Association mapping of genetic resources: Achievements and future perspectives

Abstract

Association mapping studies in plants contribute to not only detecting the genetic basis of variation in physiological, developmental, and morphological traits (e.g., flowering time, plant height, grain quality, and nutrient content) but also bringing together researchers to assemble core collections and develop genetic platforms for genotyping, phenotyping, analysis, and interpretation. The establishment of the unified mixed model greatly facilitated association mapping studies in plants and further methodology work in general. Association mapping is well positioned to exploit the advances in next generation genomic technologies and high-throughput phenotyping. Genome-wide association studies (GWAS) are expected to increase dramatically once genome sequences of all major crop species are obtained. Moving forward, researchers in plant genetics and related disciplines need to develop improved genetic designs and computational tools to address several challenges such as missing heritability, new gene identification, genotyping-by-sequencing, and rare alleles. In this chapter, we describe major progress in understanding population structure, advancements in design and implementation of association mapping, and summarize examples of association mapping in maize, rice, Arabidopsis, wheat, barley, soybean, and sorghum. Finally, major opportunities with potential implications in plant genetics are discussed.