Submitted to: Sugar Y Azucar
Publication Type: Abstract Only
Publication Acceptance Date: 6/17/1998
Publication Date: N/A
Technical Abstract: Related species of Saccharum are crossed to elite sugarcane cultivars for genetic improvement of sugarcane. Selection of true hybrids is difficult due to the lack of morphological and molecular markers. We are developing species-specific polymerase chain reaction (PCR)-derived markers for use in hybrid selection. By using generic primers P1/P2, DNA products were amplified from the 5S ribosomal DNA spacer region of two elite sugarcane cultivars and several related species including S. officinarum, S. spontaneum, S. giganteum, Erianthus spp., Miscanthus sinensis, maize, and sorghum. These PCR products exhibited limited length polymorphisms, and Southern blot experiments indicated that PCR products from various taxa did not always cross hybridize. The products were cloned into a plasmid vector and sequenced. A dendrogram from multiple sequence alignment divided these taxa into five groups: S. officinarum, S. spontaneum, and elite sugarcane cultivars in Group I; the three cytotypes (2n = 30, 60, 90) of S. giganteum in Group II; Erianthus spp. in Group III; sorghum cultivars in Group IV; and maize cultivars in Group V. Two M. sinensis clones appeared divergent: clone Zebra was more closely related to the sugarcane group, while clone IMP3057 was more closely related to Erianthus spp. and S. giganteum. Clones of Erianthus spp. and S. giganteum also contained unique DNA sequences which were absent from other species. We will discuss the possibility of using these unique sequences in screening of true hybrids from interspecific crosses.