Combining high throughput phenotyping and multivariate analysis to assess fruit quality traits in southern highbush blueberry (V. corymbosum interspecific hybrids) germplasm collection

Authors: Babiker, Ebrahiem; Stringer, Stephen; Sakhanokho, Hamidou; MUNOZ, PATRICIO - University Of Florida

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2023
Publication Date: 6/16/2023
Citation: Babiker, E.M., Stringer, S.J., Sakhanokho, H.F., Munoz, P. 2023. Combining high throughput phenotyping and multivariate analysis to assess fruit quality traits in southern highbush blueberry (V. corymbosum interspecific hybrids) germplasm collection. HortScience. 58(7):750-755. https://doi.org/10.21273/HORTSCI17185-23.
DOI: https://doi.org/10.21273/HORTSCI17185-23

Interpretive Summary: Breeding blueberry cultivars with enhanced fruit quality requires simple, accurate and cost-effective assays to select elite individual plants. For this purpose, we have used numerous analytical techniques to assess different fruits quality traits. Berry diameter and firmness were assessed simultaneously using a Firmness Tester. While the discrete analyzer was used to estimate pH, total polyphenol, total acids, D- glucose, D-fructose, total glucose, and total sugar content in 188 southern highbush blueberry selections and cultivars over two years. Characterizing the blueberry germplasm collection revealed significant variation between genotypes demonstrating the potential of the collection for breeding high quality cultivars. Glucose and fructose were the predominant sugars, and they were in a range of 32.14-64.72 and 28.61-69.63 mg/ml respectively. Total sugars content ranged from 62.22 to 131.15 mg/ml. Correlation analysis showed a strong positive correlation between glucose, fructose, total glucose, and total sugar content measured with the discrete analyzer and total soluble solids assessed as Brix. The tight relationship between D-glucose, D-fructose, total glucose, and total sugars is useful in indirect selection. The titratable acidity was positively correlated with total acids and strong positive correlation between berry diameter and berry weight was detected. The strong correlation will allow breeders to reduce the cost of screening and speed the screening process. Cluster analysis showed that the blueberry genotypes fell into two major groups. Cluster-I comprised genotypes with the highest amounts of total acids, pH, polyphenol, D-glucose, D-fructose, total glucose, and total sugar whereas Cluster-II has genotypes with distinctly lower amounts of tested compounds and larger berries. Information obtained from this study is critical to identify superior genotypes for future crosses and advance evaluation. In addition, the firmness tester and discrete analyzer used in this study were invaluable in improving the efficiency and precision of phenotyping.

Technical Abstract: Breeding blueberry cultivars with enhanced fruit quality requires simple, accurate and cost-effective assays to select individuals from segregating populations. In this study, berry diameter, berry weight, firmness, pH, total polyphenol, total acids, D- glucose, D-fructose, total glucose, and total sugar content were quantified in 188 southern highbush blueberry selections and cultivars over two years. Significant variation between years, genotype, and year x genotype interaction was detected for all traits. Glucose and fructose were the predominant sugars, and they were in a range of 32.14-64.72 and 28.61-69.63 mg/ml respectively. Total sugars content ranged from 62.22 to 131.15 mg/ml. Correlation analysis showed a strong positive correlation between total sugar content measured with the discrete analyzer and total soluble solids assessed as Brix (r2= 0.96). In addition, glucose, fructose, and total glucose showed high and positive correlation between them and with the total sugar content. The titratable acidity was positively correlated with total acids (r2= 0.60) and strong positive correlation between berry diameter and berry weight (r2= 0.94) was detected. Principal component analysis showed that PC1 explained 44.9% of the variation and the major contributing traits for diversity were D-fructose, D-glucose, total glucose, and total sugars. PC2 accounted for 21.2% of the variation and was mainly attributed to berry weight and diameter. Cluster analysis showed that the blueberry genotypes fell into two major groups. Cluster-I comprised genotypes with the highest amounts of total acids, pH, polyphenol, D-glucose, D-fructose, total glucose, and total sugar whereas Cluster-II has genotypes with distinctly lower amounts of tested compounds and larger berries. Information obtained from this study is critical to identify superior genotypes for future crosses and advance evaluation. In addition, the firmness tester and discrete analyzer used in this study were invaluable in improving the efficiency and precision of phenotyping.