Magnitude of Exploitable Heterosis for Yield and Quality Traits of Coffee (Coffea arabica L.) Hybrids as Affected by Distant Parents in Origin and Morphology in Ethiopia

Abstract

This study was conducted to generate information on the effects of distant parents in origin, growth habit and leaf tip color on the magnitude of standard heterosis (SH) in Coffea arabica L. hybrids for yield and quality in 34 hybrids generated from 15 parents in Ethiopia. The results showed distant parents in origin produce hybrids with higher standard heterosis in magnitude in a greater number of hybrids. It was observed that 16 and 11 out of 17 between and within region hybrids exhibited standard heterosis ranging from 0.8 to 52.8% and from 3.58 to 44.95%, respectively, for fresh cherry yield. In comparison, hybrids obtained from crossing distant parents in all factors (origin, growth habit and leaf tip color) registered the highest magnitude of SH, which ranged from 21.05% (clean coffee yield) to 52.80% (fresh cherry yield) with mean SH of 36.64 and 28.95% for fresh cherry and clean coffee yield, respectively. For coffee quality parameters, the effect of parents’ leaf tip color on the magnitude of heterosis was observed to be more important than the parents’ geographical origin. Five out of six hybrids having both parents green leaf tip color (Kaffa x Kaffa and Kaffa x Sidamo) exhibited SH of 1 to 16% for the overall coffee quality. These hybrids also exhibited positive and significant SH (14 to 33%) for 6 out of 8 coffee quality parameters. The results of this study suggested the importance of including distant parents in all possible factors to produce greater number of high yielding hybrids with highest magnitude of standard heterosis in Ethiopia. The results further revealed the possibility of improving target region coffee quality through selection of parents on the basis of their leaf tip color for crossing regardless of their origin.

Keywords: Distant Parents; Growth Habit; Hybrids; Leaf Tip Color; Origin; Standard Heterosis