Crossbreeding East African Highland Bananas: Lessons Learnt Relevant to the Botany of the Crop After 21 Years of Genetic Enhancement

East African highland bananas (EAHB) were regarded as sterile. Their screening forfemale fertility with “Calcutta 4” as male parent revealed that 37 EAHB were fertile. Thiswas the foundation for the establishment of the EAHB crossbreeding programs by theInternational Institute of Tropical Agriculture (IITA) and the National Agricultural ResearchOrganization (NARO) in Uganda in the mid-1990s. The aim of this study was to assessthe progress and efficiency of the EAHB breeding program at IITA, Sendusu in Uganda.Data on pollinations, seeds generated and germinated, plus hybrids selected between1995 and 2015 were analyzed. Pollination success and seed germination percentagesfor different cross combinations were calculated. The month of pollination did notresult in significantly different (P= 0.501) pollination success.Musa acuminatasubsp.malaccensisaccession 250 had the highest pollination success (66.8%), followed by thecultivar “Rose” (66.6%) among the diploid males. Twenty-five EAHB out of 41 studiedfor female fertility produced up to 305 seeds per pollinated bunch, and were thereforedeemed fertile. The percentage of seed germination varied among crosses: 26% for2x×4x, 23% for 2x×2x, 11% for 3x×2x,and 7% for 4x×2x. Twenty-seven NARITAhybrids (mostly secondary triploids ensuing from the 4x×2x) were selected for furtherevaluation in the East African region. One so far –“NARITA 7”– was officially released tofarmers in Uganda. Although pollination of EAHB can be conducted throughout the year,the seed set and germination is low. Thus, further research on pollination conditions andoptimization of embryo culture protocols should be done to boost seed set and embryogermination, respectively. More research in floral biology and seed germination as wellas other breeding strategies are required to increase the efficiency of the EAHB breedingprogram