Manifestation of the average mass of commercial tubers in interspecific hybrids of potatoes, their backсroses depending on the place and years of the test

The successes in the selection of potato in the direction of creating varieties with a large average weight of commercial tubers depends on the quality of the source material, very desirable with the combination of high manifestation of the sign and the stability of its expression, regardless of external conditions. The researches were carried out in 2015–2017 under the conditions of the Ustymovskaya Research Station Plant (URSP) and the Sumy National Agrarian University (SNAU) in accordance with generally accepted methods in potato-growing. The starting material used different methods of creation, origin, degree of backing complex intraspecific hybrids with the participation of Mexican wild species. Significant potential of individual backcrosses has been revealed at the sign of a sign that is up to 1.8 times more than in the best grades. At the same time, he realized, depending on the external conditions is far from complete. Only in the most favorable for the meteorological complex in 2017, under the conditions of the SNAU, the proportion of hybrids having an average mass of one commercial tubers of more than 100 g was 75.8 %, and in the URSP it was 2,3 times less. The favorable conditions of the growing season of potato in 2017 are also evidenced by the proportion of hybrids with the maximum manifestation of the trait. In SNAU it was 28.3 %, and URSP – 25.3 %. The variability of the expression of the indicator at the test site is evidenced by the magnitude of its coefficient of variation. In the conditions of SNAU and URSP, the proportion of hybrids with a coefficient of variation of 10 % or less was 9.1 %. At the same time, in some hybrids the value of the indicator turned out to be very high – 50–70 %. Allocated hybrids, in which in each year the difference in the manifestation of the trait does not exceed 10–11 g, depending on the test site, namely: 90.673/30, 08.194/23 and 08.194/25, and in the hybrid 08.194/122 it was observed during 2015 and 2016 years. A different reaction of sister forms to the influence of the external complex was revealed. Among the hybrids 88.1450s2 and 88.1450s3 only in the latter under the conditions of the SNAU meteorological conditions almost did not affect the manifestation of signs – the coefficient of variation was 8%. With a difference of 1 g, the average mass of commercial tubers in this hybrid in the SNAU and URSP in 2015 was revealed. As a result of the study, it was possible to identify hybrids with a stable expression of the indicator irrespective of the meteorological conditions (08.194/25), for trials for three years in the SNAU (88.1450s3), URSP (08.194/33,08.194/119) and experimental locations (90.673/30,08.194/23 and 08.194/25). They are recommended for use in the breeding process with high adaptability.