Tocomi-1’, a rice variety with high tocopherol content and a reddish brown color was developed from ‘Dongan’ by a mutation breeding technique using a 120 Gy gamma ray source at the Korea Atomic Energy Research Institute (KAERI). The heading date of this variety was August 12, which was 2 days later than the original variety ‘Dongan’. The culm and panicle lengths of ‘Tocomi-1’ were 80 cm and 20.3 cm, respectively. The number of tillers per hill was 19.1 and the number of spikelets per panicle was 106.3. The ratio of ripened grain was approximately 87.0% and the weight of 1000 grains was 25.4 g. The pericarp of brown rice was reddish brown in color. The total tocopherol content was 1.65 mg/100g, which was higher than that of the original variety (1.09 mg/100g). In addition, the brown rice of ‘Tocomi-1’ contained 8% more total amino acids. The average yield potential of ‘Tocomi-1’ in grain and brown rice was approximately 6.18 kg/10a and 5.15 kg/10a for 3 years, respectively (Registration No. of Plant Protection Wright: 6813).

Hexaploid wheat (Triticum aestivum L.) exceeds about 30% of the world’s cereal production and cultivated over 220 million ha worldwide. Heat stress during the grain filling period gives detrimental effect on crop yields and has emerged as a serious problem throughout the world. Korean wheat cultivars that were released since 1960s were developed for various aims such as winter hardness, earliness, and pest resistance, etc. However, heat stress resistance is an emerging target for wheat breeding nowadays. Selected 11 Korean wheat cultivars (“Baegjoong”, “Dajung”, “Goso”, “Hanbaek”, “Jokyung”, “Joeun”, “Jopum”, “Keumgang”, “Olgeuru”, “Sinmichal”, “Uri”) were exposed to high temperature from DAF (days after flowering) 9~13. In this study, plant responses to heat stress as measured by reduction ratios of total chlorophyll contents, 100 seed weight, shoot dry weight can be translated into degree of tolerance. Therefore, these parameters can be used in wheat breeding for heat tolerance during grain filling period. The obtained results allow us to classify cultivars for heat stress tolerance. Pedigree information of Korean cultivars was shown that wheat line of either tolerant, moderate tolerant, or susceptible trait is succeeded to their descendent, which enable breeders to develop heat stress tolerant wheat by appropriate parental choice.