A.C. sanchez and G.S. khush

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

We obtained a spontaneous mutant for white panicle character in rice. The mutant was isolated from rice cv. Padi Selaka-gogo planted in our hybridization nursery. The mutant plants exhibit white striped leaves at seedling stage. The white stripes are generally confined to the first three leaves. The plants produced white panicles at flowering. The rachis and the pedicel are also milky white in color.

We crossed this mutant with IR36 which has green panicles. The F₁ had green panicle and the F₂ population segregated in aratio of 3 normal : 1 white panicle, thus showing that the white panicle character is a monogenic recessive trait.

The mutant is similar to another white panicle mutant wp1 we reported earlier (Sanchez and Khush, 1994). The wpl mutant was obtained from Dr. R.N. Misra of the Central Rice Research Institute (CRRI), India. Unlike the new white panicle mutant, the rachis and pedicel of wp1 are green. We made the allele test between these two white panicle mutants and the F₁ had normal phenotype. The F₂ segregated in a ratio of 9 normal : 7 white panicle (Table 1 ). These results show that the new white panicle mutant is non-allelic and independent of wp1. We have designated this mutant as wp2.