The Paradox and Potential Opportunity of Diversity and Abundance.

Significant financial investments are being made globally to acquire, conserve, and use genetic resources for crop improvement.  At the same time, a paradox exists where we commonly note that the nutritional/compositional diversity of most foods/feeds derived from crop plants is low.  Why has this contradiction occurred and how do we change the situation for the better?  Coordinated development of both genetic and genomic resources, focused on organ and/or whole-plant compositional traits, can provide the foundation to advance the use of genetic resources to expand the breadth of options for improved, accessible quality traits.  Our ability to employ DNA sequencing/genotyping, high-throughput phenotyping, and ‘big data’ management and analysis makes the potential value of ex situ genebanks of significantly greater value as we attempt to discover and introgress useful genes and genotypes.  We present two case studies highlighting how coordinated development of germplasm and genomic information is used to establish the breadth of variation available and simultaneously provide preliminary insights to the genetic bases of these desired traits.  Improving sorghum as a source of food, feed, and fuel, we are attempting to affect how carbon is fixed, translocated, partitioned, and deposited in target organs.  Dissection of grain yield and quality components has identified useful genetic variation to improve sorghum grown for both food and feed uses.  Importantly, much of the genetic variation underlying grain quality traits does not adversely affect grain yield and vice versa.  Similarly, improving sorghum as a forage and bioenergy feedstock requires the retention of sorghum’s high yield potential while increasing the C₆:C₅ carbon ratio and reducing lignin. Genomic analysis of diverse germplasm has identified targets for biomass quality improvement but the data suggest that improving quality may reduce yield due to an increased susceptibility to disease and insect pressure and lodging.