Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2001
Publication Date: March 25, 2001
Technical Abstract: Fertile cross compatibility between Tripsacum dactyloides and Zea species offers unique opportunities for bi-directional genomic enrichment. Tripsacum genetic contributions to maize can lead to important grain nutritional improvements, new resources for resistance to stresses, and apomictic reproduction. Similarly, maize derived genes are expected to enhance Tripsacum for such characters as seed set and germination. Comparative genomics and marker assisted breeding involving Tripsacum requires constructing a genetic map with markers well distributed over the 18 Tripsacum linkage groups. This study tested the suitability of maize and sorghum derived DNA primers to detect PCR generated markers for a diploid T. dactyloides F2 mapping population. Amplification by 79 maize SSR primers was 63% with similar results obtained using primers designed to 26 maize ESTs. Surprisingly, many Tripsacum amplicons were significantly higher in molecular weight when compared to their maize counterparts. Sorghum SSR primers required modified reaction conditions to result in approximately 55% amplification success. SSLP type markers useful for mapping were infrequent, a consistency in polymorphism reductions often observed when attempting cross-taxa PCR based methodologies. Increased difficulty in discovering informative PCR primers for Tripsacum SSLPs could be attributed to transmitting the non-polymorphic allele(s) from the heterozygous parental genomes to the F1 parent. Consequently, cleaved amplified polymorphic sequence (CAPs)and sequence analysis were investigated as alternative strategies to determine if useful polymorphism identification could be significantly enhanced. The efficacy of the three methods for developing the Tripsacum genetic map will be presented.