A genomic assessment of Vicia villosa Roth: Evaluation by flow cytometry, canonical discriminant analysis, and replicated cDNA microarray analysis

Determining the ploidy of plant germplasm has been suggested as a first step before initiating breeding or genetic studies in species. Flow cytometry and root tip chromosome squashing methods were employed to assess 45 accessions labeled Vicia villosa available through the USDA germplasm. Large-scale differences in DNA amounts were observed and were hypothesized to be due to chromosomal size variability as opposed to ploidy differences. This revealed the incidence of species misidentification of two V. villosa accessions to be Vicia pannonica. All the V. villosa accessions were observed to be diploid and have similar DNA amounts.; Secondly, it is necessary to gain insight into the magnitude of variability present in the species. Thirteen morphological and agronomic traits were measured on the 45 Vicia accessions in field studies at Urbana, IL for two years. The multivariate data set was analyzed by canonical discriminant analysis (CDA) in combination with a clustering procedure. The canonical variates indicated that fall and spring measurements of the leaf and stem, and C:N ratio are the most differentiating traits among the accessions. The canonical variates were used to cluster the accessions into 4 subgroups based upon the differentiating traits. Plant breeders can use the information on variation among Vicia accessions and focus on traits of particular significance.; The final research objective is to determine statistically significant expressed genes in hairy vetch that are also biologically significant to traits hypothesized to be integral in hairy vetch improvement. The RNA of four targets were hybridized to 142 cDNA clones of biotic stress genes and gene sequences of soybean that were robotically spotted onto aminosilicated slides. The microarray data was analyzed using the individual fluorescence intensities to fit two statistical models with a mixed model analysis of variance using Proc Mixed in SAS. Ninety-seven of the 142 gene sequences (68%) were differentially expressed in at least one of the target comparisons. Eighty-three of the sequences (58%) were differentially expressed in hairy vetch. Among these are two sequences that encode for proline-rich proteins, which are abundant in cell wall structures and are involved in plant development.