Abstract
Higher caffeine content and cup beverage bitterness considerably depreciated the commercial value of Coffea canephora Pierre (CAN) compared with C. arabica L (ARA). Wild caffeine-free species like C. pseudozanguebariae Bridson (PSE) offer the opportunity to produce new CAN varieties containing little or no caffeine. F1 plants resulting from a PSE x CAN cross, and BC1 individuals, derived from the first backcross generation (PSE x CAN) x CAN) were produced. In order to assess flowering phenology and yield traits in F1 and BC1 hybrids, six morphological characters including flowering time, pollen viability (PV), fructification rate (FR), seed set (SSET), flower number per node (NFN) and 100-bean weight (W100) were studied under environmental conditions in Cote d'Ivoire. The results showed that F1 plants flowered only in February while, for BC1, 20% and 80% of the plants flowered in January and February, respectively. The fertility and productivity parameters in F1 were much lower than those of the parental species. Indeed, 5-13% of the pollen was viable depending on the year, the fructification rate was 9.6%, seed set was 1.02, the 100-bean weight was 8 g and seven flowers developed per node. These parameters did not differ from those recorded for the BC1 hybrid. Following multiple linear regression analysis, significant and positive relationships were found between the fructification rate and seed set (r=0.54) and between flower number per node and 100-bean weight (r=0.26), while no significant correlations were computed between these four characters (FR, SSET, NFN and W100) and pollen viability. The principal component analysis revealed that the three principal factors of variability among the BC1 offspring were female and male fertility as well as yield. Interestingly, two groups of plants (fertile and productive) were identified among the BC1 individuals and will be used for subsequent backcrosses.