Table 1. Seed fertility of F\1\ plants (in %)
Department of Agronomy, Seoul National University, Suweon, 170 Korea
The weed rice locally called "Sharei" occurs in direct-seeded upland rice
fields near the mouth of the Hangang River (at Samsam Myun, Ganghwa Gun,
37degrees 44'N, 126degrees 19'E; Fig. 1). Due to their weedy characteristics
such as pronounced seed dormancy (seeds surviving in the field more than one
year), high rate of grain shattering by wind, and drought tolerance, the plants
have persisted as a weed of rice field since times immemorial (Ree et al. 1983;
Oka 1988, p. 112).
They are heterogeneous in plant type, panicle and grain shape, and seed fertility, and vary between the Japonica and Indica types. The seed coat color also varies from dark purple, red and brown to white or colorless.
A total of 440 plant samples were collected from the area. Some of them were grown in greenhouse, and crosses were made with a Japonica strain S222, and Indica strain wx834, and a so-called Javanica strain Kn-1B-361 to examine their F\1\ sterility (Table 1). The results showed evidently that the "Sharel" plants had closer cross-affinity to the Korean Japonica strain than to other strains. The heterogeneity of the population and the F\1\ sterility relationships may offer some information as to the evolution of Korean rice cultivars.
Fig. 1. A weedy rice "Sharei" in an upland rice field.
Table 1. Seed fertility of F\1\ plants (in %)
References
Oka, H.I., 1988. Origin of Cultivated Rice. Elsevier/Japan Sci. Soc. Press, 154 pp.
Ree, D.W., Y.K. Hong, J.C. Kim and Y.H. Kim, 1983. Ecological characteristics of Red rice and factors affecting its competition with rice. Korean J. Weed Sci. 3(2): 143-150.