Effects of plant population density on the growth, survival rate and yield of common beans (Phaseolus spp.) cultivated under tropical climate

Common beans form a key dietary protein in many developing countries, including the Pacific Island countries. It is an important source of protein for vegetarians or those who cannot afford meat. However, being such an important crop, its yield is affected for several reasons, leading to a major upset for people dependent on it. One of the major issues in tropical climatic regions such as Fiji is the lack of information on the correct spacing to achieve the accepted plant population to increase the yield per given area. Therefore, the current research was carried out to investigate the suitable plant-to-plant spacing in butter and french beans for correct plant population density for maximum yield.

Butter and french beans were selected as a research crop for this experiment with two trials and three replications. Data on plant height, stem girth, leaf chlorophyll content, plant survival rate, number of pods, pod length and pod weight were taken after thirty days of sowing and continued at an interval of ten days until sixty days after sowing.

The experiment results indicate that neither the lower plant-plant spacing nor, the higher plant-to-plant spacing significantly affected the growth and yield of both butter and french bean. However, the plant survival rate under higher plant-to-plant spacing (50x25 cm) was higher; therefore, the higher plant-to-plant spacing is recommended for growing butter and french beans under the tropical climate as it allows the farmers to save around 38% of the seeds while getting similar plant growth and yield.