Multivariate analysis of root system architectural traits of sorghum for drought tolerance

The root system architecture (RSA) of sorghum is a major morphological trait, which intensely influences the capacity to access soil moisture and forage nutrients under drought conditions. On this basis, the study is to group a set of potential parents based on the information obtained from multivariate analysis of 214 sorghum genotypes using root system architecture. This experiment was conducted using a high-throughput root system phenotyping custom root chamber method in the greenhouse at the Horticulture and Plant Science Department at Jimma University that was arranged in a randomized complete block design with three replications. The sorghum genotypes in this study were grouped into eight distinct clusters based on their root system architecture. Cluster CL-II had the highest number of genotypes, while clusters CL-III and CL-VI had the lowest number of genotypes. The genetic distance between clusters CL-III and VIII was the highest, indicating that these clusters had the most different root traits. On the other hand, clusters CL-V and CL-VII had the lowest genetic distance, suggesting that they had low variation. CL-III had a combination of a narrowest root angle and the longest root length. The principal component analysis (PCA) shows that Acc#220253(58), Acc#220254(#59), Acc#234102(102), Acc#235791(#108), Acc#235811(#118), and Acc#7125(#193) are the most diverging genotype that belonging to different and distantly located clusters. So that these accessions could have higher probabilities of producing heterotic hybrids or superior progenies during hybridization, they could also be taken into consideration as better parents for an efficient future breeding programe.