Abstract
The performance of F1 hybrid plants derived from crosses between traditional varieties of Coffea arabica of Latin America with a "wild" collection of Sudan - Ethiopian origin were studied for yield, fertility and bean weight. Sudan Ethiopian material possesses resistance to certain diseases, and possibly, better beverage quality. The objective of this breeding programme is to widen the very narrow genetic base of Central American coffee, even while increasing quality and productivity. The hybrid plants were obtained from two factorial crosses made and evaluated in two locations. They were compared in the two field trials using the six maternal lines as controls. Observations were taken on vegetative characters, annual and cumulated yield, dry weight of 100 beans, extent of early abortion as measured by the fraction of 'peaberries' and post-zygotic ovule fertility as measured by the fraction of mature no-floating berries in water (FF). The F1 hybrid population were compared to the populations of maternal lines for the aforementioned variables. An index-based selection was done in the hybrid populations employing three traits, yield, 100-bean weight and the post-zygotic fertility ( FF). The performance of the selected hybrids was then compared to those of the best parental 'control' lines in each trial. The hybrid populations yielded 22 - 47% more than the maternal lines, but hybrids showed significantly more sterility than the parental control lines. Selection in the hybrid populations using the three selected traits led to significant genetic gain for yield and dry weight of 100 beans, and insignificant gain for fertility ( FF). When selected on the basis of fertility alone, increase in yield and 100-bean weight were not obtained within the hybrid populations. By applying selection on yield and 100-bean weight, the selected hybrids produced 11 - 47% higher yields than the best line along with significantly higher or identical 100-bean weight and performed identically for fertility. The yield performance of hybrids between the Latin American material and the "wild" Sudan - Ethiopian material calls for further selection effort for improving beverage quality.