All three loci map to the long arm of chromosome
2 (for v*-424, see Chang, MGNL 56:44, 1982). Allelism tests between v*-424
and w3 or v4 were negative. I employed growth conditions which permitted
expression of all three phenotypes and confirmed the parental genotypes
for each pair tested. An F2 progeny of the cross: V*-424 v*-424 W3 W3 x
V*-424 V*-424 W3 w3 segregated green, albino (w) and virescent (v) seedlings:
Total | Green | v | w | |
Number of seedlings | 91 | 39 | 38 | 4 |
Germination was 100 percent. I did not observe any vivipary as is sometimes found for w3. The combined number of v and w individuals is somewhat high, but consistent with the segregation of two independent, recessive loci, if the v-class includes v*-424 v*-424 w3 w3. I will be testing this possibility by backcrosses to material containing only v*-424 or w3. Similar analysis of linkage between v*-424 and v4 is in progress. These two virescent loci can be distinguished by phenotype: v4 requires cold temperatures for expression while v*-424 is expressed at all temperatures tested (up to 95 F).
Mary Polacco
Return to the MNL 60 On-Line Index
Return to the Maize Newsletter Index
Return to the MaizeGDB Homepage