Correlation and Path Coefficient Analysis of Quantitative Traits in Some Wollega Coffee (Coffea arabica L.) Landrace in Western Ethiopia

Dawit Merga

doi:10.7176/jees/9-4-01

Abstract

Arabica coffee is cash crop which plays great role in providing foreign exchange for Ethiopia. The twenty six coffee genotypes (22 accessions with four standard checks) were used during field experiment using Randomized Complete Block Design (RCBD) with three replications. The experiment was conducted with the objective to determine the association among quantitative traits of some wollega coffee genotypes. Quantitative data was taken for 23 traits of which 22 showed significant difference among coffee genotypes. Coffee bean yield had positive phenotypic and genotypic correlation with growth parameters such as Plant height (PH), height up to first primary branch (HFPB), total node number (TNN), diameter of main stem(DM), number of primary branches (NPB), number of bearing primary branches (NBPB), percentage of bearing primary branches (PBPB) and canopy diameter (CD). From path coefficient analysis of CD, fruit width and fruit thickness showed negative direct effect on yield. This implies that indirect selection of these traits via other traits for yield improvement is momentous. Average length of primary branch (ALPB), HFPB, TNN and NBPB had positive direct effect and positive phenotypic correlation (rp=0.18, 0.14, 0.36, 0.50 respectively) with green bean yield. This revealed that selecting plants with high performance in these traits will lead to selection of plants with high yield. Thus, priority should be given for these traits during breeding program for yield improvement. Keywords: -Coffea arabica L., genotypic correlation, path coefficient, phenotypic correlation and traits DOI : 10.7176/JEES/9-4-01 Publication date : April 30 th 2019

Highlights

The agricultural based Ethiopian economy is highly dependent on Arabica coffee
Data taken during the study were:Plan height (PH):- Height from the ground level to the tip of the main stem Height up to first primary branch (HFPB):- Measurement of height above the ground up to the first primary branch Total node number of main stem (TNN): - Counts of number of nodes on the main stem
Internodes length of the main stem (IL):- Computed as (TH–HFPB)/total node number (TNN)-1, where TH = total plant height, HFPB =height up to first primary branch, TNN = total number of main stem nodes Diameter of the main stem (DM):- Measured the diameter of the main stem at five cm above the ground using digital caliper Number of primary branches (NPB):- Counted number of primary branches per main stem tree Number of secondary branches (NSB):- Counted number of secondary branches per tree Average length of primary branches (ALPB):- It was measured from the point of attachment to the main stem to the apex in cm

Summary

Introduction

The agricultural based Ethiopian economy is highly dependent on Arabica coffee. Around 31 percent of the country's foreign exchange income comes from this single commodity crop (FAO, 2014). As a result of this, Ethiopia is Africa’s largest Coffee producer and the world’s fifth largest Coffea arabica L. exporter next to Brazil, Vietnam, Colombia and Indonesia (ICO, 2016) It provides significant employment opportunities in rural areas and sustains the livelihood of around 15 million in Ethiopia (Davis et al, 2012; ICO, 2016). Despite the abundance of coffee genetic diversity and center of origin for Coffea arabica L., the productivity per unit area remained very low in Ethiopia with average national clean coffee yield of 670 kg ha-1 (CSA, 2017). To overcome this problem, selecting traits that contribute directly and indirectly for yield improvement is prerequisite to identify high yielding genotypes. Such improvement depends on both genotypic correlation and phenotypic correlation of traits (Johnson et al, 1955)

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