Intraspecific plant variation mediates the effect of crop diversity
under drought stress
Abstract
Increasing interspecific and intraspecific diversity in agricultural
systems provides promising solutions for sustainably increasing crop
yield. Most research so far has focused on understanding plant–plant
interactions to develop productive crop mixtures. The role of specific
plant varieties in mediating such interactions is relatively
understudied. Common bean is a widely cultivated crop in North
Macedonia, usually grown in monocultures. Drought is one of the main
yield limiting factors for beans in the country. Our study is part of a
project that aims to improve bean production in North Macedonia by using
measures such as intercropping. We first conducted a greenhouse
experiment to determine drought tolerant bean varieties. The chosen
varieties were further grown in a second greenhouse experiment with
additional crop species in different species and cultivar mixtures. The
aim of our study was to select plant/cultivar mixtures that result in
higher bean yield and that can be trialed in farmer fields in North
Macedonia. We hypothesized that the interaction of beans with the
additional crop species will be influenced by water stress and by the
identity of bean varieties. Overall, we recorded sorghum and chickpea
presence to increase bean yield and sunflower presence to reduce bean
yield, irrespective of drought stress. However, the effect of these
additional species on bean yield varied across different bean varieties.
This could partially be explained by variation in growth rate between
varieties, where the fastest growing variety recorded the highest yield
increase in crop mixtures. Our study highlights the role that crop
genetic variation can play in mediating interspecific plant
interactions. We suggest that to develop crop mixtures, it is not only
important to consider the functional traits of the interacting plant
species, but also of the different plant varieties.