1)National Institute of Genetics, Mishima, 411 Japan
2)Institute for Agricultural and Biological Sciences, Okayama University, Kurashiki, 710 Japan
The Indica and Japonica rice cultivars can be distinguished by multivariate
analysis of isozyme variations as reported by Second (1982) and Glaszmann et
al. (1984). Frequency distribution of multilocus genotypes for six diagnostic
isozyme loci found in the Indica and Japonica varietal groups, classified on
the basis of character-association pattern, is given in the bottom lines of
Table 1.
Table 1. Between-and within-populational variations in isozyme genotypes found in Nepalese land-races collected at different altitudes.
============================================================================== Locus Isozyme genotype ---------------------------------------- Cat-1 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 Acp-1 +9 +9 -4 -4 -4 +9 +9 +9 +9 -4 -4 -4 -4 -4 -4 -4 -4 -4 Pgi-1 2 2 2 2 1 2 2 2 1 2 2 2 2 2 1 1 1 1 Pox-2 0 0 0 0 4C 0 0 4C 0 0 0 0 4C 4C 0 0 4C 4C Pgi-2 1 4 1 4 1 1 2 2 1 1 2 4 1 2 1 2 1 2 Est-2 {0 1 {0 1 0 {0 2 2 1 1 {1 0 2 1 {0 {0 {0 {0 1 1 1 2 2 1 1 1 2 2 2 Nepalese land races Popu- No.of Alt. lation plants (m) -------------------- ---------------------------------------------------- KK-3 13 1970 11 2 JENA46-48 3 1780 3 JENA51-52 2 1770 2 KT-8 6 1770 6 JENA54-55 2 1750 2 KT-7A 14 1750 8 6 KT-7B 21 1750 8 11 1 1 PK-2 4 1500 1 3 KK-1 32 1500 2 30 JENA39-42* 4 1460 3 1 JENA30-38* 8 1460 1 7 JENA24-28* 4 1457 4 JENA20-23 4 1440 2 1 1 JENA15-17 3 1440 1 1 1 KK-4A 6 760 1 4 1 JENA60 1 350 1 ----------------------------------------------------------------------------- Asian varieties Japonica type 50 Indica type 1 1 1 6 1 2 4 3 9 20 ==============================================================================For Est-2, different alleles are pooled to save space.
*Upland field.
To see how genetic variation among rice cultivars is related to changing
altitude, 16 populations of land races collected at different altitudes in
Nepal were assayed for the above six isozymes by starch-gel system. The loci
examined were Cat-1, Pgi-1, Pgi-2, Acp-1, Pox-2 and Est-2. The variation
pattern observed in these materials showed a cline corresponding to the
altitude of collection sites (Table 1). The samples collected at the sites
higher than 1750 m, consistently showed a particular genotype which was
specific to the Japonica type. Those collected at the lower altitudes were
heterogeneous among and within populations and exhibited various genotypes
which were found in the Indica type. The distribution pattern of rice
cultivars in the hilly areas might be conditioned by dissemination and
isolation under diverse natural and ethnological conditions. yet, the present
result suggests that, in Nepal, the Indica and Japonica types are distributed
in the low and high altitudes, respectively.
References
Glaszmann, J.C., H. Benoit and M. Arnaud, 1984. Classification de riz cultivars (Oryza sativa L.): Utilisation de l variabilite isozymatique. Agr. Trop. 39:51-66.
Second, G., 1982. Origin of the genic diversity of cultivated rice (Oryza spp.): Study of the plymorphism scored at 40 isozyme loci. Jpn. J. Genet. 57:25-57.