| dc.description.abstract | Increasingly serious greenhouse gas effects and soil erosion have raised demand for crops with robust belowground systems and carbon sequestration ability. Rhizomes are photoassimilate storage plant tissues, and their biomass can function as important targets for increasing the carbon sequestration capacity of perennial crops. Sorghum is an ideal crop, having rhizomatous wild relatives such as Sorghum propinquum (Kunth) Hitchc that have the same ploidy as annual cultivars.
In this study, twelve F3:4 heterogeneous inbred families (HIFs) derived from a Sorghum bicolor (L.) Moench and S. propinquum cross were planted in a greenhouse, and two of their F4:5 HIF progeny were employed in field cultivation. Thirteen traits, as well as an additional four traits, were investigated in F4:5 and F3:4, respectively. High-range variations were found in most of the traits, with many also showing a high heritability. The correlation analysis suggested a positive correlation between rhizome biomass and aboveground biomass, as well as grain yield.
A bulked segregant analysis (BSA) approach was proposed and used for screening the linked markers related to rhizome biomass, whereas no “rhizome biomass” specific simple sequence repeat (SSR) markers were identified, and the presence or absence of rhizome was finally analyzed. Twenty linked markers were found for rhizome presence, which roughly defined eight target genomic regions. Three of the eight regions were overlapped by several rhizome-related quantitative trait loci (QTLs ), while four regions partially coincided with vegetative branching QTLs, which were reported in other studies. Five potentially novel regions were found in total.
Our results suggested a situation in which rhizome biomass, aboveground biomass, and grain yield can be potentially improved at the same time, in addition to developing molecular tools both for breeding pipeline and next-step QTL mapping. | |
