Correlation and combining ability of main chemical components in sorghum stems and leaves using cytoplasmic male sterile lines for imporving biomass feedstocks

Authors: ZHOU, FANGYUAN - China Agriculture University; HE, SIYANG - China Agriculture University; Wang, Ming; TANG, CHAOCHEN - China Agriculture University; XU, YI - China Agriculture University; FAN, FAN - Inner Mongolian Agriculture University; XIE, GUANG HIU - China Agriculture University

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2021
Publication Date: 9/1/2021
Citation: Zhou, F., He, S., Wang, M.L., Tang, C., Xu, Y., Fan, F., Xie, G. 2021. Correlation and combining ability of main chemical components in stems and leaves based on cytoplasmic male sterile lines of sorghum for biomass feedstocks. Industrial Crops and Products. 167:113552. https://doi.org/10.1016/j.indcrop.2021.113552.
DOI: https://doi.org/10.1016/j.indcrop.2021.113552

Interpretive Summary: Sorghum is a versatile crop that can be grown for sugar content and biomass to produce renewable biofuels. Sugar and biomass components such cellulose, hemicellulose, lignin, and ash of leaves and stems are used to generate bioethanol and other fuels. While selective breeding results in lines with optimized traits, repeated inbreeding of these lines can cause deleterious reductions in genetic diversity. To counteract this, different inbred lines can be crossed with one another to increase genetic variability and improve crop traits due to the increased vigor of the hybrids. To test the effects of hybridization (heterosis), we crossed various sorghum lines and measured the hybrids for the different traits related to biofuel production. Stems showed a higher correlation in each of the traits than leaves. Additionally, as soluble sugar increased, other biomass traits such as cellulose and lignan content decreased. Finally, cellulose had a positive correlation with hemicellulose and lignin. This indicates that there is a tradeoff in selecting lines with higher sugar content verses those with increased biomass traits. Based on this analysis, specific lines were selected to be parents for either increased sugar or biomass in hybrid breeding.

Technical Abstract: Better understanding the genetic basis that governs inheritance of biomass quality traits may help to improve sorghum (Sorghum bicolor (L.) Moench) varieties for energy purposes. Combining ability studies were conducted using three restorer lines (male) and 60 cytoplasmic male sterile (CMS) lines (female) at two locations in China during 2017 and 2018. Either the entries or the environments significantly affected concentrations of soluble sugar, cellulose, hemicellulose, lignin and ash in both stems and leaves of sorghum. Stems exhibited a higher coefficient of variation level than leaves for each chemical component. The broad-sense and narrow-sense heritability indicate predominance of the additive gene effect on the chemical components in stems and leaves. This investigation is the first to evaluate the combining ability effects on soluble sugar, cellulose, hemicellulose, lignin, and ash in stems and leaves of sorghum. For stems and leaves, GCA on soluble sugar exhibited highly and significantly negative correlations with GCA on cellulose, hemicellulose, lignin. Significantly positive correlations of GCA were found between cellulose, hemicellulose, and lignin. The GCA on ash exhibited a significantly negative correlation with soluble sugar but positively with hemicellulose in stems, whereas it had significantly negative correlation with soluble sugar, cellulose, and hemicellulose. Eleven and six female lines were selected for hybrid biomass type and sweet type breeding, respectively.