The Genus Collinsia XXIX
Preferential pairing in diploid, triploid, and tetraploid interspecific hybrids involving C. stricta×C. concolor and related species
1968 Volume 33 Issue 2 Pages 246-255
Details
1968 Volume 33 Issue 2 Pages 246-255
Thirty hybridizations involving species and unnamed collections belonging to the genus Collinsia, and the F2 progeny from C. stricta×C. concolor were attempted; 5 gave viable seed. The hybrid between C. concolor and C. parryi was an amphidiploid and those between C. concolor and C. stricta×C. concolor were triploids, an anomalous polyploid (3N+1 to 4N+2), and an amphidiploid; the other hybrids were diploid. Hybrids between C. stricta×C. concolor and C. stricta or C. heterophylla had bivalents and univalents, and hybrids between C. strictaa×C. concolor and C. multicolor had an interchange complex of 6 chromosomes; the amphidiploid for C. concolor×C. parryi exhibited not more than 2 quadrivalents, and the amphidiploid for C. concolor×(C. stricta×C. concolor) only bivalents and occasionally univalents. The diploid hybrids had a low chiasma frequency at metaphase I (1.0 1.4), and the polyploid hybrids had a high chiasma frequency (1.7-1.8). Diploid hybrids, except for those involving C. heterophylla, and the polyploid hybrids were fertile to some extent. The preferential pairing observed in the 2 amphidiploids was explained by assuming 2 types of cryptic structural hybridity.
