Assessing the effect of selected PGRs on yield, fruit quality and morphology of 'Fireprince' peaches

Winter seasons with erratic and uncommonly high temperatures can lead to insufficient chilling accumulation in fruit crops in the Southeastern US that can result in lack of crop or plant dieback in peach trees. Furthermore, high temperatures during fruit development can increase the occurrence of protruding tips and formation of pronounced sutures in peach cultivars. An experiment was established in 2015-2016 at the Chilton Research and Extension Center near Clanton, Alabama to assess the effect of various PGRs and treatment rates as a means to overcome insufficient chilling accumulation and mitigate its negative effect on total yield, fruit quality and fruit morphology of 'Fireprince' peaches. Experimental design was RCBD with 5 single tree replications. Eight PGR treatments were applied to mature 'Fireprince' peach trees during December 2015 - February 2016 when chilling hour accumulation was about one third below the area historic average, and less than 69% of the reported chilling requirement of 'Fireprince'. Total yield and fruit quality data were collected. To determine fruit morphology, fruit shape was measured and shape, suture deformation, and shape indices were calculated. Visual fruit shape ratings were recorded and fruit shape was also image-analyzed using Tomato Analyzer 3.0 software. The results suggest no consistent treatment effect on 'Fireprince' total yield, number of fruit per tree, fruit size, or fruit shape and morphology. Future research is needed to evaluate the effect of PGRs on cultivars with higher chilling requirements or in years/environments with more severe chilling hour insufficiency.