Wild Crop Relatives: Genomic and Breeding Resources

Abstract

M. acuminata (contributing genome A) and M. balbisiana (contributing genome B) are the ancestors of today’s banana and plantain cultivars, which are important food crops in the tropics. They together with other related wild species belong to the genus Musa that includes five sections, namely Eumusa , Rhodochlamys , Callimusa , Australimusa , and Ingentimusa . Demographic history and dispersal mechanisms explain their genetic diversity, both among populations and across geographical regions. Although diploid Musa wild species produce seeds, they are difficult to conserve. Hence, their genetic diversity is preserved through vegetative propagation or through tissue culture in test tubes. Plant morphology, as well as biochemical and DNA markers, has been used for identifying Musa commercial cultivars, wild species, and subspecies. Wild diploid species are widely available in most Musa genebanks and used in breeding programs due to their host plant resistance to a broad range of pathogens and pests. Some available DNA marker systems for Musa genetic enhancement are the result from research on both M . acuminata and M. balbisiana accessions. A bacterial artificial chromosome (BAC) library from the wild banana “Calcutta 4” has become a valuable tool for Musa genomics research worldwide.