Conversion rate and yield of arabica coffee genotypes evaluated in a competition trial in Ervália - MG

Information on the conversion rate (CR) of coffee cherries to green coffee in Coffea arabica is essential for selecting cultivars that require a smaller volume of harvested cherries to produce a 60-kg bag of green coffee. This study aimed to evaluate the CR and yield of cultivars and advanced progenies from the Arabica Coffee Breeding Program. The experiment was conducted in 2021 in Ervália, Minas Gerais, Brazil (20º54'19.42''S, 42º37'37.36''W; 840 m altitude). Thirty-eight cultivars and progenies were evaluated in 2025 using a randomized complete block design with four replicates and plots of 10 plants, spaced 2.80 × 0.70 m apart. To determine the CR (L·bag⁻¹), 3 L of cherries were collected per plot, sun-dried on raised beds to 11.5% moisture, and weighed. The dried samples were then hulled, and the resulting green beans were weighed. The CR was calculated as the ratio between the dry coffee weight (from the 3 L sample) multiplied by 60 kg and the green coffee weight, with all weights corrected to 11.5% humidity. The volume of cherries harvested per plot was extrapolated to yield (bags·ha⁻¹). Analyses of variance (ANOVA) were performed for all traits. When significant differences were detected by the F-test, means were grouped using the Scott–Knott method at the 5% probability level. All analyses were conducted in the software R. Significant differences were observed among genotypes for CR (p = 1.74 × 10⁻⁵), whereas yield differences were not significant (p = 0.15). The lack of yield variation among genotypes was likely due to adverse environmental conditions, including a pronounced water deficit in 2025 and the high sand content of the soil (54%), which limited water and nutrient availability. The Scott–Knott method identified two groups for CR. Group 1, comprising 23 genotypes, had a mean CR of 745.06 L·bag⁻¹, representing cultivars with lower conversion efficiency. Group 2, with 15 genotypes, had a mean CR of 593.21 L·bag⁻¹, representing cultivars with higher efficiency. These results demonstrate significant genetic variability in CR among C. arabica genotypes, enabling the identification of more efficient cultivars for converting harvested cherries into green coffee. The absence of yield differences was attributed to the unfavorable soil and climatic conditions during the crop cycle.