Peach cell number and size is affected by crop load and cultivar
Peach fruit development is impacted by crop load, cultivar genetics, and temperature during the Phase I growth stage after fruit set. Four peach cultivars, 'Carored', 'Summerprince', 'Scarletprince' and 'Redhaven', ripening from mid-May to early July were selected for fruitlet sampling every 5 days from week 2 to week 5 post-bloom. Fruitlets were collected mid-shoot, 1.5 m above ground, from the exterior of all four sides of the tree. Fruitlets were fixed with FAA (ethanol-formaldehyde-acetic acid) before mounting for sectioning. Trees of each cultivar were either thinned one week or four weeks after petal fall. There were four single-tree replicates for each cultivar and treatment. Mesocarp cell number and size were recorded from transverse sections using Infinity Analyze software. Differences in cell number due to crop load were observed within days after early thinning. Early thinned trees had 8 to 19% more cells than later thinned trees 3 weeks after the first thinning date. At week 4 post-bloom, the two later ripening cultivars, 'Redhaven' and 'Scarletprince', had more cells than the two early ripening cultivars. Differences in cell size occurred with 5 days of thinning for the earliest cultivar, 'Carored'. The other 3 cultivars did not see differences in cell size between treatments until 2 weeks after the earliest thinning treatment. Three weeks after the early thinning, fruit from early thinned trees had cells 5% ('Summerprince') to 43% ('Carored') larger than the later thinned trees. At week 5, early cultivars had larger cell size than the later ripening cultivars. Fruit from the early thinned trees ripened earlier and were larger at harvest.
Reighard, G.L., Souza, F.B.M. and Pio, R. (2017). Peach cell number and size is affected by crop load and cultivar. Acta Hortic. 1160, 357-360
Prunus persica, thinning, cell division, mesocarp, fruit size, growing degree days