Browsing by Author "Gezahagne, Melkamu"

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    Species Distinctiveness in Trifolium quartinianu11l A. Rich and T. steudneri Schweinf. (!egulIlinosae)
    (Addis Ababa University, 2004-07) Gezahagne, Melkamu; Hanson, Jean (PhD); Dagne, Kifle (PhD)
    Morphological, breeding and cytogenetic parameters were used to assess species distinctiveness among accessions of T. qllartillialllllu, T. stel/dueri and a distinct morphotype of T. steudueri (Accession 9452). The morphological characterizations showed that there was a considerable level of inter- and intraspecific variation among the accessions. The distinct 1l10rphotype exhibited a unique pattern of morphological characters. Hierarchical cluster analysis generated nine clusters and showed that the distinct morphotype was relatively closer to accessions ofT. quartillialJulll than it was to T. steudlJeri. In fact, it stood even off the cluster it is grouped in. Principal component analysis was also performed and generated seven components to which the characters showed respective correlation. Some level of interspecies compatibility was observed among some accessions of the involved taxa on the basis of interspecific hybridization. The results of the preliminary experiments showed that there were allowing conditions for the interspecific hybridization. Successful pollen tube growth, and compatibility between the time the pollen was shed and the stigma was receptive were some of the pre-fertilization barriers broken by some of the species combinations. Successful hybridization was, hence, attained in some of the intra- and interspecific crosses. Each of the species and the distinct morphotype was observed to have a diploid chromosome number of 16. There was no difference in the chromosome number among these taxa. Chromosome number, hence, could not be used to identifY and differentiate among the taxa. Key Words: Ti-ifoliul/l quartinianulll, Trifolium steudneri, distinct morphotype (Accession number 9452), Accessions, morphology, hybridization, cytogenetics.