Chemically and Microbially Mediated Kinship Strategies in Rice Cultivar Mixtures

Improved yields can occur in closely related cultivar mixtures. Despite increasing knowledge of the benefits of neighbour-relatedness in intraspecific interactions, little is known about chemically and microbially mediated kinship responses in cultivar mixtures. Using a series of field and controlled experiments that used two sets of rice cultivars of varying genetic relatedness, we demonstrated that increased yield in rice cultivar mixtures was mediated by a root signaling chemical and soil microbes in a relatedness-dependent manner. Focal rice cultivars could discriminate closely from distantly related cultivars responded by altering root behavior, biomass allocation, and flowering time, improving grain yield. Relatedness discrimination was accompanied by an alteration in root signaling (-)-loliolide and, subsequently, the soil microbial community. Furthermore, (-)-loliolide directly modified soil microbes that were related to flowering time and seed biomass. Therefore, neighbor relatedness shapes soil microbial communities, generating kinship effects in rice cultivar mixtures. In particular, root signaling (-)-loliolide levels and soil microbial responses generated improvement of grain yield in closely related rice cultivar mixtures. The findings not only yield critical insights into plant-neighbor and plant-soil interactions but also raise an intriguing possibility to increase crop production by manipulating kinship in cultivar mixtures.