Biofuel made from agricultural products has the potential in contribute to a stable supply of fuel for growing energy demands. Some salient plant traits, such as stem diameter and water content, and their relationship to other important biomass-related traits are so far poorly understood. Here, we performed QTL mapping for three stem diameter and two water content traits in a S. bicolor BTx623 x IS3620c recombinant inbred line population of 399 genotypes, and validated the genomic regions identified using genome-wide association studies (GWAS) in a diversity panel of 354 accessions. The discovery of both co-localized and non-overlapping loci affecting stem diameter traits suggests that stem widths at different heights share some common genetic control, but also have some distinct genetic influences. Co-localizations of stem diameter and water content traits with other biomass traits including plant height, flowering time and the ‘dry’ trait, suggest that their inheritance may be linked functionally (pleiotropy) or physically (linkage disequilibrium). Water content QTL in homeologous regions resulting from an ancient duplication event may have been retained and continue to have related functions for an estimated 96 million years. Integration of QTL and GWAS data advanced knowledge of the genetic basis of stem diameter and water content components in sorghum, which may lead to tools and strategies for either enhancing or suppressing these traits, supporting advances toward improved quality of plant-based biomass for biofuel production.

农产品制成的生物燃料具有潜力，可以为不断增长的能源需求稳定地供应燃料。迄今为止，人们对一些显着的植物性状，例如茎直径和水分含量，以及它们与其他重要的生物量相关性状的关系知之甚少。在这里，我们对双色链球菌的三个茎直径和两个水分特征进行了QTL定位BTx623 x IS3620c 399个基因型的重组近交系种群，并在354个种质的多样性组中验证了使用全基因组关联研究（GWAS）鉴定的基因组区域。影响茎直径性状的共定位和不重叠位点的发现表明，不同高度的茎宽共享一些共同的遗传控制，但也具有一些独特的遗传影响。茎直径和含水量性状与其他生物量性状（包括株高，开花时间和“干”性状）的共定位表明，它们的遗传可能在功能上（多效性）或物理上关联（连锁不平衡）。古代复制事件造成的同源区域中的水分含量QTL可能已经保留，并在估计9600万年的时间里仍具有相关功能。