Location: Sustainable Perennial Crops LaboratoryTitle: Growth and nutritional responses of wild and domesticated cacao genotypes to soil Cd stress
|GARDINI, G - Tropical Crop Institute (ICT)|
|AREVALO-HERNANDEZ, C - Tropical Crop Institute (ICT)|
|BARRAZA, F - Tropical Crop Institute (ICT)|
|FARFAN, A - Tropical Crop Institute (ICT)|
|HE, Z - Indian River State College|
Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2020
Publication Date: 12/11/2020
Citation: Gardini, G.E., Arevalo-Hernandez, C.C., Barraza, F., Farfan, A., He, Z.L., Baligar, V.C. 2020. Growth and nutritional responses of wild and domesticated cacao genotypes to soil Cd stress. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2020.144021.
Interpretive Summary: Cacao beans from tropical America contain high levels of cadmium and such accumulation of cadmium is lowering the seed quality and affecting their value in international trade. Cadmium is also toxic to plant growth and its mineral nutrition. Selection and planting of cacao genotypes that take up low cadmium have advantage in reducing cadmium accumulations by cacao beans and improving the growth and development of cacao. This research showed the existence of genotypic variation among cacao genotypes in accumulation of cadmium. This information will be useful to plant breeders to breed non cadmium, accumulating cacao cultivars thereby reduce cadmium in cacao beans. Farmers can use such low cadmium accumulating cultivars in soil area where cadmium toxicity is an issue.
Technical Abstract: Cadmium (Cd), a toxic and non-essential metal, is easily accumulated in cacao tissues, representing a risk for cacao exportation, and consequently affecting the economic well-being of the resource poor small-producers in Latin America. A greenhouse experiment was conducted with 53 wild and domesticated cacao genotypes to determine their response to Cd in terms of growth and nutritional status. Cacao seedlings were grown for 6 months in an acidic soil with or without of added Cd. Total concentration of macro (Ca, K, Mg, N and P) and micronutrients (B, Cu, Fe, Mn and Zn) as well as Cd, nutrient uptake and nutrient uptake efficiency were measured in shoots along with growth (biometric) parameters after harvest. The results revealed that even if there was a wide range of Cd contents (3±0.1 to 853±52 mg plant-1), there was a reduction in the concentration of essential nutrients but remain similar (within the error) to the control. In the case of growth parameters, effects were diverse leading either to an increase or reduction of them compared to the average total values and across all genotypes. Thus, different growth responses to Cd are related to a genotype effect. A total of 10 cacao genotypes (AYP-22, UGU-126, ICT-1026, ICT-1087, ICT-1189, ICT-1292, PH-17, CCN-51, ICS-39 and TSH-565) are proposed here as Cd-safe based on its lower Cd- accumulation capacity and therefore potentially useful for breeding techniques.