11. A new allele of Amp-4 in a traditional rice cultivar

International Rice Research Institute, P. O. Box 933, Manila, Philippines

Isozymes are important biochemical markers for genetic and breeding research. Out of 48 isozyme loci identified in rice, 33 have been located to 10 of the 12 chromosomes (Khush and Kinoshita 1991). Glaszmann (1987) classified Asian rice germplasm into different varietal groups based on isozyme pattern. Since then, the technique is commonly used for the classification of rice germplasm. We have analyzed isozyme patterns of 1256 traditional rice germplasm from Philippines.

Amp-4 located on chromosome 8, codes for an enzyme having substrate specificity with Arg-N Am. In O. sativa only three alleles of the Amp-4 locus have been reported: Amp-4¹, Amp-4² , and Amp-4³ . Our analysis showed that cultivar with allele 1 are very common (98.32% accessions), allele 2 is rare (1.58% accessions). Amp-4 , another rare allele was not observed in the Philippines nce germplasm. Glaszmann et al. (1988) reported allele 3 in a Myanmar variety, Yelaik Meedon (Table 1). A new allele was observed in a traditional indica rice variety from Philippines, Kayadin (accession no. 8149). This allele is designated Amp-44. It forms slow moving band in comparison to previously known alleles (Fig. 1).

Table 1.  Rice cultivars carrying variant alleles at Amp-4
_______________________________________________________________________________
Allele  Cultivar        Acc. No.  Variety  Origin
                                  Group
_______________________________________________________________________________
   1    IR36             -        1        IRRI

   2    Ma hae          23754     6        Thailand

   3    Yelaik Meedon   33889     1        Myanmar

   4*   Kayadin         8149      1        Philippines
_______________________________________________________________________________
*New allele.

References

Glaszmann, J. C., 1987. Isozymes and classification of Asian rice varieties. Theor. Appl. Genet. 74: 21-30.

Glaszmann, J. C., B. G. delos Reyes and G. S. Khush, 1988. Electrophoretic variations of isozymes in plumules of rice (Oryza sativa L.) - a key to identification of 76 alleles at 24 loci. Research Paper Series No. 134, International Rice Research Institute, Manila, Philippines.

Khush, G. S. and T. Kinoshita, 1991. Rice karyotype, marker genes and linkage groups. Pages 83-108 In Rice Biotechnology. G. S. Khush and G. H. Toenniessen, eds. CAB International, Wallingford, U. K.