Assessment of agro-morphological variability of dry-season sorghum cultivars in Chad as novel sources of drought tolerance

Authors: NAOURA, GAPILI - Institute For Research And Development In Agri-Environment(IRDA); NERBEWENDE, SAWADOGO - Institute For Research And Development In Agri-Environment(IRDA); ATCHOZOU, EYANAWA - Institute For Research And Development In Agri-Environment(IRDA); Emendack, Yves; HASSAN, MAHAMAT - Institute For Research And Development In Agri-Environment(IRDA); Echevarria Laza, Haydee; TABO, RAMADJITA - Institute For Research And Development In Agri-Environment(IRDA)

Submitted to: Nature Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2019
Publication Date: 12/20/2019
Citation: Naoura, G., Nerbewende, S., Atchozou, E., Emendack, Y., Hassan, M., Echevarria Laza, H.J., Tabo, R. 2019. Assessment of agro-morphological variability of dry-season sorghum cultivars in Chad as novel sources of drought tolerance. Nature Scientific Reports. 9:19581. https://doi.org/10.1038/s41598-019-56192-6.
DOI: https://doi.org/10.1038/s41598-019-56192-6

Interpretive Summary: One of the most significant limitations to breeding for drought stress tolerance in sorghum is the few available sources of genetic diversity. A collaborative research by scientists from ARS and three African countries evaluated an untapped diverse group of sorghum cultivars commonly known as dry-season sorghum. These sorghum cultiars are from three regions in Chad, where sorghum is predominantly cultivated following the receding of flood waters with limited to no precipitation over the rest of the growing season. Five cultivars (Farine, Gogmi Rouge, Gogoumi , Glinding, and Gogoum jaune) with desirable traits were identified and selected as novel sources for breeding to develop elite lines.

Technical Abstract: Dry-season sorghum is a type of sorghum whose establishment ends at the end of the rainy season and its development takes place during the dry and cold harmattan period. Its root system is particularly well developed with deep penetration for water withdrawal. This study was conducted to assess the level of genetic diversity present among dry-season sorghum in Chad's Sudanese zone using phenotypic traits, and to identify new sources of drought tolerance that could be used in sorghum breeding programs. A high variability in qualitative traits was observed except for the botanical race which showed that all cultivars were of durra race. It was also observed that most cultivars had compact panicles (66.67%), mostly black glumes (66.67%), glume hairiness (58.33%) and did not have aristation (91.67%). Most qualitative traits showed a coefficient of variation of less than 30%, and the analysis of the variance showed that at 0.1% probability, there were significant differences between cultivars for all traits except botanical race. It was observed that the potential productivity of dry-season sorghum of this collection was strongly related to their staygreen characteristic; a trait of enormous importance in breeding for postflowering drought tolerance in sorghum. Plant height was highly heritable (91.9%), followed by the peduncle length (90.2%), panicle length (87.5%) and the internodes number (86.5%). Structuring of diversity separated the cultivars into four statistically distinct groups; with group 2 clustering cultivars with panicle productivity, early maturity and high staygreen, and other traits that contribute to the performance of cultivars. The findings will help to enhance the selection and production of dry-season sorghum in Chad and also provide alternative sources for staygreen introgression into the larger sorghum breeding community.