Estimating Heat Requirement for Flowering in Peach Germplasm

Bloom date (BD) in peach is determined by the dynamic relationship between chilling (CR) and heat requirement (HR) fulfilment during dormancy. Understanding these thermal requirements would enable breeders to adapt new cultivars variable climates. Among three traits, HR least investigated, with genetic variability germplasm interaction HR, CR BD still mostly unknown. Therefore, we investigated of 136 over 8 growing seasons (2014–2021) calculating degree hours (GDH) from moment their was satisfied until full bloom. The ranged 1362 10,348 GDH across years cultivars, cultivar eight-year having best linear unbiased prediction (BLUP) values 4808 7721 GDH. In addition, a high positive correlation CR, negative seasonal effect on were observed. Moreover, simulating different threshold base temperatures (Tb) revealed trends accumulation, suggesting that genotype-specific Tb should be allow precise discrimination this requirement. Peach showed variation could used breeding for bloom delay environments climate change.