New Observations on the Expression of the Gene cl for Circumlineated Patterns of Partly Colored Seed Coats - a Gene Carried by Recurrent Parent Line 5-593

摘要

R. Prakken (1972) discovered the gene cl (for circumlineatus) in a cross between 'White J'(T z cl Rk) X 'Soldaat K' (t z Cl rk~d), which expressed circumlineated patterns of partly colored seed coats with either virgarcus or more restricted patterns.In the genetic background P t z C J g B v, he described the effects of cl as "the coloured part (or the separate units of it, even the finest colour dot) is sharply demarcated from the white part of the seedcoat by a narrow line (of a clear orange in Rk/- seeds and of a much darker colour in rk~d/r~d ones), giving the impression of some sort of precipitation on the border between the coloured and uncoloured parts." There is no mention of a groove in the seed surface at the border between the colored andnot colored (white) zones, as I have discovered in other materials carrying cl. For example, when I converted the genetic stock, t z virgarcus BC_3 5-593, to seed coat colors other than black, all progenies segregating for t and partly colored patternswere true breeding for cl. The three color stocks used were mineral brown (v BC_3 5-593), yellow brown (b v BC_3 5-593), and shamois (g b v BC_3 5-593). In the F_2 progenies from each backcross of the three color stocks to the black seeded virgarcus stock, the black virgarcus segregants never showed either the groove or the precipitation line, but all other non-black virgarcus segregants were true breeding for both the groove and the precipitation line. Other more expansive partly colored patterns werealso true breeding for cl expression. From those results, I infer that 5-593 carries genotype cl. My next challenge was to convert 5-593 to the dominant allele, Cl, to create a new genetic stock.