Genetic Mapping of Biomass Production in Tetraploid Alfalfa
- Joseph G. Robinsa,
- Diane Luthb,
- T. Austin Campbellc,
- Gary R. Bauchanc,
- Chunlin Hec,
- Donald R. Viandsd,
- Julie L. Hansend and
- E. Charles Brummer *b
- a USDA-ARS Forage and Range Research Lab., Logan, UT 84322
b Raymond F. Baker Center for Plant Breeding, Iowa State Univ., Ames, IA 50011; E. Charles Brummer current address: Center for Applied Technologies, Univ. of Georgia, Athens, GA 30602
c USDA-ARS Soybean Genomics and Improvement Lab., Beltsville, MD 20705
d Dept. of Plant Breeding and Genetics, Cornell Univ., Ithaca, NY 14853
Biomass production represents a fundamental biological process of both ecological and agricultural significance. The genetic basis of biomass production is unknown but asssumed to be complex. We developed a full sib, F1 mapping population of autotetraploid Medicago sativa (alfalfa) derived from an intersubspecific cross that was known to produce heterosis for biomass production. We evaluated the population for biomass production over several years at three locations (Ames, IA, Nashua, IA, and Ithaca, NY) and concurrently developed a genetic linkage map using restriction fragment length polymorphism (RFLP) and simple sequence repeat (SSR) molecular markers. Transgressive segregants, many of which exhibited high levels of heterosis, were identified in each environment. Despite the complexities of mapping within autotetraploid populations, single-marker analysis of variance identified 41 marker alleles, many on linkage groups 5 and 7, associated with biomass production in at least one of the sampling periods. Seven alleles were associated with biomass production in more than one of the sampling periods. Favorable alleles were contributed by both parents, one of which is from the M. sativa subsp. falcata germplasm. Thus, increased biomass production alleles can be gleaned from unadapted germplasm. Further, the positive quantitative trait locus (QTL) alleles from the parents are partially complementary, suggesting these loci may play a role in biomass production heterosis.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2007.