Research Article

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Apomixis; Callose; Embryology; Flow cytometry screen seed; Sexual reproduction

Apomixis is a particular mode of reproduction that allows progeny formation without meiosis and fertilization. Eulaliopsis binata, a tetraploid apomictic species, is widely used for making paper, rope and mats. There is great potential for fixation of heterosis in E. binata due to autonomous endosperm formation in this species. Although most of its embryo sac originates ... more

L. Liu; J.J. Li; Y.D. Ouyang; J.L. Yao
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
Brachiaria; environment; interspecific hybrid; Microsporogenesis

Microsporogenesis in an interspecific Brachiaria hybrid, grown in the field under natural environmental conditions in Brazilian savannas, was analyzed in three distinct years of collection. Several types of meiotic abnormalities were recorded during those three years, but varied in type and frequency depending on the year. The average temperature and rainfall 15 days before collection ... more

V.A. Fuzinatto; M.S. Pagliarini; C.B. Valle
Aechmea; Genetic divergence; interspecific hybrid; SRAP

Conventional hybridization and selection techniques have aided the development of new ornamental crop cultivars. However, little information is available on the genetic divergence of bromeliad hybrids. In the present study, we investigated the genetic variability in interspecific hybrids of Aechmea gomosepala and A. recurvata var. recurvata using inflorescence ... more

F. Zhang; Y.Y. Ge; W.Y. Wang; X.L. Shen; X.Y. Yu
Genetic divergence; interspecific hybrid; Joint analysis; Morphoagronomic characterization; Ward-modified location model (MLM) method

Morphological characterization is the most accessible and used method to quantify the genetic diversity of the available germplasm. The multivariate statistical method is highly important for this purpose. This study aimed to characterize parents and hybrids of Passiflora according to morphoagronomic descriptors and estimate the genetic divergence between them based on the joint ... more

E.A. Santos; A.P. Viana; J.C.O. Freitas; M.M. Souza; C.L. Paiva; D.L. Rodrigues; R.F. Tavares