Cytological studies of African cultivated rice, Oryza glaberrima

Abstract

African cultivated rice, Oryza glaberrima Steud., was cytologically characterized by using both karyotype analysis and molecular cytology. The somatic chromosomes resemble those of Asian cultivated rice, Oryza sauva L., in general morphology, although some minor differences were noted. Multicolor fluorescence in situ hybridization (McFISH) with chromosomes detected one 45s (17s-5.8s-25s) ribosomal RNA gene locus (45s rDNA) and one 5s ribosomal RNA gene locus (5s rDNA) in the chromosome complement. The 45s rDNA and 5s rDNA loci were physically mapped to the distal end of the short arm of chromosome 9 and to the proximal region of the short arm of chromosome 11 respectively, as in O. sativa. Based on the cytological observations and the physical map of the rDNA loci, the chromosomal organization of O.glaberrima and O. sativa seems to be very similar.

The African Rice Oryza glaberrima Steud: Knowledge Distribution and Prospects

“…Genes influencing these traits and showing signs of ancient selection are considered domestication genes. Among the species which composes the complex sativa (Table1), the two domesticated species and cultivated in Africa are distinguished from the wild species by the following characteristics which represent the syndrome of domestication (Lolo, The hypothesis of parallel lines of domestication process of the two cultivated species has been confirmed by cytological studies (Fukui et al, 1991;Ohmido et al, 1995) cited by Sweeney and McCouch (2007). The two cultivated species have been classified within the group of A-genome species but formed separate clusters within it, as shown by results from isozymes and molecular marker studies (Ge et al, 1999;Ren, 2003).…”

Molecular Mapping of a Pollen Killer Gene S29(t) in Oryza Glaberrima and Co-Linear Analysis with S22 in O. Glumaepatula

“…O. glaberrima, however, is abandoned largely because of its poor agronomic performance compared to high yielding O. sativa cultivars. The two cultivated species derive independently from different ancestor species but possess same AA genome (Morishima et al, 1963;Ohmido et al, 1995;Pental et al, 1985). Comparing with O. sativa, O. glaberrima is resistant to relevant pests, such as rice yellow mottle virus, blast, African rice gall midge, Heterodera sacchari, leafhopper (Attere et al, 1983;Khush, 1989;Reversat et al, 1995;Silue et al, 1991) and tolerance for stress, e.g.…”

Allelic data revealing interrelatedness in rice species (Oryza sativa, Oryza glaberrima, Oryza barthii) and the interspecific hybrids (NERICA)

“…Clustering of O. sativa with O. glaberrima have been reported by Semon et al (2005) that major portions of chromosomes of O. glaberrima could not be distinguished from O. sativa. The position and organization of two ribosomal RNA gene clusters (45sr DNA and 5sr DNA) were found to be similar in the chromosome of the two species (Ohimido and Fukui, 1995). Today, both O. glaberrima and O. sativa are commonly grown in mixtures by farmers in upland and rainfed environments.…”