Aflatoxins are carcinogenic secondary metabolites produced predominantly by the fungi Aspergillus flavus and parasiticus. The toxin contaminate maize grains and threatens human food safety. Survey in Ghana revealed aflatoxin contamination of maize in excess of 941 ppb which is way beyond WHO and USA approved limits of 15 ppb and 20 ppb respectively. Host plant resistance is considered as the best strategy for reducing aflatoxins. This study was designed to (1) identify and select suitable maize lines that combine aflatoxin accumulation resistance and good agronomic traits under tropical conditions and (2) assess the genetic diversity among the exotic and locally adapted maize genotypes using significant morphological traits. Thirty-six maize genotypes, 19 from Mississippi State University, USA and 17 locally adapted genotypes in Ghana were evaluated for aflatoxin accumulation resistance and good agronomic characteristics across six contrasting environments using a 6x6 lattice design with three replicates. Five plants each per genotype were inoculated with a local strain of Aspergillus flavus inoculum at a concentration of 9 x 107/3.4 ml, two weeks after 50% mid silking. Total aflatoxin in the kernels were determined at harvest using HPLC method. Statistical analysis for agronomic traits and aflatoxin levels were performed using PROC GLM procedure implemented in SAS. The result indicated that genotype by environment interaction was significant (p < 0.05) for aflatoxin accumulation resistance and many other agronomic traits. Five genotypes (MP715, NC298, MP705, MP719, CML287 and TZEEI- 24) consistently displayed stable resistance across the environments and may serve as suitable candidates for developing aflatoxin resistant hybrids. Cluster analysis showed two distinct groups (locally adapted and exotic genotypes), an indication of re-cycled alleles per region. Broad sense heritability estimates for grain yield and aflatoxin accumulation resistance were moderately high, which could permit transfer of traits during hybrid development.
Part of the book: Cereal Grains
The success of the UN Sustainable Development Goals in reducing hunger and poverty is limited by crop losses. Globally, plant pests and diseases account for 40% yield losses which threatens food and nutrition security, livelihoods of citizenry and erode the resources of local and national economies. Phytophthora diseases are among the most important diseases in sub-Saharan Africa which result in severe socio-economic consequences. Roots and tubers and cash commodity crops are important staples and foreign exchange earner crops in Ghana which are significantly challenged by the incidence and severity of Phytophthora diseases. To ensure food availability, safeguard the local financial ecosystem and protect the environment, innovative and sound management practices are needed and this chapter reviews the different Phytophthora diseases on crops; more specifically with (cocoa and taro as case studies), the consequences and available management options that can be applied to manage the disease situation in Ghana.
Part of the book: Agro-Economic Risks of Phytophthora and an Effective Biocontrol Approach