This study determined the effect of hybrid breeding on cultivar diversity in rice (Oryza sativa L.) production in China. The results showed that hybrid breeding led to increases in the Shannon index of cultivar diversity by 29–184% during the period 2011–2015 compared with the period 1986–1990 for 10 major hybrid rice-producing provinces in China. There was a significant exponential relationship between the Shannon index of cultivar diversity and the number of hybrid cultivars and the total number of cultivars across the 10 provinces and the...
