# Effect of Growth Regulators on the Quality of Apple Tree Whorls
## 3 Results  
The study presents weather conditions, determining the average air temperature and total precipitation in the 2017-2019 growing season against the background of multi-year averages. It was found that the average air temperature in the study years was higher than the multi-year average. In 2018 and 2019, the average air temperature for the growing season was 2.5 \({}^{\circ}\)C higher than the multi-year average. A similar trend was shown for the analyzed weather parameter in all months of the growing season (Figure 1). The sum of precipitation in the analyzed study period was distributed differently depending on the growing season. In 2017, the sum of precipitation for the growing season was 292.0 mm higher than the multi-year average, in 2018 it was 61.0 m higher, while in 2019, it was equal to the multi-year average. The month with the highest precipitation in 2017 was June (282.0 mm), in 2018 July (124.0 mm) and in 2019 August (102.0 mm). The months with the least amount of precipitation were May (29.1 mm) in 2017, 2018 (36.0 mm) and 2019 (29.0 mm) October (Figure 2). Figure 1: Average monthly air temperatures according to the agrometeorological station in Strzeszkow-ice, municipality of Niedzwica Duza in the months of April-October in the years 2017-2019 (Hortic PROCAM). Significant difference a, b, c, d mean that different letters between columns indicate significant differences between survey years in each year at \(\alpha\) = 0.05. The height of the perianths of two apple cultivars 'Alwa' and 'Najdared' was assessed at four dates, i.e., the first height measurement was carried out on the day of the first application of growth regulators; the second height measurement was carried out 10 days later and at the same time during the second application of growth regulators; the third height measurement was carried out 10 days after the second measurement and in autumn after the end of growth. Significant influence of the type of growth regulators applied and the variety on the studied trait was shown. The perianths of the 'Alwa' cultivar treated with BA + GA\({}_{3}\) were significantly (\(p<0.0001\)) the highest in the first three height measurement dates, and during the autumn measurement, those treated with BA + GA\({}_{4+7}\). During the first and second height measurements, the perianths of the cultivar under study treated with BA + GA\({}_{4+7}\) were significantly (\(p<0.0001\)) the lowest, while during the third and autumn measurements, the control perianths were the lowest. In the cultivar 'Najdared', during the first measurement in the control combination and in the subsequent measurement dates, the BA + GA\({}_{3}\) treated perianths were significantly (\(p<0.0001\)) the highest of the tested combinations. In the case of this cultivar, the BA + GA\({}_{4+7}\)-treated rootstocks in the first two measurement dates and the control ones during the third and autumn measurement dates were significantly (\(p<0.0001\)) the lowest among the evaluated combinations (Table 1). Another analysis was performed to check for significant differences between the tested varieties within each combination. In the case of control trees, regardless of the measurement date, the trees of the 'Najdared' variety were significantly taller than the Alwa trees (\(p<0.0001\)). Trees of the 'Najdared' variety treated with growth regulators, regardless of the type of preparation, were significantly (\(p<0.0001\)) taller than those of the 'Alwa' variety in the first three dates of height measurement; in autumn, this trend was reversed (Table 1). A significant effect of cultivar on the final height of apple trees was found in studies by [PERSON] (2006) [PERSON] (2006) [PERSON] (2006) regardless of the type of nursery stock. In these studies, both perianths and biennial trees of the cultivar 'Jonica' were taller than those of 'Shampion'. [PERSON] et al.