Topography of the Cotyledon Surfaces and Adjoining Seed Coat of Chickpea (Cicer arietinum L.) Genotypes Differing in Milling Performance

Abstract

Milling of pulse seeds generally refers to dehulling (decortication or seed coat removal) and splitting (division of the two cotyledons) to produce split seeds, known as dhal. Reduction of whole seeds or dhal to flour, in comparison, is generally termed “grinding” for pulses. Many pulses are consumed as dhal, including desi chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), lentil (Lens culinaris L.), field pea (Pisum sativum L.), pigeon pea (Cajanus cajan L.), mungbean (Vigna radiata L.), black gram (Vigna mungo L.), and hyacinth bean (Lablab purpureus L.). Hence, ease‐of‐milling is an important quality attribute of pulse species that are commonly dehulled or split prior to consumption. Seed structure and the surface topography at the junctions between seed coat and cotyledons have the potential to influence the varietal differences observed in the ease of milling. The epicuticular wax surfaces of six genotypes of chickpea differing in ease of milling were examined by scanning electron microscopy to evaluate whether the physical attributes of seed coat and cotyledon surfaces could be involved in adhesion. Differing epicuticular wax patterns were observed for each of the six genotypes. The possible roles these patterns play in genotypic differences in ease of milling are discussed.