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.

"changhae" is a new Hibiseus variety developed by a mutation breeding by using a gamma ray irradiation. O dred seeds ofthe or iginal variety, "Suminokura", grown in a breeding field in the Namyangju, Gyeonggi Province were irradiatedwith a 100 Gy gamma ra

One-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (1D SDS-PAGE) was used to determine whether it would provide improved resolving power of hordein proteins concomitant with improved identification of Korean barley cultivars and germplams. This system gave rapid and reproducible separations of hordein polypeptides. Total fourteen of clear and easily scorable subunits were identified in Korean barley cultivars and germplasms and their polymorphic constitutions could provide biochemical genetic information in progeny analysis and endosperm quality improvement in barley breeding programs. Each hordein polypeptides residing in B, C, and D hordein pattern designations were scored to prepare a cultivar catalogue of protein patterns. On the basis of this character, 7 hordein polypeptide patterns were constructed from 108 barley cultivars and experimental lines. The molecular weight of hordein subunits in Korean barley cultivars and experimental lines varied in the range of 98 to 48 kDa. In contrast, less polymorphic hordein polypeptides were found in the low protein barley lines including malting barleys than those found in Korean barley cultivars and experimental lines