II.3 Identification of traits in barley accumulating carotenoid precursors.
W. D. Bell, Department of Botany, University of Florida, Gainesville, Florida 32601, U.S.A.
A white 3x5" card proved to be a useful tool for the rapid identification of a new barley trait comparable to white-3 in maize (Anderson and Robertson. Plant Physiol. 35:531-34. 1960.). A segregant grown from EMS-treated barley appeared paper-white against the card in contrast to the more common albina traits where traces of carotenoids in the latter could readily be seen against the colorless background. A further clue was found by observing this trait just below the substrate level where a bluish-green band identified as convertible protochlorophyllide could also be detected against the paper. Spectral analysis of 80% acetone extracts transferred to petroleum ether and saponified indicated the major pigment to be zeta carotene with a trace of phytofluene. Other traits, not necessarily white, which displayed the bluish-green band were tentatively identified as containing phytoene, phytofluene, prolycopene or delta carotene as the major carotenoid or precursor; all displayed when extracted the characteristic greenish fluorescence of phytoene under ultraviolet light except that which appeared to contain only phytoene. Carotenols were not found in any of the above. Relative frequency of such traits with the bluish-green band was about one per hundred observed albinas.