Genomic in situ hybridization identifies genome donor of finger millet (Eleusine coracana)

Abstract

Eleusine coracana, commonly called finger millet, is an important cereal of semi-arid regions, cultivated in parts of Africa and India for its grain. It is reported to be an allotetraploid with a chromosome number 2n = 4x = 36, and diploid species E. indica, with chromosome number 2n = 2x = 18, is considered to be one of its genome donors. In situ hybridization of the E. coracana genome with the genomic DNA of various diploid species of the genus confirmed that E. indica is one of the genome donors to E. coracana and that E. floccifolia is another genome contributor to this allotetraploid species. In situ hybridization also showed a close genomic relationship between 4 diploid species, E. indica, E. floccifolia, E. tristachya and E. intermedia, and also between these and tetraploid species E. coracana. The common genomic in situ hybridization (GISH) signals of the genomic DNA of E. indica and E. tristachya on 15–18 chromosomes of E. coracana clearly indicated that these 2 species have a close genomic similarity. GISH on 25–27 chromosomes of E. coracana withthe genomic DNA of E. intermedia and cross in situ hybridization signals on the chromosomes of E. coracana with genomic DNA of E. intermedia and E. indica or E. intermedia and E. floccifolia has showed that E. intermedia may be an intermediate species of E. indica and E. floccifolia.