Microclimate and development of Coffea canephora intercropped with Carica papaya: measures to mitigate climate change

Intercropped systems with Conilon coffee might provide a better environment for coffee production. The aim of this study was to assess the microclimate and development of Conilon coffee intercropped with papaya trees. Papaya was planted with spacing of 3.20 x 2.40 m. The coffee trees were planted after eight months, with spacing of 3.20 x 1.60 m, in-between papaya trees (in the same row). The measurements were taken 0, 40 and 80 cm away from the coffee plants, both in the north and south direction. Concomitantly, an adjoining full sunlight coffee system (not intercropped) was also assessed. The measurements included atmospheric parameters (temperature, irradiance, and relative humidity) and vegetative parameters for the coffee plants (leaf area, relative chlorophyll index, length of plagiotropic branches, length of orthotopic branches and number of nodes) in three periods of the year. The intercropped system of Conilon coffee and papaya trees led to a decrease in both irradiance and temperature, and higher means of relative humidity during daytime in all the periods assessed, which contributes to a better environment for coffee cultivation. The shadow provided by papaya trees in the coffee plants contributed to a higher leaf area but did not affect neither the growth of both plagiotropic and orthotopic branches, nor the number of nodes and the etiolation. The intercropped system of Conilon coffee and papaya trees may be potentially used as a farming system to mitigate climate change.

Correlação entre crescimento e produtividade do cafeeiro em função do regime hídrico e densidade de plantio / Correlation between coffee plant growth and yield as function of water supply regime and planting density

Este trabalho foi desenvolvido em área experimental da Universidade Federal de Lavras com o objetivo de avaliar as características de crescimento e de produção do cafeeiro irrigado e não irrigado e estudar a correlação dessas entre si e com densidades de plantio e regimes hídricos. O delineamento experimental utilizado foi em blocos casualizados em esquema de parcela subdividida com quatro repetições. Os tratamentos constaram de três regimes de irrigação: (i) irrigações quando a tensão da água no solo atingiu valores próximos a 20 kPa, (ii) irrigações quando a tensão da água no solo atingiu valores próximos a 60 kPa e (iii) uma testemunha não irrigada, os quais foram distribuídos em três densidades de plantio: (i) 2.500 plantas ha-1 (4,0 m x 1,0 m), 10.000 plantas ha-1 (2,0 m x 0,5 m) e 20.000 plantas ha-1 (1,0 m x 0,5 m). Foram estimadas as correlações fenotípicas entre as características de crescimento (altura da planta, diâmetro de caule e número de ramos plagiotrópicos) com a produção do cafeeiro (litros de café por planta) e produtividade (sacas de café beneficiado ha-1) em dois anos. Nas duas primeiras safras de lavouras irrigadas, a altura das plantas apresentou maior correlação com a produtividade em relação às demais características, já o número de ramos plagiotrópicos teve correlação positiva com a produtividade somente na primeira safra. Cafeeiros conduzidos em sistema de plantio adensado foram mais responsivos à irrigação.

This study was carried out in an experimental area of the Universidade Federal de Lavras aiming to evaluate coffee plant growth and yield characteristics and study the correlation between coffee plant growth and yield as function of water supply regime and planting density. An experimental design with randomized blocks and split parcels with four replications was used. Three irrigation regimes were applied as treatment: (i) Irrigation whenever soil water tension approaches a value near 20kPa; (ii) Irrigation whenever soil water tension approaches a value near 60kPa; and a non irrigated control treatment. These three treatments were applied to three planting densities; (i) 2,500 plants ha-1 (4.0 m x 1.0 m), 10,000 plants ha-1 (2.0 m x 0.5 m) e 20,000 plants ha-1 (1.0 m x 0.5 m). Correlation among plant growth characteristics (plant height, steam diameter, and number of plagiotropic branches) and coffee bean production (liters per plant) and beneficed coffee bean yield (60kg bags ha-1) were estimated. Along the first two harvest period, plant height and yield showed the highest correlation value found. Only for the first harvest period, the number of plagiotropic branches per plant was positively correlated to yield. Coffee plants growing under higher planting density showed a better response to irrigation.

Influencia de la época del año en la respuesta in vitro del cafeto Coffea canephora P Var Robusta / Influence of the time of year on the in vitro response of Coffea canephora P Var Robusta coffee trees

Generalmente, las plantas responden de manera diferenciada a las técnicas de cultivo in vitro, dependiendode la respuesta inicial del cultivo y su capacidad embriogénica del genotipo, el estado fisiológico de la planta yel explante, la edad de la planta donante, los factores físicos, los reguladores del crecimiento y las condiciones nutricionales, así como el cambio estacional. De aquí que el presente estudio se realizó con el objetivo de evaluar la influencia de la época del año en que fue tomada la fuente de los explantes en la respuesta in vitro de genotipos de Robusta. Se realizaron muestreos durante todos los meses del año, los explantes foliares fueron cultivados en un medio contentivo de las sales minerales de Murashige y Skoog (1962) y 0,5 y 2,0 mg.L-1 de 2,4-D y kinetina, respectivamente. Se observó que la época del año en que se tomó la muestra ejerció un marcado efecto en la respuesta de los explantes de los genotipos evaluados. Para las condiciones estudiadas resultó favorable la toma de las muestras foliares en los períodos mayo-junio, enero-febrero y noviembre-diciembre, dados los bajos índices de actividad enzimática peroxidasa, oxidación fenólica y contaminación fúngica, así como un elevado porcentaje de formación de callos y mayor contenido de proteínas totales presentes en los mismos. Se determinó que la actividad enzimática peroxidasa pudiera constituir un importante marcador en la etapa inicial de selección de las muestras.

Plants generally respond in different ways to in vitro cultivation techniques, depending on the crop’s initial response and the embryogenic capacity of its genotype, the physiological state of the plant and the explant, the age of the donor plant, physical factors, growth regulators, nutritional conditions and seasonal change. The present study was thus aimed at evaluating the influence of the time of year during which the source of explants was taken on the in vitro response of Robusta genotypes. Samples were taken during each month ofthe year, foliar explants were cultured in a medium containing Murashige and Skoog mineral salts (1962) and 0,5 and 2,0 mg.L-1 2,4-D and kinetine, respectively. It was observed that the time of the year when a sample was taken exercised as marked effect on the response of the explants from the genotypes evaluated. Taking foliar samples during May-June, January-February and November-December proved favourable in the conditions studied here given the low indices of peroxidase enzymatic activity, phenol oxidation and fungal contamination, as well as the high percentage of callus formation and their greater total protein content. It was determined that peroxidase enzymatic activity could constitute an important marker during the initial stage of selecting samples.