Ripening cycle and its relationship with fruiting in advanced Coffea arabica L. progenies derived from intra- and interspecific crosses

Introduction: The fruit ripening cycle is a key factor in coffee production because it directly influences harvest scheduling and crop environmental adaptability. Therefore, evaluating the variability of this trait in different progenies and its association with the source-sink relationship and fruit characteristics is fundamental for optimizing production and breeding. Methods: In coffee progenies derived from intraspecific and interspecific hybridization, the ripening cycle was recorded using growing degree days (GDD) during the main and secondary harvest periods. Concurrently, variables related to climate, source-sink relationships, fruit characteristics, and fruit load dynamics were recorded. Multivariate clustering and variable selection methods, semiparametric multivariate analysis with repeated measures, and non-parametric longitudinal data analysis were implemented for data interpretation. Results: The progenies were classified into three clusters. The early- and late-ripening clusters presented the lowest and highest GDD values, respectively, across harvests. In contrast, stable-ripening progenies presented low GDD variation across harvests. The effect of ripening directly impacts the dynamics of the fruit load harvested over time. Variations in the source-sink relationship variables and physical fruit characteristics were attributed primarily to the fruit load. The hybridization origin was not associated with the variability of the ripening cycles. Discussion: The consistent performance of early- and late-ripening progenies at each harvest, despite variable ripening cycle durations, and the low sensitivity to inter-harvest changes in stable progenies indicate that the progenies respond differently to environmental conditions. This response directly influences the fruit load dynamics. The ripening cycle duration may be indirectly influenced by the source-sink relationship, but not by physical fruit characteristics or hybridization. The latter, due to the sample size, should be interpreted with caution and verified in future studies.