Maturation cycle and fruit-to-bean conversion ratios in amazon robusta coffee cultivars

– This study aimed to characterize the outturn index, field outturn index, uniformity of maturity, and maturation cycle of fifteen Coffea canephora genotypes grown in different environments of the Western Amazon. Conducted in Amazonas (Itacoatiara and Manaus) and Rondônia (Porto Velho), the research evaluated the performance of ten cultivars and five promising genotypes from Embrapa. The genotype × environment interaction was significant, indicating different performance of clones across environments. Genotypic coefficients surpassed environmental ones, indicating a genetic influence on outturn indices and uniformity of maturity. The mean outturn index was 24.68%, and the field outturn index was 22.57%, with Itacoatiara having the highest mean values. The overall mean fruit uniformity of maturity was 63.02%, with Porto Velho achieving the highest mean uniformity value (71.78%). The cultivar BRS1216 exhibited the best performance for outturn indices and provided the highest gain from selection across environments, showing wide adaptability for the outturn index and adaptability to environments favorable for field outturn. Cultivars BRS3210 and BRS3220 achieved more than 82% uniformity of maturity across locations, with BRS3210 adapting to favorable environments and BRS3220 adapting to unfavorable ones. Additionally, BRS3220 had a high mean field outturn index, indicating wide adaptability and high phenotypic stability. The evaluated Amazon Robusta clones and cultivars displayed the expected maturation cycles.