Comparisons of Earlier- and Later-formed Pods of Pigeonpeas (Cajanus cajan (L.) Millsp.)

Abstract

On branches of indeterminate cultivars of pigeonpea, flowering begins at the basal nodes and proceeds acropetally; in morphologically determinate cultivars, flowering begins on the apical racemes and proceeds basipetally. In cultivars of both types, within the racemes flowering proceeds acropetally. Under normal conditions more pods are set from earlier-formed flowers than from later-formed flowers, many of which are shed. Consequently the earlier-formed pods are found at the more basal nodes of racemes, and in indeterminate cultivars at the more basal nodes on the branches. The average weight of earlier and later-formed pods, collected from the basal and apical nodes of the racemes or of the branches, was similar; so was the number of seeds per pod, the weight per seed and the nitrogen content of the seeds. This pattern differs from that found in most herbaceous legumes, where later-formed pods are smaller, and indicates that pigeonpeas set fewer pods than they are capable of filling. This behaviour may be related to the intrinsically perennial nature of pigeonpeas. The comparison of the weights of earlier- and later-formed pods could provide a simple screening procedure for identifying plants with an annual nature among existing cultivars or in breeders' lines