24. A new null allele at Amp4 locus in a traditional rice cultivar

S.X. tang, G.S. khush and D.S. brar

International Rice Research Institute, P. 0. Box 933, 1099 Manila, Philippines

 Isozymes are important biochemical markers for genetic and breeding research. To classify the traditional rice germplasm from Yunnan, China, we analyzed 527 cultivars through starch gel electrophoresis for 16 isozyme loci following procedures of Glaszmann et al. ( 1988). Null alleles that are not transcribed or that code for defective polypeptides lacking enzymatic activity, were identified for 5 isozyme loci, namely Pgil, Est1, Est2, Est5 and Est9 in Yunnan germplasm.

So far, 4 alleles for Amp4 have been identified in rice (Glaszmann et al. 1988, Malik and Khush 1994). We report a new null allele for Amp4 in a japonica cultivar, Shuizhagu

Fig. 1. Zymogram of Amp4-1 and Amp4-null.

76 Rice Genetics Newsletter Vol. 14

and designate it as Amp4-null (Fig. 1). The new allele was found at a very low frequency of 0.2% in Yunnan rice germplasm.

References

Glaszmann, J.C. B.C. (Jelos Reyes and G.S. Khush. 1988. Electrophoretic variation of isozymes in plumules of rice (0. sativa L.) - a key to the identification of 76 alleles at 24 loci. IRRI Res. Paper Series No. 134, International Rice Research Institute, Manila, Philippines, pp. 15. Malik, S.S. and G.S. Khush, 1994. A new allele of Amp4 in a traditional rice cultivar. RGN II:

88-89.