GENIC ANALYSIS FOR ACID PHOSPHATASE ISOZYMES IN ORYZA PERENNIS AND O. SATIVA

It was concluded from genetic experiments that various acid phosphatase zymograms observed among the rice strains belonging to Oryza perennis Moench (wild) and O. sativa L. (cultivated) were controlled by alleles at three loci, Acp1, Acp2, and Acp3. At Acp1 seven codominant alleles were found each producing a group of three major (A, M, and C) and three minor (a, m, and c) bands on starch gel. The alleles determined mobility of the band group. Statistical analysis of the data taken from densitometric tracings of zymograms indicated that hybrids between strains with different mobilities would produce three major and three minor hybrid bands each occurring between two corresponding parental bands. In addition, a null form lacking all these bands was found that had a recessive allele, Acp1Nu1. The Acp1 locus was independent of Px1 (specifying peroxidase OC, 2A, and 4A bands), but was linked withPx2 (specifying peroxidase 4C band). The Acp2 locus carried two codominant alleles specifying bands Fa and Sa, respectively, and a recessive silent allele, Acp2Nu1. This locus was closely linked with Acp1, yet it was distinguished from the latter as different allelic combinations were observed among parental strains. At Acp3 alleles specifying bands B and b were found which were peculiar to O. perennis subsp. barthii; other perennis and sativa strains appeared to have their recessive silent alleles.

EXPERIMENTAL STUDIES ON THE ORIGIN OF CULTIVATED RICE

ABSTRACT 1) Contributions to the origin of cultivated rice made by the author and his colleagues were briefly reviewed under several headlines.—2) Two parallel series of evolution of cultivated species, the Asian form of Oryza perennis to O. sativa and O. breviligulata to O. glaberrima, were pointed out compared.—3) In both the two series, a continuous array of intergrades between wild and cultivated species is found in a particular region. The pattern of character variations among those intermediate plants was considered as indicating the evolutionary path, and the monophyletic origin of the Indica and Japonica types of O. sativa was discussed.—4) The conditions of establishment of a weedy form of O. perennis found in India were discussed. It was noticed that cultivation by man in itself works as a selective agent for cultivated types.