Mihyangbyeo, a new japonica aromatic rice (Oryza sativa L.) was developed by National Honam Agricultural Experiment Station (NHAES), RDA in 1998. It was derived from the three-way cross among Seomjinbyeo of the disease resistance and high yielding lines,

“Sobibyeo” is a new japonica rice cultivar developed from a cross betw een Hwayeongbyeo and YR13604Acp22 line by the rice breeding team of National Honam Agricultural Experiment Station (NHAES), RDA, in 1999. This cultivar has a large grain and about 119

To evaluate the efficiency of anther floating culture according to the maturing group, the varietal difference and classification of fifty varieties was conducted in N6 liquid medium containing 1mg l-1 NAA, 0.25 mg l-1 kinetin. The efficiency of callus induction was widely ranged from 0 to 113.4%, but the mean callus induction was not significantly different among maturing groups. The efficiency of anther floating culture showed the highest variation in early-maturing group among three maturing groups. The varieties with the best callus induction were Sambaegbyeo and Jinbuolbyeo, while the recalcitrant variety was Obongbyeo in early-maturing group. The efficiency of plant regeneration showed the highest trends in late-maturing group among three maturing groups. The fifty varieties were classified into three groups (distance=0.78) by cluster analysis based on the callus formation and plant regeneration. Group including only two varieties, Shinunbongbyeo and Sambaegbyeo had the excellent androgenic efficiency, and the medium efficiency of Group was included thirty-six varieties. Whereas twelve varieties, including three Tongil varieties were fell into the bad efficiency of Group. Especially, Tongil varieties containing Japonica rice, Obongbyeo were the recalcitrant genotypes for the anther floating culture.

An efficient system of rice microspore culture could contribute to the production of genetically modified rice. The microspores were isolated by mechanical or shed methods. The number of microspores per 100 anthers isolated at uninucleate stage was higher than (or similar to) those at binucleate stage in isolation method with pestle or spatular, but microspore divisions were not easily observed on both stages. On the other hand, pollen division in shed pollen culture was observed more frequently at uninuclear than at binuclear stage. Cold pretreatment at 10~circC for 10 days resulted in the best multicellular division to produce microcalli at 12.5% efficiency in shed microspores. Heat shock at 33~circC for one hour before or after pollen shedding enhanced cell division and callus formation. Out of twelve green regenerants, two were haploids and ten were diploids based on the chromosome analysis of root tips. The size of stoma was 12m m in haploids and 15 ~mu~textrmm in diploids determined by scanning electron microscope (SEM).

Transgenic plants from hypocotyl segments of buckwheat were produced with the Agrobacterium strain LBA4404 harboring the binary vector pBI121 containing chimeric genes of neomycin phosphotransferase II (npt II) and β -glucuronidase (gus). Two weeks after co-cultivation with Agrobacterium, most of the hypocotyl segments gradually became brown and died on the selection medium containing 100mg/~ell of kanamycin. Plants regenerated from the hypocotyl explants grown on selection medium were GUS-positive in the leaf, stem and vascular tissues by histochemical assay, and varied in gus activity (440-2568 pmol, 4-MU/mg protein) by fluorimetry. The plants showing GUS activity were confirmed of containing GUS and NPT-II genes by polymerase chain reaction (PCR). Within 3 months, transgenic buckwheat plants were able to obtained from the hypocotyl segments.