Effects of inbreeding on growth and yield of oil palm

The effects of inbreeding were studied in three oil palm (Elaeis guineensis Jacq.) trials in the Democratic Republic of Congo (Congo). In selfings, marked inbreeding depression was observed for yield of fruit bunches, mean bunch weight and bunch number, but there was little effect on bunch composition. Most vegetative measurements were significantly affected by selfing, but leaf production rate and leaf area ratio were unaffected. Sib-crossing had less depressive effect than selfing, and in some families sib-crosses were superior to outcrosses. Where selection needs to be done within inbred families, our study suggests that leaf area ratio and bunch composition would be useful criteria.