Morphological discrimination among some aneuploids in soybean (Glycine max (L.) Merr.). I. Trisomies

Abstract

A study of the phenotypes of four primary trisomies (2n + 1) in soybean (Glycine max (L.) Merr.) was conducted. The purpose was to determine whether measurable and consistent phenotypic differences exist between these trisomics and their disomic sibs. These trisomics are designated Tri A, B, C, and D. These trisomic stocks are homozygous but are not isolines. Root-tip squashes of seedlings were used to identify all trisomic and disomic plants. Several plants of each different trisomic type along with an equal number of their disomic sibs were transplanted to the field and randomized within four separate rows. Nineteen different phenotypic traits were measured on all plants.Stepwise discriminant analysis was used to select variables that were good discriminators (0.10 significance level). Each of the four trisomic–disomic comparisons contained a different but overlapping subset of variables that were used in subsequent discriminant analysis. The first discriminatory variable was computed for each trisomic and disomic plant and plotted on a frequency bar chart. Visual interpretation of the chart, along with an F-test, indicates that these trisomics of soybean cannot be reliably distinguished from their disomic sibs on the basis of the phenotypic traits used in this study.Key words: soybean, trisomic, morphology.