To identify quantitative trait loci (QTL) controlling heat tolerance in rice, the progeny of BC 1 F 1 and F 2 populations derived from an IR64 · N22 cross were exposed to 38/24°C for 14 days at the flowering stage, and spikelet fertility was assessed. A custom 384-plex Illumina GoldenGate genotyping assay was used to genotype the F 2 and selected BC 1 F 1 plants. Four single nucleotide polymorphisms were associated with heat tolerance in the BC 1 F 1 population using selective genotyping and single marker analysis, and four putative QTL were found to be associated with heat tolerance in the F 2 population. Two major QTL were located on chromosome 1 (qHTSF1.1) and chromosome 4 (qHTSF4.1). These two major QTL could explain 12.6% (qHTSF1.1) and 17.6% (qHTSF4.1) of the variation in spikelet fertility under high temperature. Tolerant allele of qHTSF1.1 was from the susceptible parent IR64, and that of qHTSF4.1 was from tolerant parent N22. The effect of qHTSF4.1 on chromosome 4 was confirmed in selected BC 2 F 2 progeny from the same IR64 · N22 cross, and the plants with qHTSF4.1 showed significantly higher spikelet fertility than other genotypes.

The current Colombian population is the result of genetic admixture between Native Americans, Europeans and Africans. Around 82% of the population is considered admixed, 15% are Afro-Colombians and just 3% are Native Americans. There are about 81 native groups in Colombia. In this work, a sample of 121 non-related individuals from three Native American groups were analysed for 46 ancestry informative InDel markers. One of these groups was the Pijaos that, because of their combative nature, was almost exterminated during European conquest and colonial times. The other two studied groups belong to communities that have been less subjected to admixture with non-Natives. The Barí, known as "Motilones" or "Dobukubi", is a Native group that inhabits the Serranía del Perija, Norte de Santander, since pre-Colombian times. They still keep their original language, the Barí-ara, which belongs to the Chibcha family. We have also studied a sample of Natives from Guainía, formed by different groups that migrated from the Amazonia and Orinoquian regions, including the Desana, Curripaco, Puinave, Cubeo, Guaunano and Tucano, all belonging to Tucano and Arawak linguistic groups. This study allow determining genotypic and allelic frequencies for 46 ancestry informative InDels and to estimate Native American, European and African admixture proportions in three Colombian native communities. The results showed a very low European and African admixture in the Barí and Guainia native groups in contrast to the high levels of admixture presented by the Pijao.

No abstract