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This dissertation consists of two essays. The first essay studies the economic impact of improved bean varieties (IVs) in Costa Rica, El Salvador, Honduras, Nicaragua, and Ecuador. In these countries, the National Agricultural Research Systems (NARS), in collaboration with private and public institutions, have actively generated and promoted IVs over the past 20 years. There are two types of yield gains derived from the use of IVs: Type I gains in areas where IVs replace traditional varieties, and Type II gains in areas where new IVs replace old IVs. Previous studies have only estimated Type I benefits in Honduras and northern Ecuador. This study estimated the Type II yield gains associated with varietal development of small red and red mottled bean varieties over time in Central America, Honduras, and northern Ecuador, using experimental yield data. Further, it provided estimates of current total adoption rates of IVs in each country, using bean expert opinions. The economic impact of bean IVs was estimated by combining the Type I and Type II yield gains. The results suggest that the Type II yield gains from small red varieties averaged 0.49% per year for Central American countries and 0.56% per year for Honduras. Similarly, the Type II yield gains from red mottled varieties averaged 1.68% per year for Ecuador. Breeders estimated that adoption rates for 2010 ranged from 46% in Honduras to 82% in Nicaragua. Amadeus 77 was the most widely adopted small red IV in Central America and accounted for an estimated 49.7% of the total bean area. Similarly, Portilla, the most widely planted red mottled IV in northern Ecuador and accounted for an estimated 43% of the red mottled bean area in northern Ecuador. Ex post benefit/cost analysis for the period 1991–2015 indicate that returns to investments in bean research have been negative in Costa Rica and positive in all other countries, with a regional net present value of $358 million and a regional IRR of 32%. The surplus per hectare per year was estimated at $74/ha/yr in the region.
The second essay studies the factors affecting farmers' marketing decisions in the rural highlands of Angola, focusing on potatoes, beans, and onions. This essay uses single equation ordinary least squares regressions for analysis of factors affecting production of potatoes, beans, and onions in the central highlands of Angola. Furthermore, it implements double hurdle (DH) regressions to study the factors associated with farmers' marketing decisions among potato, bean and onion growers, focusing on gender of the household head, asset ownership, and transaction costs, while controlling for potentially endogenous variables. The DH regression results suggest that the factors associated with marketing decisions depend on the crop analyzed and on whether marketing decisions are analyzed conditionally (i.e., probability of selling and, conditional on selling, quantity sold) or unconditionally (i.e., unconditional quantity sold). The results also suggest that boosting sales would be a challenge for the government of Angola, donors, and organizations working with farmers in this region since, due to Angola's strong currency, overcoming the limiting factors found in this study may require large financial and human resources.