Multilocation dataset on seed Fe and Zn contents of bean (Phaseolus vulgaris L.) genotypes grown in Tanzania

There are over a hundred genotypes of Phaseolus vulgaris L. grown and consumed in Tanzania. Currently, identification of bean genotypes containing high seed iron and zinc contents has been the focus globally for common bean iron and zinc biofortification. Diversity in seed iron and zinc contents were investigated in 99 bean genotypes grown in Tanzania to identify high seed iron and zinc-containing genotypes for use in iron and zinc biofortification. Flour obtained by grinding seeds of each bean genotypes was used in the determination of iron and zinc concentrations. Data were subjected to analysis of variance (ANOVA) to determine significant differences among common bean genotypes in terms of seed iron and zinc contents. Additive main effects and multiplicative interaction (AMMI) and genotype plus genotype by environment interaction (GGE) were conducted to determine stability and adaptation across sites (TARI-Selian, SUA, and TARI-Uyole) of bean genotypes in terms of seed iron and zinc contents. Data in this data article show that some landraces had high seed iron and zinc contents compared to release varieties thus can be used for iron and zinc genetic biofortification in common beans breeding programs. For more explanation of the data presented in this data article, please follow the related research article “Environmental and genotypes influence on seed iron and zinc levels of landraces and improved varieties of common bean (Phaseolus vulgaris L.) in Tanzania” [1]


a b s t r a c t
There are over a hundred genotypes of Phaseolus vulgaris L. grown and consumed in Tanzania. Currently, identification of bean genotypes containing high seed iron and zinc contents has been the focus globally for common bean iron and zinc biofortification. Diversity in seed iron and zinc contents were investigated in 99 bean genotypes grown in Tanzania to identify high seed iron and zinc-containing genotypes for use in iron and zinc biofortification. Flour obtained by grinding seeds of each bean genotypes was used in the determination of iron and zinc concentrations. Data were subjected to analysis of variance (ANOVA) to determine significant differences among common bean genotypes in terms of seed iron and zinc contents. Additive main effects and multiplicative interaction (AMMI) and genotype plus genotype by environment interaction (GGE) were conducted to determine stability and adaptation across sites (TARI-Selian, SUA, and TARI-Uyole) of bean genotypes in terms of seed iron and zinc contents. Data in this data article show that some landraces had high seed iron and zinc contents compared to release varieties thus can be used for iron and zinc genetic biofortification in common beans breeding programs. For more explanation of the data presented in this data article, please follow the related research article "Environmental and genotypes influence on seed iron and zinc levels of landraces and improved varieties of common bean ( Phaseolus vulgaris L.) in Tanzania " [1] © 2020 The Author(s The concentrations of iron and zinc in common bean seeds, were obtained after grinding into flour air dried seeds of each harvested genotype Description of data collection The data on seed iron and zinc concentration were obtained by atomic absorption spectrophotometer, after digestion of ground samples by dry ashing Data

Value of the data
• This data set provides additional information on the effect of different agro-ecological conditions on seed iron and zinc contents of common bean genotypes • The dataset in the article provides information to common bean researchers, nutritionist and consumers on iron and zinc nutritional values among common beans genotypes grown in Tanzania • The data given are useful in genetic study of seed iron and zinc and plant breeding programs particularly iron and zinc biofortification

Data Description
Common beans have relatively higher seed iron and zinc contents compared to most other staple food crops particularly cereals, thus a good source of nutritional iron and zinc to human beings particularly in developing countries [1 , 2] . In human body, the highest percentage of iron is used for hemoglobin to carry oxygen around the body and its deficiency retards the growth and cognitive ability of children, lowers resistance to infectious diseases, and reduces the physical work capacity and productivity of adults [3 , 4] . Zinc plays an important role in the human body's immune system, cell division, cell growth, wound healing, carbohydrate metabolism, reproduction and smell and taste senses [5 , 6] . Zinc deficiency leads to reduced body immune response, slow wound healing, infertility and reduce growth and development [7 , 8] .
Data set in this article consist of information on seed iron and zinc concentration of 99 common bean genotypes that were planted and harvested from three different bean growing location in Tanzania. Data presented in this article consists of four figures and three tables. Table 1 shows variation in seed iron contents among 79 common bean genotypes, whereas Table 2 presents the variation in seed zinc among 79 common bean genotypes in the three experimental sites, the remaining genotypes seed iron and zinc contents have been published [1] . Mean seed iron and zinc contents, AMMI stability value (ASV) and genotype stability index (GSI) of common bean genotypes across sites are presented in Table 3 . In Fig. 2 , the mid  Means followed by the same letter are not significantly difference, while those followed by different letters had significant difference at the 5% level by Duncan new range multiple tests (DNRMT). LSD = least significance difference, and CV = coefficient of variation horizontal dotted line exhibited the interaction (PCA1) of zero, and common bean genotypes closer to the line were less involved in genotype by environment interaction. The vertical mid line represents seed iron grand mean, genotypes placed in the right hand side, had higher seed iron compared to those in the left hand side. The most stable and high seed iron-contentaining genotypes included G11 (Chumba neroza), G17 (KAB o6F2-8-35), G88 (Urafiki), G82 (SMC 18), G77 (Selian 94), G35 (Kikobe) and G48 (Malirahinda), as they were found closer to PC1 zero and placed far towards the direction of high seed iron content. Fig. 3 . GGE biplot, displaying how the experimental sites differ in discriminating ability and representativeness on common bean genotypes ranking in terms of seed iron contents. The length of the experimental site vector from the biplot origin shows the discriminating ability of the site on superior genotypes for seed iron contents. The small angle between the experimental site and average environmental axis indicates representativeness of the site for the experiment. E3 (SUA), with small angle to the average environmental axis (AEA), was observed to be more representative site compared to the rest. E1 (TARI-Selian) with longer vector from the biplot origin had good discriminating ability compared to other sites. E1 and E3 both fall into the third concentric circle of the ideal environment and closer to average environment. Thus, E1 had good discriminating ability and representativeness, and therefore an ideal site for evaluating common bean genotypes for seed iron contents.

