Exposure of spring frosts on reproductive parts of apple trees (Oryol Oblast, Russia)

During apple flowering, unfavorable weather conditions such as spring frosts can adversely affect the yield and quality of the fruit formed, although the degree of impact differs depending on the apple variety. This article presents the results of field observations on the effect of spring frosts in May 2023 and May 2024 on reproductive formations of different apple varieties and the manifestation of their effects on yield. The extent of damage to flowers and buds by low spring temperatures in different apple varieties was analyzed. In 2023, the intensively flowering variety Belorusskoye Sladkoye (5 points) was found to have an actual damage of 78.3 % to flowers and 42.3 % to buds when an air temperature reduced to -4.2 °C. However, the fruit yield amounted to 28.7 kg/tree (11 t/ha), implying that spring frosts did not have a negative impact on yield. Moreover, high yields of late-flowering apple varieties Zdorovie , Serafima , and Veniaminovskoe were observed. In 2024, the least damage to flowers and buds at a decrease in air temperature during flowering to -6 °C was detected in the Ligol , Honey Crisp , and Rozhdestvenskoye varieties. High yields were measured in such varieties as Honey Crisp (USA), with 13.9 kg/tree (7.8 t/ha), Ligol (Poland), with 13.5 kg/tree (4.8 t/ha), Serafima (Belarus), with 12.3 kg/tree (7.7 t/ha), Veniaminovskoe (Russia, Russian Research Institute of Fruit Crop Breeding), with 11.1 kg/tree (9.6 t/ha), and Belorusskoye Sladkoye (Belarus), with 10.6 kg/tree (11 t/ha). Thus, in 2023, spring frosts during the flowering period produced no negative effect on the yield of the Belorusskoye Sladkoye , Zdorovie , Rozhdestvenskoye , Serafima , and Veniaminovskoe varieties. In 2024, spring frosts that lasted from May 3 to 14 (-2.0 °C) equally had no impact on the yield reduction of late-flowering apple varieties Honey Crisp , Ligol , Serafima , Veniaminovskoye , and Belorusskoye Sladkoye .