MOLECULAR MARKER-ASSISTED SUGARCANE BREEDING

Authors: Pan, Yong-Bao; Burner, David; Legendre, Benjamin

Submitted to: Inter-American Sugar Cane Seminars Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/6/1998
Publication Date: 9/6/2000
Citation: Pan, Y., Burner, D.M., Legendre, B.L. 2000. Molecular marker-assisted sugarcane breeding. Proceedings of Inter-American Sugar Cane Seminars. 1:31-37.

Interpretive Summary: In sugarcane basic breeding, elite varieties (usually as maternal parents) are crossed with wild species (usually as paternal parents) routinely to transfer superior traits such as high cane and sugar yield, good harvestability, superior regrowth ability after harvest, resistance to diseases and insects, and cold tolerance. A major problem is that self fertilization of the elite varieties also occurs during crossing preventin transfer of the disired traits. Distinct observable physical trait differences are lacking in sugarcane making it difficult to visually distinguish true hybrids from ones which were self pollinated. To circumvent this problem, several DNA markers were developed that were specific to several wild relatives of sugarcane. Using established genetic laboratory procedures we can detect these wild-type DNA markers in the progeny and thus determine that the resulting plants contain traits from both parents. However, no DNA marker has been found that is specific to a more closely related wild species used more often in the basic breeding program. The impact of several other marker systems on sugarcane breeding also are discussed.

Technical Abstract: In sugarcane breeding program intergeneric and interspecific crosses are made between elite sugarcane clones and their related wild species to broaden the genetic base of sugarcane. However, visual selection of hybrids is difficult and is always questionable due to selfing and potential cross contamination. To assist in hybrid selection several species-specific polymerase chain reaction (PCR) primers that target the 5 ribosomal DNA intergenic spacers were developed through PCR, molecular cloning, sequencing, and computer-assisted sequence analysis. We have developed primers Eri3 and Eri4 which were Erianthus spp.-specific, and primers Gig1 and Gig2 which were specific to North American Saccharum including the three cytotypes of S. giganteum (2n =30, 60, and 90). PCR protocols are now available for the selection of hybrids from crosses of elite sugarcane clones with Erianthus spp. and S. giganteum. However, it was difficult to develop S. spontaneum-specific primers at the 5S rDNA locus. The impact of several other molecular marker technologies on sugarcane breeding also were discussed.