The number of tubers in the bush in interspecific of the potatoes, their beckcrosses depending on the conditions of growth

The experiments proved the value of many complex interspecific hybrids, their backcrosses according to the ability to tie more tubers in the nest than the best standard variety. Under the favorable external conditions, it was measured at more than 20 pieces/nest. In most hybrids, a significant impact on the implementation of the indicator of the places for the research (Sumy National Agrarian University and Ustymiv Research Station) and meteorological conditions of the years of the experiment (2015-2017). Based on the data on the distribution of hybrids by the quantity of the tubers in the nest, it has been found out that the best conditions for the manifestation of the signs were in SNAU in 2015 and 2016, and in the Ustymov research station in 2015. The biggest number of hybrids (6 pcs.) with the difference of 7 tubers/nest depending on the places of the experiment were found out in 2017 and the lowest number – in 2015. The opposite was true for the minimum difference in the manifestation of the indicator - 1 tuber/nest and less. Only single hybrids were characterized by a low value of the coefficient of variation of the manifestation of the sign (3-9%). The nursing forms reacted differently to the external conditions by the ability to tie tubers. Key words: tubers, interspecific hybrids, their backcrosses, number of tubers in the nest, meteorological conditions, places of the experiments, coefficient of the variation.