Participatory variety selection of groundnut (Arachis hypogaea L.) in Taricha Zuriya district of Dawuro Zone, southern Ethiopia

Groundnut is a leguminous seed that contains a lot of oil and protein with high energy content. However, improved varieties were hardly evaluated based on farmers' preference criteria and their participation. Therefore, a participatory variety selection was carried out in Taricha Zuriya district in Dawuro Zone on the mother-baby approach on farmers' fields in the 2019 and 2020 main cropping seasons, aiming at evaluating the performance of groundnut varieties through farmers' participation and assessing their preference criteria. Six released groundnut varieties were tested using a randomized complete block design with four replicates at farmers' fields. The mother trial was done at one model farmer field (all four replications on one field), whereas the baby trials were done at four farmers' fields by considering farmers as replication per village. Combined analysis of variance for two years showed a highly significant (P < 0.001) to significant (P < 0.01) differences among groundnut varieties for grain yield, days to 50 % flowering, days to maturity, seeds per pod, pods per plant, 100 seed weight, except for both stand count at emergence and harvest. Among the tested varieties, BaHajidu (1805.84 kg ha^-1) was identified as the best yielding groundnut variety, followed by Bulki-01 (1805.50 kg ha^-1) and Werer-963 (1780.0 kg ha^-1), respectively, while Werer-962 variety has a lower yield (1536.30 kg ha^-1). Bulki-01 (96), BaHajidu (90), and Werer- 963 (76) obtained higher score values as preferred by farmers, whereas lower score values were observed for Manipinter variety (45). The aforementioned varieties Bulki-01, BaHajidu and Werer-963 were also preferred using selection criteria set by farmers as 1^st, 2^nd, and 3^rd in rank order respectively. Hence, based on farmers' preference values and biological data, these three groundnut varieties were recommended for pre-extension demonstration and large-scale production in Dawuro Zone and areas with similar agro-ecologies.

Genetic fingerprinting and aflatoxin production of Aspergillus section Flavi associated with groundnut in eastern Ethiopia

BACKGROUND

Aspergillus species cause aflatoxin contamination in groundnut kernels, being a health threat in agricultural products and leading to commodity rejection by domestic and international markets. Presence of Aspergillus flavus and A. parasiticus colonizing groundnut in eastern Ethiopia, as well as presence of aflatoxins have been reported, though in this region, no genetic studies have been done of these species in relation to their aflatoxin production.

RESULTS

In this study, 145 Aspergillus isolates obtained from groundnut kernels in eastern Ethiopia were genetically fingerprinted using 23 Insertion/Deletion (InDel) markers within the aflatoxin-biosynthesis gene cluster (ABC), identifying 133 ABC genotypes. Eighty-four isolates were analyzed by Ultra-Performance Liquid Chromatography (UPLC) for in vitro aflatoxin production. Analysis of genetic distances based on the approximately 85 kb-ABC by Neighbor Joining (NJ), 3D-Principal Coordinate Analysis (3D-PCoA), and Structure software, clustered the isolates into three main groups as a gradient in their aflatoxin production. Group I, contained 98% A. flavus, including L- and non-producers of sclerotia (NPS), producers of B₁ and B₂ aflatoxins, and most of them collected from the lowland-dry Babile area. Group II was a genetic admixture population of A. flavus (NPS) and A. flavus S morphotype, both low producers of aflatoxins. Group III was primarily represented by A. parasiticus and A. flavus S morphotype isolates both producers of B₁, B₂ and G₁, G₂ aflatoxins, and originated from the regions of Darolabu and Gursum. The highest in vitro producer of aflatoxin B₁ was A. flavus NPS N1436 (77.98 μg/mL), and the highest producer of aflatoxin G₁ was A. parasiticus N1348 (50.33 μg/mL), these isolates were from Gursum and Darolabu, respectively.

CONCLUSIONS

To the best of our knowledge, this is the first study that combined the use of InDel fingerprinting of the ABC and corresponding aflatoxin production capability to describe the genetic diversity of Aspergillus isolates from groundnut in eastern Ethiopia. Three InDel markers, AFLC04, AFLC08 and AFLC19, accounted for the main assignment of individuals to the three Groups; their loci corresponded to aflC (pksA), hypC, and aflW (moxY) genes, respectively. Despite InDels within the ABC being often associated to loss of aflatoxin production, the vast InDel polymorphism observed in the Aspergillus isolates did not completely impaired their aflatoxin production in vitro.

Aspergillus and aflatoxin in groundnut (Arachis hypogaea L.) and groundnut cake in Eastern Ethiopia

This study was conducted to assess major Aspergillus species and aflatoxins associated with groundnut seeds and cake in Eastern Ethiopia and evaluate growers' management practices. A total of 160 groundnut seed samples from farmers' stores and 50 groundnut cake samples from cafe and restaurants were collected. Fungal isolation was done from groundnut seed samples. Aspergillus flavus was the dominant species followed by Aspergillus parasiticus. Aflatoxin analyses of groundnut seed samples were performed using ultra performance liquid chromatography; 22.5% and 41.3% of samples were positive, with total aflatoxin concentrations of 786 and 3135 ng g^-1 from 2013/2014 and 2014/2015 samples, respectively. The level of specific aflatoxin concentration varied between 0.1 and 2526 ng g^-1 for B₂ and B₁, respectively. Among contaminated samples of groundnut cake, 68% exhibited aflatoxin concentration below 20 ng g^-1, while as high as 158 ng g^-1 aflatoxin B₁ was recorded. The study confirms high contamination of groundnut products in East Ethiopia.