Effects of testing conditions of complex interspecies potato hybrids, their backrosses on the average weight of commercial tubers

Abstract

Purpose and objectives. To determine the potential of complex interspecies potato hybrids, their backcrosses in terms of the average weight of commercial tubers and to identify the effects of exrenal conditions on the trait expression.Materials and methods. The study was conducted in two soil-climatic zones: the northeastern forest-steppe of Ukraine (Sumy National Agrarian University) and southern woodlands of Ukraine (Institute of Potato Growing) in 2015–2017. We studied the influence of external conditions on the average weight of commercial tubers in 34 complex interspecies hybrids and their backcrosses. The technique was common in experiments on potato.Result and discussion. A high potential of the material under investigation was recorded for the average weight of commercial tubers with the maximum expression of the indicator in a double backcross of four-species hybrid 00.72 /5 in SNAU in 2017 –217 g.We experimentally proved the influence of the external conditions: the study locations and meteorological conditions during the growing period on the trait expression. Hybrids with the average weight of commercial tubers of >100 gin the SNAU conditions were the most frequent in 2017 (23.5%) and the least frequent in 2015 and 2016 (4.9% and 3.9%, respectively). In the IPG, there were no such hybrids in 2015 or 2017; their percentage only was 1.0% in 2016.The high potential of the material under investigation in terms of the trait expression is confirmed by occurrence of hybrids with an increased level of the indicator than that in the best standard variety, which was observed regardless of the external conditions.The best conditions for the formation of commercial tubers with the maximum weight were in SNAU in 2017; their percentage was 27.5% of their total number. Close, albeit lower, percentages were achieved in the IPG in 2016 and 2017: 15.7 and 13.7%, respectively.We observed significant effects impact of the external conditions during the potato growing period on the indicator expression. In SNAU trials, most of the hybrids had the variation coefficients within 21-30% and 31-40%, and in the IPG conditions they were £ 10% or 11-20%. The above-said was also confirmed by categorization of the hybrids, depending on the experiment location and the conditions during the growing period. In SNAU, 2017 was the most favorable for the trait expression. The opposite was true for2015. Inthe IPG, the best distribution of the material by the high average weight of one commercial tuber was noted in 2016 and the worst - in 2015.We revealed different relationships between the genetic control of the trait and the external conditions in sibling forms, which was manifested as various expression of the indicator depending on the trial location and the meteorological conditions in the trial years.Conclusions. The influence of the conditions in the study location and the meteorological conditions during the growing period on the expression of the average weight of commercial tubers was demonstrated. They affected the fulfillment of the genetic potential of the accessions under investigation, its maximum manifestation, the variation coefficients, and categorization of the hybrids into classes of the indicator values.