Plant & Animal Genomes XVII Conference Plant & Animal Genomes XVII ConferenceJanuary 10-14, 2009
Town & Country Convention Center
San Diego, CA
Matthew P Reynolds1,2 , Yann Manes1 , Peter Langridge2
Physiological approaches that can be used to increase rates of genetic gains include (i) strategic trait-based crossing to combine complementary traits in progeny, (ii) high throughput phenotyping to enrich for desirable alleles in early generations, (iii) exploration of genetic resources to broaden the genetic base. One of the bottlenecks in applying new genetic technologies to crop research is precision phenotyping. In the case of gene discovery within mapping populations, high throughput phenotyping techniques -such as thermal imaging for canopy temperature and spectral reflectance for ground cover and stem carbohydrates- permit large numbers of genotypes to be screened with high efficiency. Confounding factors still need to be resolved in studies where genes of major effect are not controlled. Major genes -Rht, Ppd, Vrn- not only affect the crops morphology but also may lead to interactions between phenology and, for example, availability of soil water at key growth stages. These factors may cause QTLs to be falsely identified as well as complicating the already difficult challenge of dissecting genotype x environment interaction. New generations of mapping populations are being developed that contrast in drought adaptive traits but not in flowering time or height. However, progeny of bi-parental crosses still encompass the problem that transgressive segregation of parental alleles usually result in some agronomically inferior genotypes and, therefore, alleles long since adopted in plant breeding may mask more subtle effects. Association genetics provides a potential alternative where genetically diverse but elite cultivars can be used for gene discovery.