Polyploidy was induced in Melia volkensii (Mukau), a valuable native tree from the semi-arid regions of East Africa. Cotyledons diploid M. (2n = 2x 28) were treated with oryzalin for 0 (control), 1, 2, or 3 h without pretreatment 1.1 µM thidiazuron. 10 mg·L−1 three hours yielded 40% tetraploids. Pretreatment cotyledons thidiazuron 18 days followed by treatment increased tetraploid plant product...

Two major aspects have made the genetic and genomic study of polyploids extremely difficult. First, increased allelic or nonallelic combinations due to multiple alleles result in complex gene actions and interactions for quantitative trait loci (QTL) in polyploids. Second, meiotic configurations in polyploids undergo a complex biological process including either bivalent or multivalent formatio...

The forage palm is widely cultivated in semiarid regions. It has a basic chromosome number of x = 11 and polyploids are the main variation. propagated via vegetative reproduction, sexual propagation rarely used. objective was to associate physiological quality seeds different cultivars with level ploidy genera Opuntia Nopalea. used were: diploids (2n 22) ‘F8’, ‘F21’, ‘IPA Sertânia’; tetraploids...

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 gav...

Polyploidization has crucial impacts on the evolution of different eukaryotic lineages including fungi, plants and animals. Recent genome data suggest that, for many polyploidization events, all duplicated chromosomes are maintained and genome reorganizations occur much later during evolution. However, newly-formed polyploid genomes are intrinsically unstable and often quickly degenerate into a...

The aim of this work was to evaluate the carotenoid content and genetic variability of banana accessions from the Musa germplasm collection held at Embrapa Cassava and Tropical Fruits, Brazil. Forty-two samples were analyzed, including 21 diploids, 19 triploids and two tetraploids. The carotenoid content was analyzed spectrophotometrically and genetic variability was estimated using 653 DArT ma...

Most human somatic cells do not divide indefinitely but enter a terminal growth arrest termed replicative senescence. Replicatively senescent cells are generally believed to arrest in G1 or G0 stage of the cell cycle. While doing cell cycle analysis on three different lines of normal human fibroblasts we observed that 36-60% of the replicatively senescent cells had 4N DNA content. Only up to 5%...