Determination of root system architecture variation of drought adapted sorghum genotypes using high throughput root phenotyping

Sorghum bicolor (L.) is an important cereal crop in Ethiopia primarily growing as food grain crop. In spite of the huge genetic potential, productivity of sorghum is low due to frequency of drought occurrence. Root system architecture influences the amount of water important for maintaining crop yield under moisture stress. This study was conducted with the objective of estimating of genetic variability of 214 sorghum genotypes for root and shoot traits during seedling stage. The experiment was conducted at greenhouse of Horticulture and Plant science Department of Jimma University using randomized complete block design. Analysis of variance showed that highly significant difference among the genotypes (P < 0.01) in all studied traits. Root angle ranged between 14.5 (Acc#23650) and 27.37 degrees (Acc#6723). Root number ranged between 6 and 15, root length between 40 and 72 cm and root to shoot ratio ranged between 0.17 and 0.78. Genotypes from Ethiopian Biodiversity (IBC) and ICRISAT were showed more root angle genetic variations. Similarly for other root system architecture (RSA) traits such as root length, root number and root dry weight, Ethiopian Biodiversity (IBC) and International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) genotypes showed more genetic diversity than the released varieties. Phenotypic coefficient of variation (PCV) was between 29.19% for leaf area and 13.46% for root length, and genotypic coefficient variation (GCV) was 28.19% for leaf area and 11.94% for root angle. Estimates of broad sense heritability were between 40% for root dry weight and 94.18% for leaf area. Generally the information generated from this study could help to identified promising genotypes with suitable root traits for potential breeding under specific environmental conditions.

Automated summary

Sorghum bicolor is an important cereal crop in Ethiopia, but its productivity is hindered by drought. This study assessed the genetic variability of 214 sorghum genotypes for root and shoot traits, finding that Ethiopian Biodiversity and ICRISAT genotypes displayed more genetic diversity in root system architecture traits. Phenotypic and genotypic coefficient variations varied among traits, with broad sense heritability ranging from 40% to 94.18%. The findings can help identify promising genotypes with suitable root traits for potential breeding under specific environmental conditions.