15. A. "Fish-hook" mutation in rice

A striking recurved and sharply pointed modification of the lemma appeared uniformly in an F\5\ dwarf line. "Hooked", "parrot beaked" and "claw shaped" lemmas have been reported, but this is perhaps more extreme. The lemma tips will hook into clothing and support an entire panicle. This mutation could function for seed dispersal in wild rice. It would be a useful genetic marker if it segregates in a clear-cut manner.

The florets did not open in response to hot water treatment, probably becasuse the lemma and palea clamp together tightly. However, the seed set was fairly good. A cross with an IR 8 derived dwarf was obtained. The F\1\ was a somewhat sterile non-dwarf with very slender spikelets which were not hooked. The F\2\ was classified as: 47 hooked (some or all spikelets), 128 with the lemma tilted toward the palea but not recurved, and 10 normal apiculus.

It appears that "hooked" is controlled by a recessive gene; it was not expressed in the F\1\ and constituted 1/4 of the F\2\ population. However, this does not account for the intermediate "tilted" class. Duplicate dominant genes for "tilted" are suggested by the 15 : 1 ratio of "tilted" to normal". Assuming that "hooked" is epistatic to "tilted", a combined ratio of 45 "tilted" : 3 normal" : 16 "hooked" results. Agreement with expected is very close, but F\3\ progeny tests were not conducted.