Phenotypic Diversity of Ethiopian Barleys in Relation to Geographical Regions, Altitudinal Range, and Agro-Ecological Zones: As an Aid to Germplasm Collection and Conservation Strategy

Abstract

Data on 51 accessions of landrace barley from an Ethiopian collection were analyzed for variation of six morphological traits. Shannon- Weaver diversity indices (H′) were calculated for traits, populations, geographical regions, altitude classes, and agro-ecological zones. Mean diversity (H′) for Ethiopia was 0.71 ± 0.09. Polymorphism was high for rachilla hair type (H′= 0.92) and aleurone color (H′= 0.90) and relatively low for some traits, e.g., caryopsis type (H′= 0.29). The chi-square (x2) analysis displayed that some regions, such as Welega, Tigray, Gojam, had significant phenotypic differences for most traits. Analysis of variance showed no significant differences either among regions (except aleurone color) or among altitude classes as well as among agro-ecological zones but attributed most of the variance to populations. A clinal pattern of variation was observed in rachilla hair type and row number with altitude, the latter also in relation to north-south direction. The highest mean diversity index (H′= 0.77 ± 0.07) was recorded for areas ranging in altitude from 2000 to 2500 m. A decline in mean diversity with increasing elevation was also noted. Although no obvious patterns of diversity with respect to major agro-ecological zones were revealed, zones with fairly high estimates of variations (H′= 0.74 ± 0.11) were identified. Principal components analyses showed that 28% of the variance was explained by black lemma/blue aleurone/black seed and white phenotype and further corroborated character correlations revealed by diversity indices. Based on the characters considered and populations evaluated, sites in Gonder/Tigray (representing the north), Welega (in the western), and Arsi (representing central and eastern regions), with due consideration to agro-ecological and altitudinal parameters, may serve as appropriate locations for in situ conservation.