Visual observation of cowpea pod elongation to predict nitrogen accumulation in immature seeds

Abstract

Cowpea is an important low-cost protein source for millions of people in West Africa. Although mature seeds are the primary food source, fresh green pods are also consumed to survive food shortages before the harvest of main cereal crops. To increase protein intake from green pod consumption, a visual indicator of pod elongation, namely relative pod length, which enables the nitrogen content of immature seeds to be estimated, was developed. This is a simple visual method to ascertain the optimal time for green pod harvesting and is therefore highly practical for local farmers, the primary consumers of green cowpea pods. The nitrogen content of immature seeds was estimated using Fourier transform infrared spectroscopy. This method was also applied to genetic resources to select cowpea accessions with high nitrogen content in immature seeds.

Keywords

• immature pod
• infrared spectroscopy
• nitrogen content
• pod length
• vigna unguiculata