This paper investigates the relationship between adoption of modern rice varieties and rice varietal diversity
on household farms in Bangladesh. As shown in previous studies, adoption of modern varieties depends on
agroecological- and input-related factors, including the availability and use of irrigation facilities, such as tubewells.
Having irrigation affects the diversity index significantly and positively, which could be due to the diffusion of more
modern varieties (MVs) in areas where irrigation is available and accessible.
Farmers who acquire seeds from informal sources—i.e. from their own farm or neighboring farmers—are more
likely to adopt MVs. This is because there is neither a formal seed market nor a formal seed distribution system that
farmers can rely on for their seeds. Almost 70 percent of the sampled farmers grow more than one variety per season.
The number of varieties planted is higher in the wet season (aman) than in the dry season (boro): in the wet season,
almost 90 percent of the sampled farmers grew more than one variety. Varietal diversity is higher in unfavorable areas,
such as saline-affected areas. Farmers with larger landholdings are more likely to have higher levels of on-farm varietal
diversity. These factors held constant, farmers who have adopted MVs are less likely to have higher levels of on-farm
varietal diversity.
This empirical evidence is consistent with the hypothesis that cultivating MVs reduces rice varietal diversity, as MV
adoption reduces production risk and increases income because of higher yields. Farmers value these traits, which
should be considered when breeders develop new varieties. Although farmers’ education was not significant in MV
adoption, education is a significant determinant in rice varietal diversity in accessing information or knowledge about
the traits of MVs. Educated farmers have the ability to decide which MV to grow among a wide range of choices.