Evaluation of Selected Zambian Popular Sweet Potato Genotypes for Response to Sweet Potato Virus Disease

Aim: The objective of this study was to determine the effect of sweet potato virus disease (SPVD) on the beta carotene content, tuber weight and vine weight of selected popular sweet potato genotypes.

Study Design: The experiment was laid as a randomized complete block design (RCBD) with three replications.

Place and Duration of Study: The experiment was conducted for two cropping seasons (2015/16 and 2016/17) at the Zambia Agriculture Research Institute in Chilanga district of Zambia.

Methodology: The uninfected (control) genotypes of Kanga, Chiwoko and Chingovwa were evaluated alongside their SPVD infected genotypes. Genotypic infection was confirmed using molecular approaches, and data was collected at harvest on beta carotene content, tuber weight and vine weight.

Results: The results showed that SPVD affects the yield and beta carotene content of sweet potato. Significant differences (P< .001) for yield performance and beta carotene were observed. The yield reduction in percentage across seasons for all genotypes between the uninfected and infected genotypes ranged from 77% to 79% and 67% to 76% for tuber weight and vine weight respectively. Only Chiwoko exhibited higher levels of beta carotene among the genotypes. However, the SPVD infected Chiwoko genotype compared to the uninfected treatment produced mean beta carotene content of 39.1 µg/g and 91.5 µg/g respectively.

Conclusion: SPVD reduces the tuber weight, vine weight and beta carotene content in infected sweet potato genotypes.