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HYBRIDIZATION STUDIES IN PERENNIAL ZINNIAS
Author(s) -
Torres Andrew M.
Publication year - 1964
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1964.tb06672.x
Subject(s) - biology , chiasma , polyploid , hybrid , ploidy , subgenus , botany , chromosome , homologous chromosome , genetics , genus , gene
Results of hybridization studies among the 6 species of subgenus Diplothrix ( Zinnia‐ compositae) are reported. Also included are analyses of chiasmata frequency in the parental species and 2 diploid hybrids. Pairing relationships and chiasmata frequency of the chromosomes in the hybrids of the diploid species indicate their genomes are homologous. Analyses of F 2 's of Z. juni‐perifolia X acerosa (2 n ) show that production of pigment in ray flowers, C, from Z. juniperifolia segregates as a simple dominant over colorless, cc, from Z. acerosa. Morphological studies of the hybrids produced to date indicate that the origin of the polyploid taxa has been more circuitous than simple hybridization followed by chromosome doubling. The genomic constitution of Z. juniperifolia is designated A 1 A 1 , that of Z. acerosa A 2 A 2 , and that of Z. oligantha A 3 A 3 . Morphological data and chromosomal pairing in the polyploid hybrids suggest that the tetraploid species should be tentatively assigned genomic formulae as follows: A 1 A 1 A 2 A 2 or A 1 A 1 A 3 A 3 for both Z. citrea, and Z. grandiflora, and A 2 A 2 A 3 A 3 for 4 n Z. acerosa.