Leaf structure is one of the important agronomic traits. A rolled leaf mutant was induced from an ethyl methane sulfonate (EMS)-treated japonica rice, 'Koshihikari'. The rolled leaf mutant showed phenotypes of reduced leaf width and leaf rolling. In addition, several abnormal morphological characteristics were observed, including dwarfism, defected panicle, delayed germination, and lower seed-setting. Microscopic analysis revealed that the number of small veins was decreased and the sizes of adaxial bulliform cells were reduced in the mutant leaves. The genetic study with two F2 populations from the crosses of the rolled leaf mutant with 'Koshihikari' and Milyang23 suggested that the mutant phenotype might be controlled by a single dominant gene.

"Seoanl" is a new japonica rice variety developed from a cross between Namyang9, a line of lodging tolerance and adaptable to reclaimed saline area, and Gyehwa7, a line of good-quality, adaptable to reclaimed saline area and high yield by the rice breeding team of National Institute of Crop Science, RDA, in 2005. This variety has about 131 days of growth duration from transplanting to harvesting in central plain area, and mid-western coastal area in Korea. It is about 73 cm in culm length and tolerance to lodging. It has also semi-erect pubescent leaf blade and slightly tough culm with good canopy architecture. The number of panicles per hill of Seoanl is slightly more than that of Hwaseongbyeo. Seoanl was susceptible to major diseases, blast, bacterial blight and viruses, and insect, brown plant hopper. This variety has lower amylose content of 18.8% and better palatability of cooked rice than those of Hwaseongbyeo. The milled rice yield performance of this variety is about 5.60MT/ha in local adaptability test for three years. Seoanl would be adaptable to central plain area and mid-western coastal area of Korea.

The response of dissolved oxygen (DO) concentrations caused significant change in root number, root length, coleoptile length, shoot length and leaf age of seedlings. The genotypic difference in the effect of DO also highly significant (P<0.01) for all of the seedling traits. The number and length of root were extremely inhibited at the condition of 0.39~pm0.09 DO concentration. While the coleoptile elongated markedly in the lowest DO concentrations, the shoot did not develop. The root growth was improved slightly at the 1.39~pm0.27mg L-1 , however, there were no difference among genotypes at these two low DO concentrations. As the DO concentration become higher, the growth of root and shoot was improved remarkably. Root number, root length and shoot length was significantly different between 20~;and~;30~circC in DO rich and normal conditions, the development of those traits were apparently accelerated in high water temperature, however those traits of seedlings in DO deficiency were not different between the two temperatures except for shoot length. On the other hand the coleoptile length was not affected by the stagnant water temperature; it was stimulated by the low DO concentration. The competition of DO was greater as the seedling density was increased in the stagnant water, therefore the seedlings grown under high density have long and white coleoptiles, and the growth of roots and shoots was retarded severely.

Cold acclimation of plants is a highly active process resulting from the expression of a number of physiological and metabolic adaptations to low temperature. Major metabolic changes in carbohydrates, protein, nucleic acids, amino acids, and growth regula