Gibberella fujikuroi species complex (GFSC) was isolated from rice (Oryza sativa L.) seed samples from ten Asian countries and investigated for incidence of GFSC, molecular characteristics, and pathogenicity. Regardless of geographic origin, GFSC was detected with incidences ranging from 3% to 80%. Four species, Fusarium fujikuroi, F. concentricum, F. proliferatum, and F. verticillioides, were found to show an association with rice seeds, with F. fujikuroi being the predominant species. In phylogenetic analyses of DNA sequences, no relationship was found between species, isolates, and geographic sources of samples. Unidentified fragments of the β-tubulin gene were observed in ten isolates of F. fujikuroi and F. verticillioides. With the exception of three isolates of F. fujikuroi, F. fujikuroi, F. proliferatum, and F. verticillioides were found to have FUM1 (the fumonisin biosynthetic gene); however, FUM1 was not found in isolates of F. concentricum. Results of pathogenicity testing showed that all isolates caused reduced germination of rice seed. In addition, F. fujikuroi and F. concentricum caused typical symptoms of bakanae, leaf elongation and chlorosis, whereas F. proliferatum and F. verticillioides only caused stunting of seedlings. These findings provide insight into the characteristics of GFSC associated with rice seeds and might be helpful in development of strategies for management of bakanae.

Rice (Oryza sativa L.) germplasms with an amylose content above 30% were identified by screening 9481 accessions from the Rural Development Administration (RDA) gene bank. The total set of accessions came from 65 countries, including Korea, China, Japan, the Philippines, India, Taiwan, the United States, and Russia. High-throughput near infrared reflectance (NIR) spectroscopy equipped with a fiberoptic probe (700~2500 nm) was used to estimate the amylose content. The amylose contents ranged from 5 to 40% based on NIR spectroscopy; divided into 5% increments, the amylose content of 2820 accessions was found to be between 15 and 20%. To select rice accessions high in amylose, 239 accessions with an amylose content of 30% or greater were selected based on NIR spectroscopy data and cultivated in the field for final selection. Among the 239 accessions selected and cultivated, 151 were deemed agronomically satisfactory. Among the 151 accessions, based on laboratory analysis, 14 had an amylose content higher than 30% and 33 had an amylose content between 28 and 30%. The amylose contents of the reference cultivars Hopum-byeo and Sobi-byeo were 20.7% and 19.9%, respectively. Finally, successful selection of accessions with high amylose content from the large RDA gene bank collection was achieved based on a combination of NIR spectroscopy and laboratory data.