Author
ROBINS, JOSEPH - IOWA STATE UNIVERSITY | |
LUTH, DIANE - IOWA STATE UNIVERSITY | |
Campbell, Travis | |
Bauchan, Gary | |
He, Chunlin | |
VIANDS, DON - CORNELL UNIVESITY | |
BRUMMER, CHARLIE - IOWA STATE UNIVERSITY |
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/27/2006 Publication Date: N/A Citation: N/A Interpretive Summary: Despite the ecological and agronomic importance of increased biomass production there has been virtually no effort in alfalfa to examine its underlying genetics. Crosses between genetically different alfalfa plants which display hybrid vigor can be utilized to increase biomass production. To address these issues, we developed a mapping population of alfalfa by crossing two types of alfalfa; cultivated alfalfa with purple flowers and a very close relative, subspecies falcata with yellow flowers; that were known to produce vigorous hybrids. We grew the population at three locations (Ames, IA; Nashua, IA; and Ithaca, NY) and collected biomass production data over a period of three years at Ames and Nashua and two years at Ithaca and discovered several plants that were very high in biomass production compared to the parents. We developed genetic linkage maps of the genomes of both parents using molecular markers and discovered several molecular markers which were associated with biomass production and hybrid vigor. Scientists and the alfalfa seed industry are very interested in using these molecular markers to increase the yield of alfalfa. Technical Abstract: Biomass production represents a fundamental biological process of both ecological and agricultural significance. Heterosis for biomass production occurs upon crossing particular genotypes. The genetic basis of biomass production, and of heterosis, is unknown. To address these issues we developed a full sib, F1, mapping population of autotetraploid alfalfa by crossing two genotypes of M. sativa subsp. falcata by M. sativa subsp. sativa that were known to produce heterosis. We developed genetic linkage maps of the genomes of both parents using RFLP and SSR molecular markers. We grew the population at three locations (Ames, IA; Nashua, IA; and Ithaca, NY) and collected biomass production data over a period of three years at Ames and Nashua and two years at Ithaca. Transgressive segregants, many of which exhibited high levels of heterosis, were identified at each sampling period. Using single-marker analysis to identify QTL associated with biomass production and heterosis, we found QTL associated with these traits being contributed by both parents. These results suggest that both germplasm sources (M. sativa subsps. sativa and falcata) contain genomic regions that contribute to increased biomass production and that these were partially complementary, suggesting loci important for heterosis. |