Assessment of photoperiod sensitivity and the effect of sowing date on dry-season sorghum cultivars in Southern Chad

Authors: Emendack, Yves; SAWADOGO, NERBEWENDE - Joseph Ki-Zerbo University; RAMADJITA, TABO - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); LAZA, HAYDEE - Texas Tech University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2023
Publication Date: 3/21/2023
Citation: Emendack, Y., Sawadogo, N., Ramadjita, T., Laza, H. 2023. Assessment of photoperiod sensitivity and the effect of sowing date on dry-season sorghum cultivars in Southern Chad. Agronomy Journal. 13(3). Article 932. https://doi.org/10.3390/agronomy13030932.
DOI: https://doi.org/10.3390/agronomy13030932

Interpretive Summary: Sensitivity to day length is a major limitation to utilizing sorghum germplasm from West and Central Africa in breeding for valuable traits related to abiotic stress tolerance. Collaborative research by scientists from Lubbock, TX and three African countries evaluated an untapped diverse group of sorghum cultivars commonly known as dry-season sorghum from three regions in Chad, where they are predominantly cultivated following the receding of flood waters with limited to no precipitation over the rest of the growing season. The variability in day-length sensitivity was assessed from early and delayed plantings, by characterizing traits related to plant development and yield in a two-year trial. Cultivars showed strong differences in day-length sensitivity, with early planting favoring higher grain yields than delayed planting. Cultivars less sensitive to day length and with desirable quantitative and qualitative traits were identified and selected as novel sources for trait introgression into elite lines through breeding.

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 in photo-periodism present among dry-season sorghum cultivars in Chad's Sudanese zone. Delaying sowing significantly decreased potential yield, duration of vegetative phase, and biomass in the two years of experiments. All assessed dry-season sorghum cultivars were photo-period sensitive and delayed sowing decreased the photo-period sensitivity. On average, during flowering time, day length ranged between 9.25 and 11.05 hr in the two years of experiments. Average monthly maximal and minimal air temperatures were 37 and 36.8C and 20.2 and 19.3C for 2013 and 2014 respectively. These findings will help to enhance the selection and production of dry-season sorghum in Chad. Additionally, the observed variability in photo-period sensitivity from delayed planting provides opportunity to use Chadian dry-season sorghum as a valuable source for introgression of abiotic stress tolerant traits of interest to the larger sorghum breeding community.