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Thirteen lines from the coffee germplasm collection of the Adjuntas Agricultural Experiment Substation, lines T-5175 and T-8667 from Costa Rica, and four advanced multilines from the Portugal Research Center for Coffee Rust (CIFC; ‘Centro de Investigación de la Roya del Café de Portugal’) were evaluated for resistance to Hemileia vastatrix and their performance under coffee production conditions in Puerto Rico. The evaluations were conducted in the laboratory and on selected coffee farms. Lines of “Catimor” and “Sarchimor” types were selected based on their reaction to the rust pathogen and excellent agronomic characteristics and named ‘Frontón’ and ‘Limaní’, respectively. Incidence of black beans was examined in red, medium and green beans and was significantly higher in line T-5175, in plantings

Studies were conducted in the central mountainous region of Puerto Rico to determine the adaptability of 18 pummelo clones. Data on fruit number, weight and yield efficiency were collected during three consecutive crop years beginning the fourth year after planting. Clones Dry Pink, Thong Dee White and African Seedling were the best in terms of total number of fruits produced per tree, Production increased with age from over forty fruits for four-year-old trees to over sixty fruits per tree for six-year-old trees. Fruit weight per tree also increased with age, reaching a maximum of 87 kg of fruit for six-year-old trees. Clones Dry Pink and Thong Dee White were the best in terms of total fruit weight. Yield efficiency measured in terms of number of fruits per cm of stem diameter also increased with age from an average of 5.50 for four-year-old trees to 7.55 for six-year-old trees. Best yield efficiency was obtained with clones Dry Pink, Reinking, Thong Dee White and Green Favorite. These results indicate an excellent adaptability of the pummelo to the soil and climate conditions prevailing in the central mountainous region of Puerto Rico.

Se realizaron aplicaciones de ácido giberélico (GA), paclobutrazol y ácido giberélico (Paclo/GA), fluoridone y ácido giberélico (FL/GA), y ácido abscísico (ABA) con el propósito de sincronizar la floración del cafeto (Coffea arabica L.). Ninguno de los tratamientos afectó el crecimiento del árbol ni de las ramas. Los tratamientos no afectaron significativamente la producción de hojas nuevas; sin embargo, se observó una tendencia en el tratamiento con Paclo/GA a incrementar el número de ramas secundarias. La producción de yemas florales se afectó con el tratamiento de ABA durante las primeras tres semanas, mostrando una reducción inicial en el número de yemas y un comportamiento tardío en su desarrollo. El tratamiento de GA resultó en una mayor cantidad de flores durante la primera semana de evaluación y un mayor número y peso de frutas maduras durante el primer mes de cosecha.

Se detectaron cancros en el tallo y pudrición de la raíz pivotal de cafetos en el vivero. Estas lesiones inducen proliferación de raíces adventicias en la porción inferior del tallo. Se aislaron varios hongos de las lesiones de los tallos y de las raíces y se realizaron pruebas de patogenicidad bajo condiciones húmedas de umbráculo. Los síntomas típicos de la enfermedad se reprodujeron en el tallo y en la raíz de las plantas inoculadas con Myrothecium roridum y Rhizoctonia solani.

SUSCEPTIBILIDAD DE 53 CULTIVARES DE CAFÉ, COFFEA ARÁBICA, AL DAÑO DEL MINADOR DEL CAFÉ, LEUCOPTERA COFFEELLA, EN PUERTO RICO