Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/1998
Publication Date: N/A
Technical Abstract: Buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.) is a drought-tolerant, warm-season, perennial forage grass grown throughout the semi-arid tropics. It is a highly polymorphic species with recombination levels adequate for linkage analyses. The objective of this research is to construct a detailed genetic map of buffelgrass to investigate the molecular basis of apospory and serve as a framework map for marker facilitated breeding in perennial forage grasses. Eight hundred, sixty-two heterologous probes from cDNA and genomic DNA libraries across the Poaceae, as well as 443 homologous probes from a pistil-specific cDNA library, were evaluated. Four hundred, sixty-five polymorphic probes were mapped in 87 F1 hybrids, yielding linkage maps for the female and male parents with 409 and 300 SDRFs, respectively. The female map contained 47 linkage groups and covered 3464 cM, while the male map contained 42 linkage groups and covered 2949 cM. Average marker spacings on the respective maps was 10.8 and 11.0 cM. Repulsion- versus coupling-phase ratios of markers revealed that most linkage groups have some or complete preferential chromosome pairing, while a few have complete random pairing. Two homologous probes were found to flank the genomic region for apospory. Fine mapping is underway to increase the map resolution in this region and facilitate map-based cloning of the apospory gene(s). Implications of the map toward forage breeding programs and apomixis research will be discussed.