It was previously pointed out that mutation is the ultimate source of variation. Adequate variation is needed for plant breeding if there is a limitation in natural genetic resources. When the ionizing radiation has been known to cause chromosomal and genomic alternations, it is widely used for inducing mutagenesis. The electron beam as an ionizing radiation is the principal physical mutagens that induces mutation and effectively used in plant breeding. Since dose-response relationships of electron beam in plant species are rarely known, we investigated the seed germination rate and early seedling growth of irradiated seeds of creeping bentgrass (Agrostis palustris Huds., cv Penn-A1) with various electron beam irradiating conditions (1, 1.3, 2 MeV at both 0.03 mA and 0.06 mA with dose of 100 Gy (Gray) and 0.03, 1, 1.3, 2 MeV at 0.03 mA with dose of 200 Gy, respectively) using electron accelerator at Korea Atomic Energy Research Institute. The growth parameters in terms of shoot length, primary root length, and secondary root length showed similar response between 0.06 / 1 (mA / MeV) at 100 Gy and 0.03 / 0.3 (mA / MeV) at 200 Gy. Bentgrass seed germination was mainly affected by the intensity of irradiated dose (Gray). Germination rate was lowered as the irradiated dose increased. On the other hand, early seedling growth was mainly governed not by the dose of radiation but by voltage.

A new black seed coat soybean variety, “Socheong” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Socheong was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Peking which was tolerant to lodging and with small seed size. The preliminary, advanced and regional yield trials for evaluation and selection of this variety were carried out from 2002 to 2006. It has determinate growth habit, white flower, brown pubescence, brown pod color, black seed coat, green cotyledon, elongated flattened seed shape, oval leaf shape and small seed size (15.7 grams per 100 seeds), and it was 3 days later in maturity than the check cultivar Cheongjakong. Socheong was higher, in the seed quality of sucrose and total sugar contents (6.8 and 8.2%) and isoflavone contents (1,754 ㎍/g) than the check cultivar. Futhermore, it has good characteristics for mechanical harvest, such as lodging tolerance, pod shattering and stem diameter. It also has been identified to have resistance to soybean mosaic virus symptom which was the troublesome soybean diseases. The average yield of Socheong was 2.21 ton per hectare in the regional yield trials carried out in four locations of Korea among seven locations from 2004 to 2006, which was 5 percent lower than the check cultivar Cheongjakong.

A new black seed coat soybean cultivar, “Heugmi” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Heugmi was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Milyang 68, which was middle maturing, resistant to lodging and SMV and with middle seed size and yellow cotyledon. The preliminary, advanced and regional yield trials for evaluation and selection of this cultivar were carried out from 2001 to 2006. It has determinate growth habit, purple flower, brown pubescence, black pod color, black seed coat, green cotyledon, spherical seed shape, oval leaf shape and middle seed size (24.8 grams per 100 seeds), and it was 2 days earlier in maturity than the check cultivar Cheongjakong. Heugmi was better in the seed quality of crude protein contents, sucrose and total sugar contents than the check cultivar. It also has been identified to have resistance to SMV which was the troublesome soybean diseases. The average yield of Heugmi was 2.53 ton per hectare in the regional yield trials carried out in seven locations of Korea from 2004 to 2006, which was 8 percent higher than the check cultivar Cheongjakong.

“Hwanggeumchal”, a new covered waxy cultivar derived from the cross between “Chalssalbori” and “Milyang 65” with waxy endosperm and early maturing cultivars, respectively was developed at Honam Agricultural Research Institute (HARI), NICS, RDA, 2006. The origin of “Hwanggeumchal” is “Suwon 403” (SB942090-B-B-B-42-1). The initial cross was made in 1994 and the selected line showed a high yield and good quality characteristics under yield trial test in 2003. “Suwon 403” consistently performed well for three years (2004-2006) from the four locations of regional yield trial (RYT) in Korea and released as “Hwanggeumchal”. The characteristics of “Hwanggeumchal” were the following: rate I growth habit, green leaf and stem, compact spike and with long rough awns. The heading date was April 30 in upland and April 28 in paddy field, which was 1 and 4 days later than that with check cultivar, “Seodunchalbori”. The culm length was 81 cm which was 3 cm shorter than those with check cultivar. It showed spike length of 4.5 cm and 633 spikes per m2, 64 grains per spike, 27.6 g of 1,000-grain weight and 632 g of test weight. It showed stronger winter hardiness and higher resistance to barley yellow mosaic virus (BaYMV) than those with check cultivar. It had yellow aleurone and showed higher water absorption, expansion rate and total phenol content than those of check cultivar, but lower protein, β-glucan content and pearling rate. The average yield of the pearled grain in the RYT was 4.04 ton ha-1 in upland and 4.12 ton ha-1 in paddy field, which was 10% higher and 4% lower than that of the check cultivar, respectively. This cultivar would be suitable for the area above the daily minimum mean temperature of -8℃ in January in Korean peninsula.