Chickpea (Cicer arietinum L.) is one of the most important food legumesrngrown all over the world. In Ethiopia, chickpea is among the most importantrnfood legumes both in terms of area coverage and volume of production. Thernproduction of chickpea is important not only in terms of human and animalrnnutrition but also in terms of ecological sustainability through symbioticrnnitrogen fixation. Despite the importance, productivity of chickpea isrnconstrained at least in part by production problems related to the inherentrnlow-yielding potential of the local cultivars, production without applicationrnof adequate inputs including fertilizers and post-harvest insect pest damagernparticularly adzuki bean beetle (Callosobruchus chinensis L.).rnEthiopia is known as one of the centers of secondary diversity forrnchickpea. Genetic resources with proven performance for better symbioticrnnitrogen fixation, phosphorus uptake and use efficiency and adzuki beanrnbeetle resistance are limited for focused utilization in chickpea breedingrnprograms. Characterization and evaluation of genetic make-up of thernEthiopian chickpea germplasm accessions is, therefore, essential to designingrneffective breeding programs.rnGenetic diversity and population structure of 155 chickpea genotypesrnwere studied using 33 microsatellite (SSR) markers. A series of field andrnlaboratory experiments were also undertaken in 2009-2010 in Ethiopia torncharacterize and evaluate Ethiopian chickpea germplasm for attributes ofrnsymbiotic nitrogen fixation, phosphorus use efficiency and adzuki beanrnbeetle resistance. The field studies for symbiotic nitrogen fixation andrnphosphorus use efficiency were undertaken at Ambo and Ginchi while thernadzuki bean beetle resistance study was conducted in entomologyrnlaboratories at Debre Zeit, Holetta and Ambo in Ethiopia. The tests forrnsymbiotic nitrogen fixation and phosphorus uptake and use efficiency werernconducted with 155 genotypes and 130 genotypes were tested for adzukirnbean beetles resistance. Randomized complete block designs with 4rnreplications for symbiotic nitrogen fixation, 2 for phosphorus uptake and usernefficiency and 3 for resistance to adzuki bean beetle were used. Therndifference technique, with a non-nodulating reference genotype wasrnemployed to estimate nitrogen fixation and the balance method was used tornestimate phosphorus uptake and use efficiency.rnMolecular analysis of variance showed variation of 73% within and 27%rnbetween populations. Introduced genotypes had higher polymorphismrn(70.27%) than the local accessions (36-57%). Collections from Shewa,rnHarargie, W. Gojam and S. Gonder regions showed the second higherrnpolymorphism (50-57%) than the rest of the local accessions (36-45%).rnAccessions from adjoining eco-geographical origins mostly showedrntendencies for more genetic similarity than those from far isolated origins.rnCluster analyses at the molecular level grouped the genotypes into fivernclusters. The first cluster (C1) constituted accessions from Arsi, the second (C2)rnfrom Gojam and Gonder, the third (C3) from Harargie and E. and N. Shewa,rnthe fourth (C4) from W. Shewa, Tigray and Wello regions and the fifth (C5) allrnimproved genotypes. Improved Kabuli and Desi types fell into a distinctrncluster (C5) regardless of the difference in seed types. Analysis of variance of symbio-agronomic characters, phosphorusrnuptake and use efficiency and adzuki bean beetle resistance showedrnsignificant differences among the genotypes, locations and genotype byrnlocation interaction effects for a number of traits. Genotype by phosphorusrnlevel interaction effects were non-significant except in a few cases.rnA number of landraces superior to introduced genotypes were identifiedrnfor attributes of symbio-agronomic characters except for seed size where thernbest genotypes were all from exotic sources. The amount of fixed nitrogenrnranged from 13-49% in foliage, 30-44% in grain and 28-40% in total abovernground biomass. Grain yield performance varied from 31-70 g 5 plants-1 andrnseed size from 82-288 g/1000 seeds. The top 5% best accessions for totalrn(shoot + grain) nitrogen fixation include Acc. Nos. 41222, 41029, 41021,rn41074, 41075, 41129, 41320 and 41026. There were also some otherrngenotypes which had better fixations either in their shoots (e.g. 41103) orrngrains (e.g. 207734). Two introductions from ICRISAT, namely ICC 5003 andrnICC 4973, were also among the top 5% best fixers of nitrogen in their shoot.rnThe best assimilators of fixed nitrogen were Acc. Nos. 41115, 207659,rn219799, 207150, 41277, 41113 and 207894.rnThe application of phosphorus fertilizer increased a number ofrncharacters including symbiotic nitrogen fixation. Yield increments of 15% atrnAmbo and 17% at Ginchi were recorded due to application of phosphorus.rnThe top 5% best efficient, responder genotypes for grain yield include Acc.rnNo. 41274, 41111, 207742, 207563, 207763, 231328, ICC 19180 andrn41114. Three of these accessions, namely 41274, 207563 and 41111, alsornrepeated best performances as efficient, responder genotypes for biomassrnweight. Other efficient, responder genotypes for biomass weight include: Acc.rnNos. 