Evaluating genetic and environmental effects upon sweet cherry cultivars differing in seasonal duration and fruit size, Gibeau et al. employ photographic measurements to apply a framework of biological time indices demarcated by the degrees of growth of reproductive buds, ovarian volume and pits from dormancy to maturation.
The initial growth phase is defined by the acceleration of ovary growth in the (minimum) two weeks preceding anthesis, coinciding with bud scale separation. Post-anthesis, unfertilised or otherwise unsuccessful individuals were eliminated statistically with discriminant function analysis prior to polynomial curve fitting and estimation of developmental time. Developmental differences across early, mid and late-maturing cultivars were not detected until the final growth period.
Gibeaut, D. M., Whiting, M. D., & Einhorn, T. (2017). Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth. Annals of Botany, 119(3), 465–475. https://doi.org/10.1093/aob/mcw232