Genetics of Pre-anthesis Spike Development in Barley (Hordeum vulgare L.)

In recent years Genome-Wide Association Studies (GWAS) have become more popular and represent a powerful approach for mapping complex agronomical traits with high, unprecedented genetic resolution for gene identification. In this study, we used a worldwide spring barley collection (224 accessions: 128 two- and 96 six-rowed; Pasam et al., 2012, BMC Plant Biol 12, 16) which has been genotyped with the latest Illumina 9K SNP chip of barley (Comadran, Kilian et al., 2012, Nature Genetics in press) to study pre-anthesis spike development in barley, one of the most important phases highly correlated with yield potential and final yield. To this end, we manually dissected more than 2700 plants at different developmental stages (awn primordium, tipping, heading and anther extrusion) to phenotype more than 70 traits related to morphology, physiology, growth rates, yield and yield components. Experiments were conducted under controlled greenhouse conditions (16h LD with 14/20 ^oC night/day; 4 weeks vernalization treatment) where heritability values ranged between 0.75-0.96 for most traits. One important aim of the project is to unravel the genetic basis of spikelet and floret abortion during barley spike development. We found a negative relationship between spikelet/floret survival and leaf area of the main culm. Moreover, this data set will also allow the genetic dissection of pre-anthesis spike development prior to flowering, thereby revealing loci contributing to flowering time at different developmental stages. Overall, GWAS of spike development and flowering time may provide novel links for breeding.