L. Cheesmanii.

Rick, C. M.

After a number of years of fruitless correspondence with residents and explorers of the Galapagos, we have succeeded in securing viable seeds of L. Cheesmanii. They were very kindly transmitted by Alf Kastdalen a Norwegian settler on Santa Cruz. The seeds had been collected by a fisherman on Isla S. Bartolome, a small islet close to the east coast of James Id.

The seeds show a dormancy similar to but not quite so extreme as that of the previously described L. pimpinellifolium from the Galapagos (TGC 4:16). Numerous plants have been grown at Davis both in the field and greenhouse, and, in all respects they conform closely to the written descriptions and herbarium specimens of L. Cheesmanii f. minor. All parts are diminutive, internodes remain short (1-2 cm under all tested conditions: leaves are highly dissected; herbage is densely covered with long hairs; calyx segments become large and completely envelope the enlarging fruit. Of particular interest is the orange color of the mature fruits -- a condition not previously indicated in either collectors' notes or taxonomic descriptions. Chromatographic analyses made by Dr. G. Mackinney reveal that Beta-carotene comprises practically all of the carotenoids of the ripe fruits.

Compatibility tests have been completed between this accession and critical tester lines of other species. As with the pimpinellifolium accession, it shows complete compatibility with L. esculentum and L. pimpinellifolium but does not hybridize with tested collections of any other species. The F1 with L. esculentum is fertile in all respects, shows normal chromosome pairing. No disruptions were observed in viability or fertility of relatively large F2 and B1 to L. esculentum. The genetic tests put this accession in the same situation as L. pimpinellifolium. It is especially significant to us that it vas first classified as L. esculentum var. minor by Hooker, and the present evidence strongly argues that it should be returned to that status.

The high Beta-carotene responsible for the orange fruit color is inherited in the B1 to L. esculentum in the fashion of a single dominant. It is very likely that the gene is B since both are very tightly linked with sp and show identical phenotypic effects.

Seed of this accession has been increased and is available for distribution.