Fenômica e identificação de QTLs para caracteres de raiz em arroz

• Autor(a) principal: Terra, Thiago Gledson Rios
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1244
• topic: Arroz; Oryza sativa L. subesb japônica; Sistema radicular; Plantas - Engenharia genética; QTL; Rice; Oryza sativa L. japonica subesb; Root system; Plants - Genetic Engineering; QTL; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The objectives of this study were to evaluate the root system in genotypes of upland rice by a new methodology in situ; conduct a bioassay to phenotyping root traits in a Core Collection of Rice for Drought (CNAS) and build a genetic map and identification of quantitative trait loci (QTL) that control variables of the root system in rice. The first experiment was conducted in the greenhouse condition whose experimental design was randomized complete block with four replications. Each experimental plot consisted of a PVC pipe with an acrylic tube fitted inside, wrapped with haplustox containing three rice plants. A weekly root scanner (IC-600) was inserted in the acrylic tube and generating an image, in depth of 5 to 25 cm and the other at a depth 25 to 45 cm. These images were quantified by means of software WinRhizo by providing the variable total length of the root, contact area, diameter and volume. The genotypes showed significant differences between them and between depths evaluated through joint analysis for the variables length and contact area. As for the average diameter and volume differences were found between the depths only. The genotype Azucena was superior to the others for the variables length and contact area. When evaluating the sum of the two images for each genotype differences were found between the same for all variables except for diameter. This method proved to be efficient, relatively fast, non-destructive and with the advantage of obtaining data over the period of plant development. The second experiment used 87 accessions belonging to CNAS Embrapa in randomized block design with three replications on condition of the greenhouse. Was used a non- destructive method with scanning images via a scanner root (CI - 600 Root Scan). The roots were quantified with the aid of software WinRhizo, 2008 version. The genotypes that stood out for the condition of the greenhouse in the depth 5-25 cm were Cashew Smooth and Paná. Already at depth 25-45 cm the highlights were the Meruim Ligeiro, Samambaia Amarelo, and Legítimo. Based on 20% dissimilarity between genotypes of CNAS nine groups were formed by the method of grouping the farthest neighbor showing the presence of large variations among the same for root traits. The third ixexperiment was assessed a population F2:3 consisted of 150 families from the cross between IAC 165 x BRS Primavera. Genotyping was performed in the F2 population by 1397 SNPs (Single Nucleotide Polymorphism). These markers were grouped by technique known as DNA chip (or DNA Microarray). For the formation of genetic maps we used a LOD score of 5.0, and for the formation of one QTL LOD above 2.5. A bioassay phenotype in the F3 population was conducted in a randomized block design with three replications under the greenhouse condition. The evaluations of the root system were determined by the generation of images through the scanner root CI-600 and quantification WinRhizo through software. The variables analyzed were length (COM), the contact area in 3D (A3D) and volume (VOL) at depths 5-25 cm (1) and 25- 45 cm (2). The genetic map was composed in 1061 originated SNP markers and had a total length of 1424 cM. The chromosome formed with larger coverage area by the markers was number 3 with 270 cM (170 SNP‟s), followed by chromosome 1 with 249 cM (170 SNP‟s) and 2 with 163 cM (99 SNP‟s). For variables COM (1) COM (2), ACR (1), ACR (2) and VOL (1) were found QTLs on chromosomes 1 and 3. As for the variable VOL (2) were observed two QTLs on chromosome 1. Key words: root methodology, Oryza sativa L. subsp. japonica, core collection of rice, genetic map, identifying QTL.