Flooding stress causes a significant reduction in soybean yield. The development of flood-tolerant cultivars is an effective way to minimize yield loss due to flooding. Information on candidate genes for flooding tolerance is useful for developing tolerant lines. The
objective
of this study was to identify potential candidate genes for flooding tolerance in soybean by integrating the results of a quantitative trait locus analysis and RNA sequencing. A total of 19 genes showed good amplification in capillary electrophoresis and were further analyzed through a reverse transcription quantitative polymerase chain reaction (qRT-PCR); two of these genes showed differential expression among tolerant and susceptible lines. The expression of Glyma.12g030900 and Glyma.10g050300 in leaf and root tissues, respectively, was higher in several tolerant lines than in the susceptible lines under flooding stress. The chlorophyll index of the tolerant lines was also consistently higher than that of the susceptible lines over two years, supporting the qRT-PCR results. This study provides useful information on flooding tolerance in soybeans.

‘Joongmo2004’, a winter wheat (Triticum aestivum L.) cultivar was developed by the National Institute of Crop Science, RDA. It was derived from the cross ‘Bacanora88/Keumkang//Keumkang’ during 1996. ‘Joongmo2004’ was evaluated as ‘Iksan320’ in advance yield trial test in 2006. It was tested in the regional yield trial test between 2007 and 2009. Its heading date was April 26 in upland and April 23 in paddy filed conditions, and Maturity date was June 5 in upland and June 4 in paddy field, which were similar to Keumkang, respectively. It showed 830 in number of spikes per m², 35 of grain number per spike, 44.9g of 1,000 grain weight, and 806g of test weight. ‘Joongmo2004’ showed moderate to fusarium graminearum (Scab) in test of specific character although ‘Keumkang’ is susceptible to scab. ‘Joongmo2004’ had higher flour yield (75.5%) than ‘Keumkang’(72.5%). ‘Joongmo2004’ showed similar ash (0.42%), lower protein content (12.3%), SDS-sedimentation volume (43.0 ml) and gluten content (10.3%) than ‘Keumkang’ (0.42%, 13.1%, 57.8ml and 10.8%, respectively). It showed higher lightness (89.97), redness (-1.38) and yellowness (10.76) in flour color than ‘Keumkang’ (89.61, -1.15 and 9.46, respectively). ‘Joongmo2004’ exhibited lower hardness (3.50N), similar springiness and higher cohesiveness of cooked noodles (0.92 and 0.65) compared to ‘Keumkang’ (4.54N, 0.93, and 0.63, respectively). The average grain yield in the regional yield trial was 517 kg/10a in upland and 534 kg/10a in paddy field, which were 11% lower and 3% higher than that of the check cultivar, ‘Keumkang’, respectively.

‘Joongmo2003’, a winter wheat (Triticum aestivum L.) cultivar was developed by the National Institute of Crop Science, RDA. It was derived from the cross ‘SW86054/Keumkang’ during 1997. ‘Joongmo2003’ was evaluated as ‘Iksan318’ in advance yield trial test in 2006. It was tested in the regional yield trial test between 2007 and 2009. Its heading date was April 24 in upland and April 21 in paddy filed conditions, which was two days earlier than those of the check cultivar ‘Keumkang’, respectively, and maturity date was June 4 in upland and June 2 in paddy field, one or two days earlier than those of ‘Keumkang’, respectively. ‘Joongmo2003’ showed resistance to winter hardiness and pre-harvest sprouting, which lower withering rate on the low ridge (0.3%) and rate of pre-harvest sprouting (18.5%) than ‘Keumkang’ (9.2 and 25.8%, respectively). ‘Joongmo2003’ showed similar protein content (13.2%), lower SDS-sedimentation volume (54.0 ml) and higher gluten content (11.7%) than ‘Keumkang’ (13.1%, 57.8ml and 10.8%, respectively). It showed higher lightness (89.85) of flour and noodle dough sheet than ‘Keumkang’ (89.81 and 80.28, respectively). ‘Joongmo2003’ exhibited similar hardiness (3.84N), springiness and cohesiveness of cooked noodles (0.92 and 0.63) compared to ‘Keumkang’ (4.54N, 0.93, and 0.63, respectively). The average grain yield in the regional yield trial was 555 kg/10a in upland and 485 kg/10a in paddy field, which were 4% and 7% lower than those of the check cultivar, ‘Keumkang’, respectively.