Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2004
Publication Date: November 4, 2004
Citation: Johnson, J.M., Jaradat, A.A., Barbour, N.W., Vankempen, S.J. 2004. Inter- and intra-specific variation for lignin content in roots of annual medicago spp. [CD-ROM] ASA-CSSA-SSSA Annual Meeting Abstracts. Madison, Wisconsin. Technical Abstract: Root biochemistry was studied over two years in 30 accessions of four annual Medicago spp. These accessions were selected for their adaptation to conditions in the upper Midwest as potential crops for long-term C sequestration. Two factors, derived from six biochemicals (suc, glu, total soluble sugars (tss), cellulose (cel), starch and total lignin (tl)), accounted for 86.0% of total variation in the roots' chemical composition of all accessions, whereas the first three variables explained 65.6% of total variation in tl content of all species. Mean tl was 93.4 mg/g in M. lupulina, 137.1 mg/g in M. orbicularis, 173.0 mg/g in M. polymorpha and 200.0 mg/g in M. rotata. It was negatively correlated with suc (r=-0.78, p=0.01), tss (r=-0.73, p=0.01) and cel (r=-0.65, p=0.05), and positively correlated with glu (r=0.43, p=0.05) and was the only biochemical to discriminate among species. However, when species x year interaction was considered, cel, tss and suc, in decreasing order, were more powerful in discriminating among species. Years and species accounted for 34.0 and 30.0% of variation in tl content, respectively. The low contribution of species was due only to the significantly variable response of M. polymorpha over years, without which, species accounted for (41.0%) of total variation in tl. M. rotata is a candidate crop for high biomass production and C sequestration.