Genomic prediction and genome-wide association in rubber tree, main renewable source of rubber production

• Grant number: 19/13452-3
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): February 01, 2020
• Effective date (End): January 31, 2022
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal researcher: Anete Pereira de Souza
• Grantee: Stephanie Karenina Bajay
• Home Institution: Centro de Biologia Molecular e Engenharia Genética (CBMEG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The high price of oil and the growing interest in consuming raw material from renewable sources has increased the demand for natural rubber, which that the only commercial source is the rubber tree (Hevea brasiliensis). Brazil came from a situation which was the original center of production of rubber and had the greatest diversity, became the largest producer of it and now is importing most of what consumes. The rubber plantations implanted in the State of São Paulo resumed the growth of the country's crop, despite still contributing only 1.44% of the natural rubber consumed worldwide. To make possible an increase of the heveculture in new potential areas investment in the selection of superior clones is necessary. The multiplication of the clones is done using grafting and the uniformity in the performance of the clones is of great importance for the production of latex and its industrial purposes. However, although the grafting method characterizes a genetic-cultural strategy to ensure that the grafting of a monoclonal block is isogenic, this uniformity expected by the vegetative propagation in the rubber groves has not been observed. Thus, high coefficients of variation for vigor and rubber production have been observed among different clones and even within the same clonal varieties. However, there are no studies that use estimates of genetic and phenotypic parameters to understand this variation found between the vigor and productivity variables in rootstocks. In this context, the convergence of genomic genotyping technologies with quantitative genetics extends the potential to elucidate the molecular mechanisms of latex production. The present work proposes: i) the application of genomic prediction (PG) in rootstock to select the best combination of graft and rootstock based on latex production and (ii) broad genomic association (GWAS) in graft/rootstock association, to identify chromosomal regions and genes related to characteristics of economic importance, such as latex production. As a result of the application of PG and GWAS to rubber rootstocks, it is expected to accelerate the selection gains, reducing the time and cost of a breeding cycle through early selection. In addition, the associations of markers found in regions of quantitative locus in rootstocks can be applied in breeding programs via marker-assisted selection, in addition to directing the identification of genes that are related to latex production. (AU)