Research Article

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Aneuploidy; Apomixis; interspecific hybrid; Wild species

An interspecific hybrid between cassava and Manihot glaziovii acquired an apomixis gene from the parent M. glaziovii. This hybrid was exposed to open pollination during three subsequent generations. Seven sibs and the maternal progenitor of the fourth generation were genotyped using six microsatellite loci previously developed for cassava. All sibs were identical with ... more

N.M.A. Nassar; P.T.C. Gomes; A.M. Chaib; N.N. Bomfim; R.C.D. Batista; R.G. Collevatti
Apical meristems; Apomixis; Epigenetic; Pollen viability; Root productivity

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 ... more

D.Y. Hashimoto-Freitas; N.M.A. Nassar
Apomixis; Apospory; Heterosis; Interspecific hybridization; Triploid

Apomixis means seed formation without fertilization. In cassava (Manihot esculenta) it is an alternative to reproduction by cuttings, which normally transmits pathogens and leads to an accumulation of viral and bacterial diseases. Apomixis also assures preservation of heterosis and avoids genetic segregation. It occurs in wild relatives of cassava and has been transferred ... more

N.M.A. Nassar
Amino acids; Apomixis; Drought; Protein

Wild cassava relatives are perennials and vary in growth pattern from nearly acaulescent subshrubs to small trees. They have been used as a source of useful characters such as high protein content, apomixis, resistance to mealybug and mosaic disease, and tolerance to drought. Indigenous clones are a potential source of β-carotene and lycopene. Apomixis genes have been transferred to the crop ... more

N.M.A. Nassar
Apomixis; Microsatellite; Open pollination; Protogeny; Second generation progeny

Cassava is the main staple for more than 800 million people in the tropics. It is propagated vegetatively by stem cuttings, which maintains superior genotypes but favors disease accumulation and spread. In this report, we present the results of the screening of the progeny and the second generation of the clone UnB 307 for apomixes using microsatellites. A total of 29 plants were ... more

N.M.A. Nassar; D.C. Kalkmann; R. Collevatti
Apomixis; Interspecific crosses; Polyploidy

A new species was synthesized artificially by chromosome doubling in a hybrid. The ensuing polyploid type exhibits an apomictic nature and maintains its morphological characteristics in the progeny. It showed a frequency of multiembryonic sacs of 29% in the ovules examined, whereas sacs were absent in the diploid type.

*In honor of deceased Professor Vieira who dedicated a part ... more

N.M.A. Nassar
Apomixis; Molecular marker; Satellite technique

Apomixis genes have been successfully transferred to cassava (Manihot esculenta) by hybridizing it with the wild species, M. glaziovii. The interspecific hybrid of cassava and M. glaziovii was exposed to open pollination during three subsequent generations. Seven sibs and the maternal progenitor of the fourth generation were genotyped using five ... more

N.M.A. Nassar; R.G. Collevatti
Anatomy; Cassava hybridization; Embryology; Genetics

A molecular, anatomical and cytogenetic study of an interspecific hybrid between Manihot esculenta (cassava) and the wild species M. oligantha was carried out. Cytogenetics revealed relatively complete chromosome pairing and high viability of the pollen grains. Ovule structure examined by the clearing method showed polyembryony in 2.7% of the ovules. Doubling of the ... more

N.M.A. Nassar; D.Y. Hashimoto; D.G. Ribeiro