Cytogenetics and Reproductive Biology of <i>Bixa orellana</i> L. (Bixaceae)

Abstract

Summary Cytogenetic and reproductive assays were carried out on a population of annatto (Bixa orellana) of Southeastern Brazil. The reproductive data indicate that B. orellana is self-compatible but preferentially alogamous and entomophylous. No apomictic fruits were obtained from emasculated flowers. Fruits formed exclusively by self-pollination were smaller and had fewer seeds than those obtained by open pollination, highlighting the importance of pollination for annatto seed production. The meiotic process was analyzed and some abnormalities observed resulted in only some sterile pollen (1.9%) with no significant reduction of fertility. The cytogenetic studies showed the haploid chromosome number n=7 and the diploid number 2n=14, with a remarkable bimodal karyotype. FISH with 45S rDNA and 5S rDNA probes showed that these loci do not occur in synteny. Both probes hybridized in the proximal regions of the short arm of pair 1 (45S) and pairs 4 and 6 (5S). One pair of 5S rDNA sites presented larger signals in FISH than the other pair. These karyological features suggest that fusion of chromosomes and amplification of DNA segments played an important role in karyotype evolution of B. orellana.

Functional polymorphism in lycopene beta-cyclase gene as a molecular marker to predict bixin production in Bixa orellana L. (achiote)

“…These plants were originally collected from Yaxcaba, Cooperativa and Chicxulub Pueblo (the achiote plantation of the 'La Extra' Company), from the cultivation region of Yucatan State located at latitude 20°13 0 to 20°29 0 and longitude 88°55 0 to 89°54 0 . Each of these B. orellana plants could result from selfing or from crossing (Valdez-Ojeda et al 2010;Lombello and Pinto-Maglio 2014). They were genetically and morphologically characterized.…”

FISH with Padlock Probes Can Efficiently Reveal the Genomic Position of Low or Single-Copy DNA Sequences

“…Fluorescence in situ hybridization (FISH) can analyze the genomic position and distribution of DNA sequences in nuclei and on chromosomes (Ebadi-Almas et al 2012, Shirakawa et al 2012, Ikeda et al 2013, Kuroki et al 2013, Ruan et al 2013, Yokomi et al 2013, Suto et al 2013, Lombello et al 2014, Abozeid et al 2015, Kantek et al 2015, Matsunaga 2016, Monkheang et al 2016, Shibata et al 2016, Tantivit et al 2016, Jantarat et al 2017, Taguchi et al 2017. Labeling of DNA probes for FISH has been generally performed through enzymatic incorporation of labeled dNTPs by PCR or nick translation (Shibata and Hizume 2015).…”

FISH Is in the Limelight Again As More Than a Cytogenetical Technique for Metaphase Chromosomes

“…Chromosome banding techniques contribute not only to karyotyping but also to the identification of specific chromosomes (Afroz et al 2013, Alam et al 2013a, 2013b, Lombello and Pinto-Maglio 2014, Mahbub et al 2014, Manzum et al 2014, Tungkajiwangkoon et al 2015. Some chromosome banding techniques, including C-banding and G-banding, are strongly dependent on heterochromatin distribution in mitotic chromosomes (Sumner 2003, Bansal andKaur 2015).…”