Abstract
Although two rice varieties, Pi No. 4 and Pi No. 1, had been bred by repeatedly crossing some Japanese varieties with the Philippine variety, Tadukan, they appear to have different reactions to some blast fungus strains. Gene analyses of Pi No. 4 indicated that resistance of this variety is different from one controlled by the gene Pi-ta of Pi No. 1. A gene or a group of closely linked genes controlling this resistance was symbolized as Pi-ta2 which is independent or remote from the loci, Pi-a, Pi-k. Pi-i and Pi-z, and on a locus allelic to or closely linked with the gene Pi-ta in the variety Pi No. 1.
