Impact of repeated yearly applications of prohexadione-calcium on vegetative and reproductive growth of ‘Golden delicious’/M.9 apple trees

Growth retardants have great potential to balance between vegetative and reproductive growth. To assess the effects of prohexadione-calcium (Pro-Ca, Regalis) on reproductive and vegetative growth, return bloom, fruit set, and also fruit quality in ‘Golden Delicious’ apple grafted on M.9 rootstock, an experiment was performed during 2010-2012. The applications of 125 mg dm-3 Pro-Ca on the same trees in each year resulted in a 40-43% shoot length reducing. Internodes length decreased with Pro-Ca at about 30%, while total node number was unaffected. Results indicate that Pro-Ca applications have no effects on tree trunk growth, flowering, yield, fruit set and development. Pro-Ca also didn’t have any negative impact on fruit quality during the three consecutive years. Moreover, Pro-Ca resulted in higher fruit size compared to control in the third year of trial. The results of this experiment clearly suggest that fruit growers can use Pro- Ca for the control of vegetative growth without having any negative effects on fruit quality and yield parameters. Once a full canopy has been achieved, annual shoot growth can be suppressed in the range of 20 to 30 cm with 125 mg dm-3 Pro-Ca treatment in ‘Golden Delicious’ apple trees

Orchard performance of apple worsens as weed competition increases: a long-term field study under Mediterranean conditions

Crop-weed competition (CWC) for water and nutrients can negatively affect orchard performance, especially in high-density apple orchards. With this study, we compared the effects of three CWC levels: Weak, Moderate, and Strong for the orchard performance of apple in the Mediterranean area. The study was conducted at a ‘Golden Delicious’/M.9 orchard in a high-density formation (3.5 × 1 m spacing). Cumulative yield was greatest in Weak-CWC, and it decreased as CWC increased. Overall, Weak-CWC performed remarkable results for successful apple production under Mediterranean conditions