2018 ASHS Annual Conference

During the early growing season, fruit growth is limited by competition among fruits for available resources. Thinning is a cultural practice commonly performed in tree fruits to reduce this competition and maximize fruit growth. Reducing crop load can lead to a larger fruit size and ultimately a higher total yield. The timing of thinning in relation to fruit development, and its intensity impact the efficacy of the treatment. Furthermore, the response to thinning can be cultivar dependent and can be affected by local weather, especially during early spring. The objective of the current study was to evaluate various timings and intensities of thinning for several cultivars grown in Georgia. We evaluated the effects of three thinning times (at bloom, ~40 days after bloom, ~60 days after bloom) and two intensities (fruit spaced either at around 15 cm or at 20 cm on the shoot) in three peach cultivars, CaryMac, Springprince, and Juneprince in 2017. No significant differences were observed among thinning treatments for final yield, fruit weight, diameter, titratable acidity, or soluble solids content. Substantial lack of chill hour accumulation as well as a late spring freeze in 2017 likely had a major effect on thinning responses in these cultivars. Under such winter and early spring weather conditions, thinning is not likely to benefit the resulting crop.