Chromosome behaviour in autotetraploid cereals and grasses

A pairing restriction at pachytene upon multivalent formation in autotetraploids

“…valents, particularly of trivalents, at meiosis in the autotetraploids, a paucity widely reported among other species (see Callan, 1949;Morrison and Rajhathy, 1960;John and Lewis, 1962). John and Henderson's model assumes, however, a random association within each homologous set at pachytene.…”

Colchicine-Induced Autotetraploidy in Clitoria ternatea L.

“…According to Kostaff (1940), large size of the chromosomes have direct bearing on multivalent frequency. However, Morrison and Rajhathy (1960a) and Srivastav and Raina (1982) suggested that multivalent frequency in autotetraploids was largely dependent on short size of chromosomes. Present studies indicate that apart from chromosome size, other factors such as chiasma frequency which is under genetic control, heterozygous nature of plants, environmental conditions etc., might also be responsible for multivalent formation (Riley and Chapman 1958).…”

“…In C. ternatea there is lack of association of pollen fertility and seed set suggesting possibility of other factors in addition to meiotic abnormalities and pollen fertility being involved in seed set. According to Morrison and Rajhathy (1960b), in autotetraploids environmental, physiological and genetical factors are also responsible for poor seedset.…”

Genotypic control of chromosome behaviour in rye X. Chromosome pairing and fertility in autotetraploids

“…What evidence there is is contradictory. For example, in the work of Morrison and Rajhathy (1960) on autotetraploids in a number of species there is no evidence for heritable variation in the chromosome pairing pattern and no indication, either, that variation in the pairing pattern affects fertility. McCollum (1958), on the other hand reports that high fertility in autotetraploid Dactylis is achieved in association with high quadrivalent frequency.…”