Combining ability of cytoplasmic male sterility on yield and agronomic traits of sorghum for grain and biomass dual-purpose use

Authors: HE, SIYANG - China Agricultural University; TANG, CHAOCHEN - China Agricultural University; Wang, Ming; LI, SONGBO - China Agricultural University; DIALLO, BOUBACAR - China Agricultural University; XU, YI - China Agricultural University; ZHOU, FANGYUAN - China Agricultural University; SUN, LEI - China Agricultural University; SHI, WENJUN - China Agricultural University; XIE, GUANG HUI - China Agricultural University

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2020
Publication Date: 9/9/2020
Publication URL: https://handle.nal.usda.gov/10113/7108325
Citation: He, S., Tang, C., Wang, M.L., Li, S., Diallo, B., Xu, Y., Zhou, F., Sun, L., Shi, W., Xie, G. 2020. Combining ability of cytoplasmic male sterility on yield and agronomic traits of sorghum for grain and biomass dual-purpose use. Industrial Crops and Products. 157:112894. https://doi.org/10.1016/j.indcrop.2020.112894.
DOI: https://doi.org/10.1016/j.indcrop.2020.112894

Interpretive Summary: Sorghum is a versatile crop that can be grown not only as a grain for food, animal feed, or other industrial uses, but also for biomass to produce renewable biofuels. Extensive sorghum breeding can result in lines with optimized traits, but the repeated inbreeding of these lines can cause negative traits to build up as well. To counteract this, different inbred lines can be crossed with one another to increase genetic variability and improve crop yield due to the increased strength and vigor of the hybrids. To test the effects of hybridization (heterosis), we crossed various sorghum lines and measured different yield traits for grain and biomass of the resulting hybrids. Some traits showed a higher sensitivity to hybridization in that the effects (general combining ability) were greater than they were on other traits. Traits that were strongly affected included plant height and harvest index, while traits that were only weakly affected included grain yield, 100-grain weight, and maturity rate. Plant height had the highest sensitivity to hybridization and also was the most important trait correlated with biomass production. Furthermore, certain combinations of the sorghum lines were identified as have greater hybridization effects. Information on heterosis of sorghum germplasm is important for improving sorghum as a food grain and as biomass for a renewable fuel source.

Technical Abstract: Sorghum [Sorghum bicolor (L.) Moench] is a C4 high-yielding crop used not only to produce grains for food, feed, and industrial uses but also biomass (i.e., leaf and stem) for biofuels’ production. To take better advantage of its heterosis for both grain and biomass dual-purpose use, the combining ability of 34 cytoplasmic male sterile lines (female) were tested with 3 cytoplasmic male fertile or restore lines (male), using the North Carolina design (NCII), at Zhuozhou (Hebei province) and Jiexiu (Shanxi province) in northern China for two years (2017 and 2018). We found that the hybrids exhibited a grain yield of 0.3~14.0 t ha-1 and had an aboveground biomass yield (AGBY) of 9.6~109.9 t ha-1 across both sites in 2017 and 2018. The genotype used and site × genotype interactions significantly affected the yield and agronomic traits. With respect to their grain and biomass dual-purpose use, the tested 34 female lines revealed that plant height, center of gravity height, productive tiller rate, and harvest index were strongly GCA- (general combining ability) sensitive, whereas stem width, days to maturity, AGBY, and grain width were medium GCA-sensitive, and grain yield, 100-grain weight, days between heading and maturity, and grain bulk density were all weakly GCA-sensitive. The GCA effect on grain yield was positive and significantly correlated with that of productive tiller rate, AGBY, and harvest index. The GCA effect on AGBY had a positive, significant correlation with that on plant height, center gravity height, productive tiller rate, and days to maturity, yet negative with the effect on 100-grain weight and grain width. Plant height was the most GCA-sensitive trait and the most important for biomass production. Female lines AMP418, AMP431, AMP434, AMP443, AMP495, AMP496 and the male line X097 were selected as being high-GCA effect germplasm. This selection from newly introduced cytoplasmic male sterile lines holds promise for accelerating sorghum’s genetic improvement for its dual-purpose use as grain for food and biomass for biofuel.