Multivariate Patterns of Diversity in Ethiopian Barleys

Abstract

ABSTRACTEthiopian barleys (Hordeum vulgare L.) have been collected and described since the early expeditions by Harlan and Vavilov in the 1920s. This paper reviews the literature since then on the diversity and distinctness in this germplasm based on different types of traits (e.g., morphology, isozymes, DNA markers, phenotypic screenings). Most studies have been based on one type of trait at a time. They all indicate that Ethiopian barleys form a very distinct group, with unique diversity in resistance to certain diseases and in morphology, but the average DNA marker or nucleotide diversity is substantially less than barley from the Fertile Crescent. The recurrent suggestions of Ethiopia as a center of origin for barley are discussed; most data support the notion of a “secondary” center. There is a paucity of studies of adaptive traits important to Ethiopian conditions or breeding. The major pattern of adaptation reflects the rainfall patterns, following an altitudinal gradient with increasing rainfall and longer growing season up to about 3000 m altitude. As barleys become later in maturity, they become more susceptible to net blotch, but tolerant to scald and probably frosts during grain maturation. Several improved cultivars have resulted from the pure line selection program initiated about 20 yr ago.