Author : Soledad, Blanquita S.

Summary : The segregation pattern of peroxidase isozymes was studied in two wild rice species, namely: Oryza nivara and O. rufipogon, and in hybrid populations in their crosses with cultivated rice O. sativa using polyacrylamide disc gel electrophoresis. Eight peroxidase bands were observed on the parents and two new bands, Px (subscript 1)Px (subscript 3) and Px (subscript 1)Px (subscript 4), from the F (subscript 1) and F (subscript 2) progenies. Peroxidases 1 (Px (subscript 1)) and 6(Px (subscript 6)) were found to be common in all species. A hybrid isozyme, Px (subscript 1)Px (subscript 4), was observed in the hybrids of O. nivara (Acc. no. 101524) and O. RUFIPOGON (Acc. no. 101448) with IR 42. Based on F (subscript 2) segregation, Px (subscript 1)Px (subscript 4) appeared to be a product of the interaction between genes Px (subscript 1) of O. SATIVA (IR 42) and Px (subscript 4) of O. NIVARA (Acc. no. 101524) and O. RUFIPOGON (Acc. no. 101448). The isozyme Px (subscript 1)Px (subscript 3) must have resulted from an interaction between gene Px (subscript 1) of IR 42 and Px (subscript 3) of O. RUFIPOGON (Acc. no. 100960). Isozymes coded by genes Px (subscript 1), Px (subscript 3), and Px (subscript 4) were presumed to be dimetric. Allelism and codominance of these genes could produce a hybrid isozyme in the heterozygotes, a hypothesis supported by the F (subscript 2) data which showed a good fit to the expected 1 (Px (subscript 1)): 2 (Px (subscript 1)-Px (subscript 1) Px (subscript 4)- Px (subscript 4):1 (Px (subscript 4)) or 1 (Px (subscript 1)): 2 (Px (subscript 1)-Px (subscript 1)Px (subscript 3)-Px (subscript 3)): 1 (Px (subscript 3)) segregation ratio.