Plant materials
A total of 100 common beans including 59 landraces, 32 released varieties and 9 lines grown in Tanzania were used in this study. Seeds of these varieties were collected from four major bean growing Regions in Tanzania; namely Mbeya, Kagera, Arusha and Morogoro. Furthermore, seeds  Means followed by the same letter are not significantly difference, while those followed by different letters had significant difference at the 5% level by Duncan new range multiple tests (DNRMT). LSD = least significance difference, and CV = coefficient of variation  Table 3 Common bean genotypes mean performance on seed iron and zinc contents ranked based on AMMI stability value (ASV) and genotype stability index (GSI).

Experimental Design and Planting
The Field experiment was conducted in three sites, Sokoine University of Agriculture (SUA) and Tanzania Agricultural Research Institute -Uyole station and Selian station ( Fig. 1 ). A hundred common bean genotypes at each experimental site were planted using alpha lattice arrangement. The experiment was replicated 3 times at each experimental site, with each replicate having 5 blocks of 20 plots. Each common bean genotype was planted at 50 × 10 centimeters in two rows of 1.5 meter long and each planting hill was planted with one seed. First planting was done at TARI-Uyole station on 20 th March, 2018 and harvested on 9 th July, 2018. This was followed by planting at TARI-Selian on 30 th March, 2018 and harvested on 25 th July, 2018. Planting at SUA was done on 1 st May, 2018 and harvested on 2 nd August, 2018. Among the planted 100 common bean genotypes, one genotype, failed to germinate in all the three experimental sites and thus 99 genotypes were harvested. The failed germination may be due to overstay from where it was collected.

Data Collection
At physiological maturity, pods from each common bean plot were harvested separately, shelled, seeds air dried and put into separate paper bags. Five grams of each air dried common bean genotype were randomly selected and sent to the laboratory for iron and zinc content analyses. Cyclotec 1093 sample mill was used to ground seed sample into fine flour. Atomic absorption spectrophotometer (AAS) method was used to determine seed iron and zinc contents [9] . A sample of 0.5 g dry and ground common bean seeds from each genotype was weighed and put into porcelain crucibles. The samples in porcelain crucibles were placed into furnace. The samples were heated into ashes at the temperature of 550 °C for 5 hours. After 5 hours the furnace was turned off allowing sample ashes to cool. The cooled ashes were dissolved into 6 N HCl and thoroughly mixed. After 10 minutes the mixtures were made up to 50 mL by addition of distilled water. The solutions were filtered using whatman No. 42 filter paper. By using AAS, the filtrates from common bean samples were used to determine absorbance of each common bean genotype at wavelength of 248.3 and 213.9 nm for iron and zinc respectively, which in turn was calculated into concentrations using the following formula.

Data Analysis
The calculated concentrations of iron and zinc for each common bean genotypes from individual sites were submitted to Analysis of Variance (ANOVA) using GenStat 15 th edition statistical software (VSN International), so as to determine significant differences among varieties for the collected variable data. Genotypes seed iron and zinc means were separated using the Duncan's new multiple range test (DNMRT) method at 5% level of probability.
Additive main effects and multiplicative interaction (AMMI) model using GenStat 15 th edition statistical software (VSN International), was used to determine the effect of genotype by environment interaction, assess adaptability and stability of the cultivated common bean genotypes across environments.
Y ge = μ + α g + β e + n λ n γ gn δ en + ρ ge (2) Where Y ge is the concentration of iron or zinc for genotype g in environment e, μ is the grand mean, μ g the mean for genotype g (over environments), and μ e the mean for environment e (over genotypes), α g = μ g -μ be the genotype deviation and β e = μ e -μ is the environment deviation, λ n the singular value for n component, γ gn be the eigenvector value for genotype g and let δ en be the eigenvector value for environment e, ρ ge is the residual term. AMMI Stability Value (ASV) was used to quantify and rank the common bean genotypes based on their yield stability [10] .
Where SSIPC 1 is the interaction principal component 1 sum of square, SSIPC 2 is the interaction principal component 2 sum of square, IPC 1 and IPC 2 are interaction principle component 1 and 2 respectively. Genotype Stability Index (GSI i ) of each common bean genotype in terms of iron and zinc was calculated based on; the rank of the ith genotype across environments based on AMMI Stability Value (RASV j ) and rank of the ith genotype based on mean iron and zinc concentration across environments (RM i ) as Genotype main effect plus genotype by-environment interaction (GGE) using Plant Breeding Tools (PBTools) version 1.4 was used to determine the discriminating ability and representativeness of the experimental sites on common bean genotypes

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.