Unravelling the impact of soil types on zinc, iron, and selenium concentrations in grains and straw of wheat/Amblyopyrum muticum and wheat/Triticum urartu doubled haploid lines

The concentration of mineral nutrients in plants is associated with bioavailabilities of soil mineral nutrients, which are regulated by various soil physio-chemical properties. A pot experiment was conducted to investigate the effects of soil type on grain and straw zinc (Zn), iron (Fe) and selenium (Se) concentrations of wheat/Amblyopyrum muticum and wheat/Triticum urartu doubled haploid lines. A set of 42 treatments in a factorial combination with 21 genotypes and two soil types collected from Ngabu and Chitedze Research Stations in Malawi was laid in a randomised complete block design (RCBD) in three replicates. Pre-experiment soil Zn and Fe were extracted using DTPA extraction method followed by analysis with inductively coupled plasma-mass spectrometry (ICP-MS). Aqua-regia hotplate acid digestion was used to extract soil Se and analysis was done using ICPM-MS. Grain and straw samples were digested using nitric acid digestion (HNO3) and analysed using ICP-MS. Soil analysis results showed that the two soils had the same textural class (Sandy clay loam), but different mineral concentrations, pH levels and percentage organic matter. Analysis of variance revealed a ~two-fold higher Zn concentration in grains grown in low pH, high Zn soils (Chitedze soils) compared to grains grown in high pH, low Zn soils (Ngabu soils). Variation in grain Zn concentration was associated with the genotypes (p = 0002), soil type (p = <0.0001), and their interaction (p = 0.035). Grain Fe was 1.3-fold higher in low pH than in high pH soils, and it was influenced by genotypes (p = < 0.0001) and soil type (p = <0.0001). Grain Se was highly associated with soil type (p = <0.0001), and it was 30-fold higher in high pH than in low pH soils. Straw Zn was generally higher in plants grown in Chitedze soils than Ngabu soils, whilst straw Se was higher in plants grown in Ngabu soils than Chitedze soils. The findings demonstrate the significance of soil physio-chemical properties for mineral accumulation and distribution to plant parts, thus informing future breeding programs on important considerations on crop genetic biofortification with the three mineral elements

Preliminary Studies of the Performance of Quinoa (Chenopodium quinoa Willd.) Genotypes under Irrigated and Rainfed Conditions of Central Malawi

The goal of sustainable intensification of agriculture in Malawi has led to the evaluation of innovative, regionally novel or under-utilized crop species. Quinoa ( Chenopodium quinoa Willd.) has the potential to provide a drought tolerant, nutritious alternative to maize. We evaluated 11 diverse varieties of quinoa for their yield and agronomic performance at two locations, Bunda and Bembeke, in Malawi. The varieties originated from Ecuador, Chile and Bolivia in South America; the United States and Canada in North America; and, Denmark in Europe, and were chosen based on their variation in morphological and agronomic traits, and their potential for adaptation to the climate of Malawi. Plant height, panicle length, days to maturity, harvest index, and seed yield were recorded for each variety under irrigation at Bunda and Bembeke, and under rainfed conditions at Bunda. Plant height was significantly influenced by both genotype and environment. There were also significant differences between the two locations for panicle length whereas genotype and genotype × environment (G × E) interaction were not significantly different. Differences were found for genotype and G × E interaction for harvest index. Notably, differences for genotype, environment and G × E were found for grain yield. Seed yield was higher at Bunda (237–3019 kg/ha) than Bembeke (62–692 kg/ha) under irrigated conditions. The highest yielding genotype at Bunda was Titicaca (3019 kg/ha) whereas Multi-Hued was the highest (692 kg/ha) at Bembeke. Strong positive correlations between seed yield and (1) plant height ( r = 0.74), (2) days to maturity ( r = 0.76), and (3) biomass ( r = 0.87) were found under irrigated conditions. The rainfed evaluations at Bunda revealed significant differences in seed yield, plant biomass, and seed size among the genotypes. The highest yielding genotype was Black Seeded (2050 kg/ha) followed by Multi-Hued (1603 kg/ha) and Bio-Bio (1446 kg/ha). Ecuadorian (257 kg/ha) was the lowest yielding genotype. In general the seed yields of the genotypes were lower under rainfed conditions than under irrigated conditions at Bunda. The results also highlight the need to continue evaluating a diverse number of cultivars to select for genotypes adapted to specific agro-ecological areas and across seasons in Malawi

Unravelling the impact of soil types on zinc, iron, and selenium concentrations in grains and straw of wheat/Amblyopyrum muticum and wheat/Triticum urartu doubled haploid lines

The concentration of mineral nutrients in plants is associated with bioavailabilities of soil mineral nutrients, which are regulated by various soil physio-chemical properties. A pot experiment was conducted to investigate the effects of soil type on grain and straw zinc (Zn), iron (Fe) and selenium (Se) concentrations of wheat/Amblyopyrum muticum and wheat/Triticum urartu doubled haploid lines. A set of 42 treatments in a factorial combination with 21 genotypes and two soil types collected from Ngabu and Chitedze Research Stations in Malawi was laid in a randomised complete block design (RCBD) in three replicates. Pre-experiment soil Zn and Fe were extracted using DTPA extraction method followed by analysis with inductively coupled plasma-mass spectrometry (ICP-MS). Aqua-regia hotplate acid digestion was used to extract soil Se and analysis was done using ICPM-MS. Grain and straw samples were digested using nitric acid digestion (HNO3) and analysed using ICP-MS. Soil analysis results showed that the two soils had the same textural class (Sandy clay loam), but different mineral concentrations, pH levels and percentage organic matter. Analysis of variance revealed a ~two-fold higher Zn concentration in grains grown in low pH, high Zn soils (Chitedze soils) compared to grains grown in high pH, low Zn soils (Ngabu soils). Variation in grain Zn concentration was associated with the genotypes (p = 0002), soil type (p = <0.0001), and their interaction (p = 0.035). Grain Fe was 1.3-fold higher in low pH than in high pH soils, and it was influenced by genotypes (p = < 0.0001) and soil type (p = <0.0001). Grain Se was highly associated with soil type (p = <0.0001), and it was 30-fold higher in high pH than in low pH soils. Straw Zn was generally higher in plants grown in Chitedze soils than Ngabu soils, whilst straw Se was higher in plants grown in Ngabu soils than Chitedze soils. The findings demonstrate the significance of soil physio-chemical properties for mineral accumulation and distribution to plant parts, thus informing future breeding programs on important considerations on crop genetic biofortification with the three mineral elements