Major QTLs associated with green stem disorder insensitivity of soybean (Glycine max (L.) Merr.).

Green stem disorder (GSD) is one of the most serious syndromes affecting soybean (Glycine max) cultivation in Japan. In GSD, stems remain green even when pods mature. When soybean plants develop GSD, seed surfaces are soiled by tissue fluid and seed quality is deteriorated during machine harvesting.

Community shifts of soybean stem-associated bacteria responding to different nodulation phenotypes and N levels.

The diversity of stem-associated bacteria of non-nodulated (Nod(-)), wild-type nodulated (Nod(+)) and hypernodulated (Nod(++)) soybeans were evaluated by clone library analyses of the 16S ribosomal RNA gene. Soybeans were dressed with standard nitrogen (SN) fertilization (15 kg N ha(-1)) and heavy nitrogen (HN) fertilization (615 kg N ha(-1)). The relative abundance of Alphaproteobacteria in Nod(+) soybeans (66%) was smaller than that in Nod(-) and Nod(++) soybeans (75-76%) under SN fertilization, whereas that of Gammaproteobacteria showed the opposite pattern (23% in Nod(+) and 12-16% in Nod(-) and Nod(++) soybeans).