INFLUENCE OF TIME OF PLANTING ON YIELD AND GRAIN QUALITY OF BEAN GENOTYPES GROWN ON AN ANDOSOL IN THE WESTERN HIGHLANDS OF CAMEROON

Determining the best combinations of variety choice and planting date may be crucial for farmers in view of optimising bean yields. A study was conducted to assess the agronomic performance of selected dry bean (Phaseolus vulgaris L.) lines when planted sequentially under rain fed conditions in the Western Highlands of Cameroon (WHC). Forty two introduced lines and three local checks were used, namely, 15 bush lines, 15 semi climber lines, and 15 climber lines. Three sequential dates of planting were chosen at 15 days intervals starting from 15th of September 2007. Delaying bean planting up to the 15th of October resulted in a 50 to 77% yield reduction. The highest losses were recorded by climber and semi-climber lines which have a relatively longer growth cycle. Consequently, grain quality also deteriorated as the weight of 100 seeds dropped by 11.4, 15.8 and 3.3% for bush, semi- climber and climber lines, respectively. The causative factors were likely soil moisture deficit coupled with insect pests damages to grains during formation and towards maturity. Disease incidence on the crop varieties was mild and scores ranged from resistant (1-3) to tolerant (4-6). In this environment, it is better to plant beans up to 1st October; beyond this date, it may be advisable for farmers to go for a high yielding bush variety. Climber and semi-climber varieties yielded at least 25% higher than bush ones under prevailing environmental conditions.