Morphological variation among some wellegacoffee (coffea arabica l.) Accessions at haru, west wellega, Ethiopia

Abstract

Arabica coffee (Coffea arabica L.) plays vital role in the Ethiopian economy. Quarter of the people in the country in one way or the other derives their livelihood from coffee production, processing or its trading. Knowledge about extent of genetic diversity among coffee arabica genotypes is important in coffee breeding for various uses. So far, little or no information is generated in genetic diversity of East wellega coffee genotypes in Ethiopia. With the objective of evaluating the extent of genetic variation and association among bean yield and yield related traits. One hundred eleven arabica coffee accessions which were collected from different parts of Eastern wellega and four checks were tested in an augmented designs. The accessions showed significant variation for most traits and test versus control treatments. The variation among the test accessions was significant for most of the characters namely leaf length, leaf width, leaf area, petiole length, bean length, bean width, bean thickness, hundred bean weight, length of first primary branch, stem girth, fruit length, fruit width, fruit thickness and bean yield. Showing the fact that there is real difference among the accessions for these characters. Relatively the phenotypic coefficient of variation were higher than the genotypic coefficients of variation showing the fact that environment elevates the variations. Generally high PCV and GCV were recorded for bean width, hundred bean weight, length of first primary branch and bean yield per unit area. Relatively higher heritability value were observed for leaf length, leaf width, leaf area, bean width, hundred bean weight and fruit length. From the characters studied leaf area, petiole length, bean width, hundred bean weight and bean yield exhibited higher genetic advance showing the fact that the traits can be improved with ease. The D2 analysis grouped the 115 coffee accessions in to twelve clusters. This shows that the accessions are divergent. Principal components (PC1 to PC6) considered eigen value greater than one accounted nearly 71% of the total variation. Bean yield showed positive and significant correlation with length of longest first primary branch (LFPB),stem girth (SG),fruit length (FL), fruit width (FW) and fruit thickness both at phenotypic and genotypic levels showing the fact that high emphasis need to be given for these characters to improve yield at trait basis. Path coefficient analysis showed that length of longest first primary branch which had positive and significant association with yield exert maximum direct effect on grain yield. The second and high direct effects was exerted by fruit width which had also positive and significant association with bean yield showing these two characters should be considered in selection. The Shannon weaver diversity index (H̍ꞌ) analysis of the traits indicated diversity for fruit shape, mature fruit color, branching habit, angle insertion of primary branch, leaf shape and seed shape. This indicates the existence of variability based on their vegetative and bean characteristics. The present study indicated a considerable amount of variability for majority of the characters of interest in coffee Arabica for exploitation. Nevertheless, the need for characterization approach through advanced tools of molecular approaches is suggested.