207743, 41015, 41066, 41185 and Ejere.rnComplete resistance to adzuki bean beetle was not observed among therngenotypes but Acc. Nos. 41320, 41289, 41291, 41134, 41315, 207658,rn41103, 41168, 41142, 41174, 41029, 41207, 209087, 231327, 41161 andrn41008 showed partial resistance. Significant progresses were achieved inrngrain yield and seed size from past breeding efforts but the same efforts hadrninadvertently increased seed susceptibility to adzuki bean beetle.rnCluster analysis grouped the genotypes into six cluster for symbioagronomicrncharacters, five clusters in the absence and six clusters in thernpresence of phosphorus, respectively, for attributes of phosphorus uptakernand use efficiency and three clusters for attributes of adzuki bean beetlernresistance. The higher number of clusters when the crop was grown withrnphosphorus may be a manifestation of more genetic diversity due to thernapplication of phosphorus. The limited genetic diversity for responserncharacters to infestation by adzuki bean beetle may imply the need forrncharacterization of additional landraces and exotic genotypes.rnThe Mahalanobisâ€™s D2 statistics mostly showed significant geneticrndistances between clusters constituted local landraces on the one hand andrnintroduced genotypes on the other. This indicated that there were distinctrnmultivariate differences between landraces and introduced genotypes. No clearrninterrelationship was observed between the origins of the landraces within Ethiopia and the pattern of genetic diversity. Different characters had differentrncontribution to the total differentiation of the populations in all the cases.rnThe study on symbio-agronomic traits showed significant positiverncorrelations between a number of characters. Grain yield was positivelyrnassociated with fixed nitrogen assimilation efficiency, shoot, grain, andrnabove ground biomass nitrogen yields and nitrogen harvest index.rnAgronomic characters like grain filling period, pod and seed numbers, shoot,rnand total above ground biomass accumulation, harvest index, grainrnproduction efficiency and biomass production and economic growth ratesrnalso positively correlated with grain yield. Increased nitrogen yield, nitrogenrnharvest index, fixed nitrogen assimilation efficiency and above groundrnbiomass may be more important than the per se concentration of nitrogen inrnplant tissue. Characters like shoot, grain and total biomass nitrogenrncontents and fixation, fixed nitrogen assimilation efficiency, seed size, grainrnfilling period showed higher genetic variation, broad-sense heritability andrnexpected genetic gains from selection.rnThe study on phosphorus uptake and use efficiency revealed significantrnpositive correlations within plant tissue (shoot, seed and biomass) phosphorusrncontents (r = 0.22-0.85), between plant tissue phosphorus contents andrnphosphorus yields (r = 0.22-0.99), within plant tissue phosphorus yields (r =rn0.23-0.89) and within parameters of phosphorus uptake and use efficiency inrna number cases. Grain yield and economic growth and biomass productionrnrates, grain production efficiency, and shoot and biomass dry weight showedrnsignificant positive correlations (r = 0.70-0.99) with phosphorus yieldrnefficiency. Broad sense heritability values ranged from 60-93% and geneticrnadvance values ranged from 4-62% in the absence of phosphorus. Therncorresponding broad sense heritability and genetic advance values in thernpresence of phosphorus ranged from 59-93% and 4-79% in that order.rnIn the study of bruchid resistance seed-related traits (seed size, percentrnseed coat weight and seed weight loss) exhibited larger heritable variationrnthan insect-related traits (number of eggs and adults, days to adultrnemergence, number of uninfected seed and adult recovery). Broad-sensernheritability for seed and insect-related traits varied from 43-76% and 0.20-rn11%, respectively. The corresponding expected genetic gains from selection asrnpercent of mean ranged from 28-42% and 0.01-6% in the same order.rnSignificant positive correlations were found among seed weight loss and threerncomponent characters, i.e. number of eggs and adults emerged and seed size.rnThe results from these series of studies suggests possibilities forrnidentification of chickpea genotypes superior for symbio-agronomicrncharacters, phosphorus uptake and use efficiency and adzuki bean beetlernresistance to the varieties released so far, indicating the need for therninitiation of a planned breeding program. Further implications of thernfindings as regard germplasm collection, conservation and eco-geographicalrnpattern evolution are also discussed.