title: Cytogenetic and anatomic behavior of cytochimeras and total polyploids in cassava.
abstract: Cassava periclinal cytochimeras, cultivars, and interspecific hybrid and polyploid types were studied in relation to embryonic, cytogenetic, and anatomical behavior. Their apical shoots, pollen grains, male and female buds, roots, stomata, and flowering period were analyzed. Chimeras exhibited increased size of L1 and L2 cells. Polyploidy led to enlargement of stomata in chimeras whereas L2 gave tetraploid chromosome configurations, tetrad irregularity, decrease of pollen viability, and increase in frequency of polyembryo sacs. The chimeric composition of tetraploids L1 and L2 and diploid L3 expressed a notable epigenetic effect seen in a marked enlargement of edible roots compared to total diploid. One of the chimeric types was accompanied by complete flowering inhibition. Pollen viability and diameter appeared to be reliable markers to determine ploidy levels.
authors.affiliation: Programa de Pós-Graduação em Botânica, Universidade de Brasília, Brasília, DF, Brasil.
authors.forename: D Y
authors.initials: DY
authors.lastname: Hashimoto-Freitas
authors.forename: N M A
authors.initials: NM
authors.lastname: Nassar
mesh_terms: D002678:Chimera; D032461:Chromosomes, Plant; D020732:Cytogenetic Analysis; D004171:Diploidy; D002365:Manihot / Q000033:anatomy & histology* / Q000196:embryology / Q000235:genetics*; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000033:anatomy & histology; D054046:Plant Stomata / Q000235:genetics; D011058:Pollen / Q000235:genetics; D011123:Polyploidy; D057885:Triploidy