Pollens of the octoploid
plants were collected by shaking flowers and pollens were placed in the small container.
HT22, HT24, HT44, and HT47 are primary hexaploid tritordeums (2n = 6x = 42) while HT18 is an octoploid
one (2n = 8x = 56).
The cytology of tetraploid "Bromus inermis" and [C.sub.o] colchicine-induced octoploid
Although partial sterility is observed, chromosome pairing and vigorous [F.sub.1] hybrids within and between the hexaploid South American and octoploid
North American groups reflect close relationships (Stebbins and Tobgy, 1944; Stebbins, 1947, 1981; Hall, 1955; Naranjo, 1992).
Love), the sole member of the genus (Love, 1980), is octoploid
(Gillet and Senn, 1960), although aneuploids are frequent in this species because it may propagate by rhizomes (Dewey, 1975).
Schulz-Schaeffer and Hailer (1987) predicted that the chromosome number of the original amphiploid (2n = 70) would stabilize at the octoploid
level (2n = 56) and hypothesized that, because of the Triticum cytoplasm, the 14 lost chromosomes would belong to the Thinopyrum parent.
Meiotic studies on pollen plants of F1 between octoploid
Triticum-Agropyron and common wheat.
aestivum L., with rye, Secale cereale L., followed by doubling of the chromosome number to produce fertile hexaploid and octoploid
With the exception of Paspalum almum (2n=12, 24), all the species studied here have chromosome numbers which are multiples of 10, varying from diploids to octoploids
. The results show a surprisingly high frequency of diploid species (44%), as well as diploid accessions (35.7%), when compared to the predominant tetraploids (43.6 %) and the remaining ploidy levels (20.7% altogether).
Through descending dysploidy, a second basic number x = 6 was derived, relative to which the somatic chromosome numbers 24 and 48 are tetraploids and octoploids
Intergeneric crosses have also been used for ploidy reductions, for example to reduce octoploids
to tetrahaploids in strawberry (Janick & Hughes, 1974).
Cytogenetic analyses of autopolyploids: models and methods for triploids to octoploids