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Iron Toxicity

  • Objective: Iron toxicity-tolerant rice - Identify the best sources of tolerance for iron toxicity, elucidate the genetic control, and develop and test improved tolerant varieties under farmers’ fields and improved management practices.
Research progress

Inventory of existing African iron-toxicity-tolerant germplasm completed

A list of 181 accessions was compiled, including two sensitive checks. The material comprises accessions from different institutes (AfricaRice, IRRI, CIAT, and NARES). Six advanced bulk populations for evaluating iron-toxicity tolerance were dispatched from IRRI to AfricaRice and many segregating populations were sent to Nigeria (IRRI-Africa).

Participatory varietal selection conducted for at least 10 iron-toxicity-tolerant lines at key sites in four SSA countries (Nigeria, Guinea, Burkina Faso, Benin) by AfricaRice

Two PVS trials were established at Banfora (Burkina Faso) and Edozighi (Nigeria) with a set of 181 entries. Farmers’ field days were organized at both sites, involving 60 farmers, with women in the majority, at Banfora and 43 farmers, almost exclusively men, attending the field day at Edozighi. The rating sheets collected at both sites have been compiled on farmers’ choices and perceptions. 

Phenotyping for iron-toxicity screening at AfricaRice refined

Three approaches are being used to screen for iron-toxicity tolerance—field trials, pot trials, and hydroponics trials. The pot-trial protocol uses plastic pots filled with sand supplemented with Fe2+ as FeSO4. Optimal fertilizer (100 kg ha–1 N, 50–100 kg ha–1 P, and 60–100 kg ha–1 K) will be applied to allow normal growth of rice plants in order to avoid nutrient disorders. Forty genotypes were screened with this protocol using two concentrations of Fe2+ (300 and 900 ppm). The first symptoms observed were a reduction in plant height and tillering, whereas leaf bronzing appeared later. In parallel, 180 genotypes were screened in the field at hotspots in Edozighi (Nigeria) and in Banfora (Burkina Faso). 
Iron-toxicity tolerance was scored and grain yield will be determined as well as morpho-physiological traits. Hydroponic screening is being planned in collaboration with IRRI and the University of Hohenheim, Germany. The same 180 accessions will be screened for leaf bronzing score (LBS) and other morpho-physiological traits will be measured at IRRI.