grains per ear and hectoliter mass. The second component was basically related to the number of ears and weight of grains. The third factor was related to the mass of 1000 grains.

in Romania, climate change has determined in recent years, the intensification of water deficits (often associated with scorching heat) during the vegetation of agricultural crops, in almost all areas of the country. The cultivation of winter wheat varieties that can withstand drought and heat well and the adaptation of cultivation technology to climate change are decisive factors in obtaining stable and economically efficient yields. In the agricultural years 2018/2019 - 2019/2020, at ARDS Teleorman, a multifactorial experiment of type 3 x 3 x 2 was set up, which aimed to determine an optimal density depending on the varieties used and climatic conditions. The experiment was placed according to the method of plots subdivided into 3 repetitions, with the following factors: Factor A variety, with 3 graduations (a1 = Glosa; a2 = Avenue; a3 = Rubisko); Factor B density, with 3 graduations (b1 = 400 g.g./m2; b2 = 650 g.g./m2; b3 = 750 g.g./m2); Factor C year, with 2 graduations (c1 = 2018-2019; c2 = 2019-2020). The highest yield was obtained by the variety Rubisko (9,282 kg/ha), compared to the average of the tested varieties. On average, the highest yields were obtained at a density of 650 g.g./m2 (9,266 kg/ha).