Studies in the pollen morphology of Cajanus cajan(L.) Millsp. and its wild ally Atylosia W. & A.

Studies in the pollen morphology of 13 cultivars ofCajanus cajan, a cultivated legume of Africa and Asia,and six species of Atylosia, a wild ally ofC. cajan, were conducted with light microscope andscanning electron microscope, with a view to assess interrelationship betweenthe wild and cultivated species. There is a striking resemblance among thepollen features of Cajanus cajan and fiveAtylosia species, namelyA. albicans, A. lineata,A. platycarpa, A. scarabaeoidesand A. volubilis. Pollen grains in all these species are3-zonocolporate with thickened colpi margins, and the exine surface isreticulate with circular, slightly elongated or irregular lumina. The mergerof these Atylosia species into the genusCajanus finds support also in pollen features. However,A. marmorata (an Australian species) shows distinctlydifferent pollen features from all of the above species by having smallerpollen grains, by the absence of thickened colpi margins and by havingreticulation with elongated large brochi with narrow muri. Interestingly,A. scarabaeoides, another Australian species but alsowidely distributed in Africa and Asia, does not show pollen morphologicalaffinity with A. marmorata, and is closer toCajanus cajan.