Production and Evaluation of Agronomic Characters of IntrogressionLines from the Cross of Hwaseongbyeo x O. minuta in Rice

Wild rices are an important source of useful genes for resistance to diseases, insect pests, tolerance for abiotic stresses and yield increase. O. minuta (BBCC), a tetraploid wild rice having 48 chromosomes, was used for the cross with japonica rices. Fertile introgression lines of $BC_{3}$$F_{2}$ to $BC_{5}$$F_{5}$ generation were successfully obtained from an interspecific cross between a japonica cultivar, Hwaseongbyeo and O. minuta (ACC. 101144). The agronomic performance of $F_{2}$($BC_{3}$$F_{2}$, $BC_{5}$$F_{2}$) and $F_{3}$($BC_{3}$$F_{3}$, $BC_{4}$ $F_{3}$, $BC_{5}$$F_{3}$) lines were evaluated for yield and yield components and reactions to disease and insect pests. As the backcross and selfed generation advanced, the agronomic traits tended to approach to the recurrent parent, Hwaseongbyeo, However, considerable agronomic variations were found among the population and agronomically varied lines were produced for all the traits measured. Observational yield test was conducted with 42 selected lines in $BC_{5}$$F_{5}$ generation. The overall phenotype of OYT lines resembled to the recurrent parent, Hwaseongbyeo without any wild traits such as grain shattering, long awn and leaf smoothness. The mean agronomic performance showed the improved traits, reduced height, increased spikelet number per panicle, and 1000-grain weight. Especially, the top five high-yielding lines showed 18 to 27% of yield increase, suggesting that positive yield-related alleles from wild species were combined to the recurrent parent