The Applications of Different Glycine Betaine Doses on Young Pear Trees Under Drought Stress Conditions.

This experiment was conducted at the Fruit Research Institute, MAREM, Eğirdir-Isparta, Turkey, to detect the effects of different glycine betaine doses in drought stress conditions on young pear trees in 2019. The pear trees used in the study were one-year-old Deveci (Pyrus Comminus L.) variety grafted onto OHxF 333 rootstock. There were three different irrigation treatments in the experiment. Treatments were I₁₀₀ treatment—available soil water reached field capacity for each irrigation, 100% (control); I₅₀ treatment—irrigated with 50% of the water used in the I₁₀₀ treatment (50% water deficit, moderate stress); I₂₅ treatment—irrigated with 25% of the water used in the I₁₀₀ treatment (75% water deficit, severe stress). Four different GB doses were used: GB₀: 0, control; GB₁: 1 mg L⁻¹; GB₅: 5 mg L⁻¹; and GB₁₀: 10 mg L⁻¹. GB was not applied to pear trees in the I₁₀₀ treatment. That is, there were nine different treatments in this study. GB applications provided a 19% increase in Pn of both the I₂₅ and I₅₀ treatments. According to the results of g_sw, g_sw increased between 18.0% and 27.8% for GB₅₀ and GB₂₅ treatments, respectively. In total, 10.9% and 14.8% increasing rates in shoot length were detected in GB₁₀ applications in both the 50% and 75% water deficit treatments. The highest trunk diameter and fresh root weight results were determined in 10 mg L⁻¹ GB dose applications under 50% water deficit conditions (I₅₀GB₁₀). [ABSTRACT FROM AUTHOR]