ORGANIZATION OF AMERICAN STATES - AGRO FORESTRY RESEARCH PROJECT

Development of sustainable land-use systems on degraded tropical pastures in Belize, Central America, as a model for Mesoamerica and the Caribbean.

Performance of photosynthesis of hot pepper (Capsicum spp.) was analyzed during field surveys between 2000 and 2004 in Belize in cooperation with German experts from the Albert-Ludwigs-University, Freiburg. The light dependency of photosynthesis of various tropical trees including Papaya and hot pepper was determined with a mini-PAM (LCA-4, portable photosynthesis unit) characterizing the Electron Transport Rate (ETR) at different Photosynthetic Active Radiation (PAR) levels. The electron transport pattern is one way for the measurement of photosynthesis, also indicating the light requirements of plants for sufficient biomass production and development. Surprisingly, data of the electron transport rate of habanero pepper indicated that adult leaves of hot pepper plants might be adapted to shading. This finding is contrary to the existing traditional method to cultivate habanero pepper in sunny places. Therefore, the idea was born to design a habanero based agro-forestry research project for more investigation.

It seems important to pass on this new knowledge of 'shade tolerance' of habanero pepper plants to farmers producing them in Belize. The current knowledge, however, is not sufficient to estimate the consequences of reduced light exposure of habanero hot pepper plants on their yield or quality level. Evaluation of yield and quality responses of habanero pepper plants under shading in field trials is essential. It must be investigated whether habanero hot pepper yield can be increased significantly by growing the plants under shaded conditions, compared to the current practice to grow them in full light.

The Agro-Forestry Research Project in Belize (funded by the Organization of American States), is a first step to continue field experiments for data availability and experiences on hot pepper plant development in intercropping systems. Within the already achieved project results, field data assessments confirm that habanero hot pepper plants might need less light exposure for optimal development than expected so far. This is more or less in accordance with Alvino et al. (1994), who stated that their results confirm that leaf photosynthesis of pepper (results refer to bell pepper!) is ranked in a lower position among the C3 plants, as indicated in the review by Jones (1983). On the other hand, Alvino et al. (1994) reported that both low irradiance and water stress can also reduced the leaf CO2 exchange rate in bell pepper.

Nevertheless, additional follow-up research is essential in order to investigate in more detail the yield and quality responses of hot pepper under shading compared to exposure to full light.