Describing the genetic diversity in the gene pool of crops will provide breeders with novel resources for varietal improvement. Nested Association Mapping (NAM) populations are uniquely suited for characterizing parental diversity through the shuffling and fixation of parental haplotypes. Here, we describe a set of 1879 rice NAM lines created through the selfing and single-seed descent of F1 hybrids derived from elite IR64 indica crossed with 10 diverse tropical japonica lines. Genotyping data indicated tropical japonica alleles were captured at every queried locus despite the presence of segregation distortion factors. Several distortion loci were mapped, both shared and unique, among the 10 populations. Using two-point and multi-point genetic map calculations, our datasets achieved the ∼1500 cM expected map size in rice. Finally, we highlighted the utility of the NAM lines for QTL mapping, including joint analysis across the 10 populations, by confirming known QTL locations for the trait days to heading.

Rice hoja blanca (white leaf) disease can cause severe yield losses in rice in the Americas. The disease is caused by the rice hoja blanca virus (RHBV), which is transmitted by the planthopper vector Tagosodes orizicolus. Because classical breeding schemes for this disease rely on expensive, time-consuming screenings, there is a need for alternatives such as marker-aided selection. The varieties Fedearroz 2000 and Fedearroz 50, which are resistant to RHBV and to the feeding damage caused by T. orizicolus, were crossed with the susceptible line WC366 to produce segregating F2:3 populations. The F3 families were scored for their resistance level to RHBV and T. orizicolus. The F2:3 lines of both crosses were genotyped using microsatellite markers. One major QTL on the short arm of chromosome 4 was identified for resistance to RHBV in the two populations. Two major QTL on chromosomes 5 and 7 were identified for resistance to T. orizicolus in the Fd2000 × WC366 and Fd50 × WC366 crosses, respectively. This comparative study using two distinct rice populations allowed for a better understanding of how the resistance to RHBV and its vector are controlled genetically. Simple marker-aided breeding schemes based on QTL information can be designed to improve rice germplasm to reduce losses caused by this important disease.

We describe here the complete genome of Rice hoja blanca tenuivirus. The sequenced isolate was obtained by insect vector transmission from a symptomatic rice sample grown in Colombia. Sequence data from the four RNA components were obtained by deep sequencing (Illumina), and infections were confirmed by enzyme-linked immunosorbent assay and Sanger sequencing.

Background: Toxinology is a field of toxicology involved in studying toxins from animals, plants and microorganisms. In Colombia, in last thirty years, this area has been mainly studied by Programa de Ofidismo/Escorpionismo of the Universidad de Antioquia, however, some other research groups have been also contributed in our knowledge of venoms, toxin, effects and treatments. Objective: highlights the most important findings in toxinology made by Programa de Ofidismo/Escorpionismo and other research groups in Colombia. Methods: we collected and analyze119 manuscripts dealing with the history of ophidiology and toxinology in Colombia. Results: we describe some useful terms to understand the toxinology and their scopes. In addition, we build a brief history of ophidiology beginning with the period corresponding to the discovery of America, and ending with recent findings. Finally, we perform a great description of several results related to toxin isolation, characterization, antivenoms, clinical trials, new species descriptions, pretoemic and transcriptomic, among other. The nineteens was characterized by the study of snakebites, their clinic manifestations and the use of antivenoms. In addition, the ethnopharmacological studies of medicinal plants used in snakebite treatments began to be explored. The 2000s included the newly ethnopharmacology, toxin isolation, clinical trials, inhibitor studies, scorpion venom characterization and scorpion stings features. Finally, from 2010 until today, proteomic and transcriptomic gave the most important findings. Conclusions: Toxinology works in Colombia have contributed in our knowledge about endemic species, clinical manifestations of snakebites and scorpion stings, however, we invite to Colciencias and other funding agencies to have more resources in order to support more researchers in this field, since, snakebite is a public neglected disease and need more attention from governments and academic people. Finally, we still have ignorance about the venoms of some species and their possible mode of action. In addition, given the complexity of venoms, we ignore the potential use of toxins in current biomedicine. Thus, we must continue performing studies in toxinology.