FORMATION OF POTENTIAL PRODUCTIVITY OF DIFFERENT PEACH CULTIVARS IN THE CONDITIONS OF THE SOUTHERN STEPPE OF UKRAINE

Abstract

The article is devoted to a comprehensive study of the main aspects of peach yield formation depending on the influence of cultivar characteristics and weather conditions of the research years in order to adjust main yield-regulating pruning of orchards. Unlike other temperate fruit crops, peach cultivation technology includes strong annual pruning of the trees to maintain sufficient tree vigour and regulate the crop load. The aim of the research was to determine the influence of cultivar peculiarities and weather conditions on the total formation of flower buds on one tree with subsequent adjustment of cultivar- specific pruning to obtain stable yields of high quality peach fruits.The research was carried out in a field experiment during 2017-2019 in the Southern Steppe of Ukraine in the orchard of 7-9 years of age on 6 peach cultivars. Observations included analysis of weather conditions of the zone, determination of the structure of annual tree shoot growth depending on cultivar genotypes and conditions of the year, density of generative buds on different types of shoots, total number of flower buds on trees before dormancy, statistical analysis of experimental data. ‘Posol myru’ cultivar was the most vigorous in the conditions of the study (total annual shoot growth of trees at the level of 151.2 m), while ‘Yuvileinyi Sydorenka’ and ‘Vireneia’ cultivars were the least vigorous (96.2 and 98.3 m, respectively). In the structure of total shoot growth, the share of mixed annual proleptic shoots amounted to 53-80%, of summer sylleptic shoots – 5-16%, and of spurs – 3-23%. ‘Redhaven’ and ‘Krymskyi feierverk’ cultivars had the highest flower bud density on mixed annual shoots, where the bulk of the peach yield is concentrated – 51.0 and 51.3 buds per 1 running m of the shoot on average for three years of the research, respectively. It should be noted that this index significantly depended on both cultivar characteristics and weather conditions during the generative bud differentiation. ‘Posol myru’ cultivar was selected as the one with the highest productivity potential – an average of 6210 generative buds on a tree, which was 1.1-2.2 times higher than other cultivars.As a result of the research it was determined that in order to obtain the planned yield of 15-20 t/ha while maintaining high quality of the fruits, up to 70% of annual shoot growth should be removed during pruning of peach trees of ‘Posol myru’ cultivar, 60-65% – for ‘Krymskyi feierverk’, ‘Skazka’ and ‘Redhaven’ cultivars, and only 30-40% – for ‘Yuvileinyi Sydorenka’ and ‘Vireneia’ cultivars.