Diversity and mapping studies on cereal genomes
Abstract
Three different molecular marker technologies were used to determine relatedness in one Eleusine (Finger millet) and two Sorghum (Sorghum) collections. A very low level of polymorphism was detected in the finger millets, but the results allowed each line to be distinguished. The different Eleusine species could be easily identified by DNA marker technology and intraspecific levels of diversity appear to be higher in E. floccifolia than E. indica. Species E. coracana, E. indica and E. tristachya form a close genetic assemblage within the Eleusine, while E. floccifolia and E. compressa seem to be more distant relatives. A group containing 34 Chinese sorghums was analysed. Lines from the northeastern provinces of Heilongjing and Liaoning seem to share a higher number of alleles with each other. Improved varieties were found to be more diverse than landraces, suggesting the recent use of foreign materials in Chinese breeding programs. A collection containing 84 sorghum lines representative of the world collection was also analyzed. Both race and geographical origin were found to be correlated with relatedness. Wild sorghums were shown to have few novel alleles, suggesting that they would be poor sources of germplasm diversity. The results also indicated that Chinese sorghums are a narrow and distinctive group that is most closely related to race bicolor. A comparison of DNA marker technologies indicated that inter simple sequence repeat amplification (ISSR) is a relatively fast, inexpensive and informative technique. The discovery of synteny among the grasses suggests great value for the use of heterologous probes in fine mapping. The rootless (rtl) gene of maize was mapped relative to maize, oat and rice RFLP probes. The rice probe RZ995 was the closest non maize probe, locating approximately 10 cM from rootless. Maize probes UMC 154 and UMC 92 were the closest flanking probes, covering a 6 cM interval.
Degree
Ph.D.
Advisors
Bennetzen, Purdue University.
Subject Area
Genetics|Molecular biology
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