16. A new allele of Enp-1 in rice germplasm of Vietnam

Luu-Ngoc TRINH¹, B.C. delos REYES², D.S. BRAR² and G.S. KHUSH²

1) Vietnam Agricultural Science Institute, Hanoi, Vietnam

2) International Rice Research Institute, Manila, Philippines

Table 1.  Rice cultivars carrying variant allele 3 for Enp-1
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Cultivar       Accession  Varietal  Distribution   Culture Type
                 number     group
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Canhan           32099      1      South Vietnam   early, plain area
Sai Hai duong    47551      1      North Vietnam   winter rice
Du Hai  duong    60726      1      North Vietnam   aromatic rice
Khau danh        73201      1      North Vietnam   mountainous rice
Doc Phung          201      1      South Vietnam   lowland rice, plain area
Lua Noi          10242      1      South Vietnam   lowland rice, plain area
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Fig. 1. Zymogram showing new variant allele 3 for Enp-1 in Vietnamese germplasm.

Isozymes are important biochemical markers in genetic and breeding research. Of the 48 isozyme loci identified in rice, 33 have been located to 10 of the 12 rice chromosomes (Khush and Kinoshita 1991). Glaszmann et al. (1988) identified 76 alleles at twenty four isozyme loci using starch gel electrophoresis. We analyzed isozyme pattern of 746 varieties of rice from Vietnam using starch gel electrophoresis. In O. sativa only two alleles (0 and 1) for the Enp-1 (Endopeptidese) locus are known (Glaszmann et al. 1988). Another allele designated as Enp-1² was identified in the wild species, O. nivara (Acc 104443) and Enp-1 was located on chromosome 6 through primary trisomic analysis (Brar et al. 1991). We identified a new alelle at this locus in O. sativa cultivars from Vietnam.

Among 746 cultivars analyzed, 6 were found with allele 0 (0.8%), 734 with allele 1 (98.4%) and 6 with a new allele (0.8%) designated as allele 3 (Table 1). The new allele exhibits intermediate mobility between allele 1 of O. sativa and allele 2 of O. nivara (Fig. 1). The six Vietnam cultivars with new allele (Enp-1³) are Indicas (Group 1) and are non-glutinous (Table 1). It is interesting to note that some of the cultivars with the new allele are from North and others from South Vietnam and are grown in different ecosystems ranging from lowland to mountainous areas.

References

Brar, D.S., B.G. delos Reyes, O. Panaud, A. Sanchez and G.S. Khush, 1991. Genetic mapping in rice using isozyme and RFLP markers. Rice Genetics II, p. 137-145. International Rice Research Institute, Manila, Philippines.

Glaszmann, J.C., B.G. delos Reyes and G.S. Khush, 1988. Electrophoretic variation of isozymes in plumules of rice (Oryza sativa L).-a key to the 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. In: Rice Biotechnology (G.S. Khush and G.H. Toenniessen, eds.). p.83-108. CAB International, Wallingford, U.K.