Distribution of discretely scored descriptors in a pure line faba bean (Vicia faba L.) germplasm collection

Abstract

Because of the partially insect cross-pollinated nature of faba bean (Vicia faba L.), ICARDA maintains two types of faba bean germplasm collections. The ILB (International Legume Faba Bean) collection consists of the original germplasm accessions as received, usually heterogeneous and heterozygous. From this another collection of faba bean pure lines (BPL) has been derived through a process of cyclic single plant progeny selection. The frequency distributions of eight (stipule spot pigmentation, leaflet size, lodging, intensity of streaks, pod angle/attitude, pod shape, pod color at maturity, and seed shape) of 22 discretely scored descriptors showed significant variation. Other descriptors tended to follow the normal scores associated with the cultivated varieties of the ICARDA region. For the eight descriptors with sufficient variation, frequency distributions were calculated separately for eight regional groupings (the Nile Valley, West Asia, North Europe, southern Europe, eastern Europe, North Africa, Ethiopia and the Indian subcontinent). The most important regional variation was smaller leaflet sizes in West Asia and northern and southern Europe, and higher susceptibility to lodging in Ethiopia. Pod and seed descriptor regional variation closely followed known preferences for seed size and pod length which are based on different regional uses of faba bean.