Maize 11 Rice 8 Agriculture 5 Field Crops, (New March 2000) 5 Plant propagation 5 Zea mays 5 crop improvement 5 Agronomy 4 MAIZE 4 Plant Breeding and Genetics 4 Plant breeding 4 Plants 4 Crops 3 Hybrid maize 3 Oryza 3 Oryza sativa 3 RICE 3 Sorghum 3 Wheat 3 Archaeology 2 COTTON 2 Cassava 2 Corn 2 Cotton 2 Crop improvement 2 Crop yield 2 Department of Agronomy 2 Diseases of maize 2 Diseases of rice 2 Diseases of sorghum 2