GENOTYPE AND ENVIRONMENTAL-EFFECTS ON NATTO SOYBEAN QUALITY TRAITS

Production of small-seeded natto soybean [Glycine max (L.) Merr.] has increased in eastern Canada during the past decade, Improved natto qua lity characteristics are important for maintaining and increasing this market. This study was conducted to examine environmental and genotyp e x environment effects on quality characteristics. Two data sets were used for statistical analysis: seven lines grown at five locations in 1989 and 1990 (Data Set 1) and fifteen lines grown at the same five l ocations in 1993 and 1994 (Data Set 2). Quality characteristics import ant in natto production were measured: small-seed fraction, percentage of seeds with impermeable seed coats, water uptake, seed shape, and l evels of the seed constituents, Ca, oil, and sugar, Genotypes were sig nificantly different for most traits in both data sets, Location effec ts were not significant for any quality traits, Year effects were sign ificant only for seed shape and sugar levels in Data Set 2. Year x loc ation interactions were often significant, but no patterns were appare nt in these interactions. Genotype x environment interactions were oft en significant, but these variance components were usually an order of magnitude smaller than the main effects of genotype, These results in dicate that it is possible to develop natto soybean cultivars that are broadly adapted to the short-season areas of eastern Canada.