Phenotypic correlation between root traits in sweet potato clones

Sweet potato (Ipomoea batatas L.) is a tuberous vegetable of great economic and nutritional importance in Brazil and worldwide. This is due to the fact that there is versatility in its use, both for human and animal consumption.Despite its importance, studies aimed at improving the species are still in their infancy. One of the crucial parameters in plant breeding efforts is the correlation between characters of interest.It estimates the linear association between such traits and allows for indirect improvement for characteristics with low heritability or difficult measurement.Thus, the aim of this study was to estimate the phenotypic correlations between quantitative and qualitative traits in sweet potato clones from the Sweet Potato Breeding Program at the Federal University of Viçosa.The clones were obtained through recombination in open pollination, and a population of ten half-sibling families was evaluated, totaling 966 experimental clones.The clones were tested in a field condition using an augmented block design with interspersed checks, which included: 'Brazlândia Branca' with light cream-colored flesh, 'Beauregard' with orange flesh, and 'SCS370 Luiza' with purple flesh coloration.The evaluated traits were total number of roots (NTR), number of marketable roots (NRC), total root yield (PRT), marketable root yield (PRC), percentage of marketable roots (%RC), and soil pest resistance (RP). The data were subjected to Pearson correlation for all traits, except for RP, as it was not significant by the F-test and for a correlation to be correctly calculated, there must be variation in both characteristics.According to the literature, the interpretation of correlations is divided into: very weak (0.00 to 0.19), weak (0.20 to 0.39), moderate (0.40 to 0.69), strong (0.70 to 0.89), and very strong (0.90 to 1.0). Positive and moderate estimates were obtained for NTRxPRT (0.40**), NTRxNRC (0.49**), NRCxRC (0.66**), NRCxPRT (0.44), PRTxPRC (0.58**), and PRCxRC (0.67), as well as a very strong correlation between NRC and PRC with a significant value of 0.85.The results demonstrate that selecting clones with high total tuberous root production may be associated with higher marketable root yield, without the need for both assessments. Thus, this information can assist in future work and lead to a reduction in the number of evaluations, as well as saving time and labor.