Audrey Sebolt
(Michigan State University)
EDUCATION
The role of public wheat breeding in reducing food insecurity in South Africa
Although classified as an upper middle-income country, food insecurity is still a concern throughout South Africa, as was evident in 2014–2015 when a drought left 22% of households food insecure. Further, a range of domestic and international factors make the local currency unstable, leaving South Africa exposed to risk in global wheat and exchange rate markets and increasing its food insecurity vulnerability. As such, agricultural research in South Africa is needed specifically in plant breeding to increase yields and help mitigate future food insecurity. To foster scientific innovation for food security, the South African government funds the Agricultural Research Council (ARC), which conducts holistic research on wheat and other crops. This study estimates the proportions of increases in yield of ARC’s wheat cultivars, which are attributable solely to genetic improvements. In total, 25,690 yield observations from 125 countrywide test plots from 1998 to 2014 were utilized to estimate the proportions of yield increases attributable to the ARC. We found that South African farmers who adopted the ARC’s wheat varieties experienced an annual yield gain of 0.75%, 0.30%, and 0.093% in winter, facultative, and irrigated spring wheat types, respectively. Using observed area sown to ARC varieties, we estimated that wheat producers gained $106.45 million (2016 USD) during 1992–2015 via the adoption of ARC varieties. We estimated that every dollar invested in the ARC wheat breeding program generated a return of $5.10. Assuming the South African per capita wheat consumption is 60.9 kg/year, our results suggest that the ARC breeding program provided an average of 253,318 additional wheat rations from 1992–2015. Further, the net surplus (consumer plus producer) from the ARC breeding program was estimated at 42.64 million 2016 USD from 1992–2015.Public breeding programs, especially those focused on wheat and other staple foods, mustcontinue if South Africa is to meet growing global food demand, decrease present globalfood insecurity, and maintain the genetic enhancements that directly enhances yield andbenefits low-income consumers
By:
Audrey Sebolt
EDUCATION
Evolution and Phylogenetic Diversity of Yam Species (Dioscorea spp.): Implication for Conservation a
Yams (Dioscorea spp.) consist of approximately 600 species. Presently, these species are threatened by genetic erosion due to many factors such as pest attacks and farming practices. In parallel, complex taxonomic boundaries in this genus makes it more challenging to properly address the genetic diversity of yam and manage its germplasm. As a first step toward evaluating and preserving the genetic diversity yam species, we use a phylogenetic diversity (PD) approach that has the advantage to investigate phylogenetic relationships and test hypotheses of species monophyly while alleviating to the problem of ploidy variation within and among species. The Bayesian phylogenetic analysis of 62 accessions from 7 species from three regions of Cameroon showed that most Dioscorea sections were monophyletic, but species within sections were generally non-monophyletic. The wild species D. praehensilis and cultivated D. cayenensis were the species with the highest PD. At the opposite, D. esculenta has a low PD and future studies should focus on this species to properly address its conservation status. We also show that wild species show a stronger genetic structure than cultivated species, which potentially reflects the management of the yam germplasm by farmers. These findings show that phylogenetic diversity is a promising approach for an initial investigation of genetic diversity in a crop consisting of closely related species.
By:
Audrey Sebolt
EDUCATION
Phenotypic divergence between the cultivated apple (Malus domestica) and its primary wild progenitor
An understanding of the relationship between the cultivated apple (Malus domestica) and its primary wild progenitor species (M. sieversii) not only provides an understanding of how apples have been improved in the past, but may be useful for apple improvement in the future. We measured 10 phenotypes in over 1000 unique apple accessions belonging to M. domestica and M. sieversii from Canada’s Apple Biodiversity Collection. Using principal components analysis (PCA), we determined that M. domestica and M. sieversii differ significantly in phenotypic space and are nearly completely distinguishable as two separate groups. We found that M. domestica had a shorter juvenile phase than M. sieversii and that cultivated trees produced flowers and ripe fruit later than their wild progenitors. Cultivated apples were also 3.6 times heavier, 43% less acidic, and had 68% less phenolic content than wild apples. Using historical records, we found that apple breeding over the past 200 years has resulted in a trend towards apples that have higher soluble solids, are less bitter, and soften less during storage. Our results quantify the significant changes in phenotype that have taken place since apple domestication, and provide evidence that apple breeding has led to continued phenotypic divergence of the cultivated apple from its wild progenitor species.
By:
Audrey Sebolt