Variation in mineral element composition of landrace taro (Colocasia esculenta) corms grown under dryland farming system in South Africa

Abe Shegro Gerrano; Isack Mathew; Admire It Shayanowako; Stephen Amoo; John Jason Mellem; Willem Jansen Van Rensburg; Michael Wolday Bairu; Sonja Louise Venter

doi:10.1016/j.heliyon.2021.e06727

Variation in mineral element composition of landrace taro (Colocasia esculenta) corms grown under dryland farming system in South Africa

Heliyon. 2021 Apr 8;7(4):e06727. doi: 10.1016/j.heliyon.2021.e06727. eCollection 2021 Apr.

Authors

Abe Shegro Gerrano^{1

2}, Isack Mathew³, Admire It Shayanowako³, Stephen Amoo^{1

4

5}, John Jason Mellem⁶, Willem Jansen Van Rensburg¹, Michael Wolday Bairu¹, Sonja Louise Venter¹

Affiliations

¹ Agricultural Research Council-Vegetables, Industrial and Medicinal Plants, Private Bag X293, Pretoria 0001, South Africa.
² Faculty of Natural and Agricultural Sciences, School of Agricultural Sciences, Crop Science Department, North-West University, Private Bag X2046, Mmabatho, 2790, South Africa.
³ African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa.
⁴ Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, South Africa.
⁵ Indigenous Knowledge Systems Centre, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2790, South Africa.
⁶ Department of Biotechnology and Food Technology, Durban University of Technology, PO Box 1334, Durban 4000, South Africa.

Abstract

Taro [Colocasia esculenta (L.) Schott] has the potential to address food and nutrition insecurity in sub-Saharan Africa. However, the nutrient content of taro is yet to be fully elucidated. The objective of this study was to evaluate mineral element content as a proxy for nutritional value of different taro genotypes. The study evaluated 14 taro accessions at Roodeplaat and Umbumbulu in South Africa based on their calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorous (P) and zinc (Zn) content. The accessions were planted in a randomized complete block design, replicated three times under field conditions. The mineral element content varied significantly (p < 0.05) among the genotypes. Genotypes Amad7-2, Umbu8 and Amad101 exhibited high Ca (≥432 mg kg^-1), Fe (≥32 mg kg^-1) and Mg (≥229 mg kg^-1) across the locations. The first principal component (PC) accounted for 33.7% of the variation and was strongly associated with Zn (r = 0.94, p < 0.001) and P (r = 0.89, p < 0.001). The second PC explained 29.7% of the variation and was associated with Na (r = 0.83, p < 0.001), Mg (r = 0.76, p < 0.001) and K (r = 0.55, p < 0.05). Fe and Mn contributed below the 12.5% threshold to the PCs and were considered as less discriminatory among the accessions. The negative correlations among some of the mineral elements would be a challenge for selection and breeding of nutritious taro accessions. This information is essential to select superior local accessions based on their mineral element content for developing breeding populations and lines for improving nutrition quality among poor households in sub-Saharan Africa.

Keywords: Food security; Minerals; Multi-environment; Multivariate analysis; Nutrition; Selection; Variation.