Synthesis of new interspecific triploid hybrids from natural AB germplasm in banana (Musa sp.)

The release of new sweet-acid banana cultivars resistant to black leaf streak, Sigatoka leaf spot and Fusarium wilt is important for domestic markets in tropical and subtropical countries. Common current breeding strategies consist of selecting tetraploid AAAB hybrids directly from crosses between AAB sweet-acid cultivars pollinated with AA clones carrying disease-resistance genes. However, this crossing pathway is hampered by low gamete fertility and the rare occurrence of desired 2N gametes on the AAB female side (N=3X=33 chromosomes). We propose an alternative pathway which aims to create new triploid hybrids directly from AB landraces. Natural AB clones are sterile but their AABB tetraploid counterparts obtained by colchicine treatment are fertile. This gamete fertility was made profitable in crosses with AA and BB accessions to generate AAB and ABB hybrids. We present here agronomical results of various progenies involving an in vitro synthesized tetraploid 'Kunnan' (AABB) and several AA and BB clones. These first results suggest the very high potential of this new strategy for the release of wellperforming new hybrids combining higher productivity, disease resistance and better fruit quality. Hybrids with a high added-value, produced in this way, could be made available for evaluation within the ProMusa network.