Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Subspecies Specific Markers For Identifying A And B Genomes In The Natural Edible Musa Hybrids

George N. Ude¹ , Michael Pillay² , Abdou Tenkouano³

¹  Department of Natural Science, Bowie State University, 14000 Jericho Park Rd, Bowie, MD 20715, USA

²  International Institute of Tropical Agriculture, Eastern and Southern African regional Center, P.0. Box 7878, Kampala, Uganda

³  International Institute of Tropical Agriculture, Humid Forest Eco-regional Center, BP 2008 Messa, Yaoundé, Cameroon

Several subspecies of Musa acuminata (AA) and at least two genetic forms of M. balbisiana (BB) have played dominant roles in the evolution of the edible Musa clones, but the relationships of the existing clones to their ancestors is not fully understood. . This knowledge will assist breeders to duplicate earlier evolutionary processes that resulted in the present day cultivated varieties. We used fifteen AFLP primer pairs to screen 70 accessions of Musa genotypes for A/B and subspecies genome markers. A 250bp B-genome specific marker was identified and a 330bp marker specific for the M. acuminata subspecies microcarpa group was also observed. The 330bp marker indicated the spp. microcarpa to be the progenitor of the A-genome in the following: dessert bananas (AAA), East African Highland bananas (AAA), plantains (AAB) and Pome (AAB) but not in the cooking bananas (ABB) and Silk (AAB). Furthermore, two B-genome alleles (180 and 182bp) grouped the M. balbisiana accessions into the following three classes: (1) I-63 form, homozygous for the 180bp; (2) Singapuri form, homozygous for the 182bp allele and; (3) HND, MPL, Los Banos, 10852, Butohan 1&2 and Etikehel hybrid forms, heterozygous for the alleles, indicating that they are hybrids of the two homozygous forms. While the 1-63 genetic form of M. balbisiana is indicated to be the donor of the B-genome in Kamarasenge (AB), Kisubi (AB), and plantains, the B-genome in Pome and Silk share marker with the Singapuri form. The cooking bananas (ABB) had the 180 and 182bps in heterozygous state indicating the origin of their B-genomes from diploid hybrids resulting from natural hybridization between the 1-63 and Singapuri forms.