Strategies for selection and characterization of soybean lines with emphasis on rust tolerance

Abstract

Agriculture in Brazil has experienced an accelerated growth in the last decades, with emphasis on soybeans, the main commodity currently. Parallel to this, phytosanitary problems have affected the efficiency of the crop production. For soybean, the most important disease is Asia rust (ASR), with billion-dollar losses annually, computing the reduction in grain yield and the control costs. Therefore, the aim of this research project is to investigate the genetic tolerance as a strategy of ASR control in soybean segregating populations derived from a recurrent selection program, as well as to select elite lines of high agronomic performance in the presence of the disease. We will evaluate 64 populations F2:5 originated from a 8x8 partial diallel in two contrasting sites. In each location, two similar experiments will be implemented, differing only in rust management (with and without chemical control). Phenotypic selection of thousands of individual plants will be made to compose the F5:6 inbred lines, which will be conducted in augmented block design, also with replicated trials to access the level of tolerance of each genotype. Therefore, 3,286 experimental plots will be measured for several traits. Different statistical strategies (classical analyzes, linear mixed models, and spatial statistics) and phenotyping techniques (agronomic traits and high throughput phenotyping of soybean seeds) will be implemented in order to identify promising lines and provide subsidies to the efficient line selection process in soybean breeding programs. (AU)