Breeding plant type for adaptation to high plant density in tropical maize-A step towards productivity enhancement

Breeding for tolerance to high plant density (HPD) stress resulted in remarkable increase in grain yield per unit area in temperate maize. In spite of improved germplasm and reasonable adoption of hybrid technology, average maize productivity in tropics is still much below the achievable potential, primarily due to natural abiotic stresses and poor management due to lack of access to key inputs. A tropical maize plant, inherently distinguished with tall stem, numerous long dropping leaves, bushy tassel, rapid postsilking leaf senescence and prone to lodging, needs to be redesigned for amenability to HPD stress. With reference to the historical outlook on plant type modifications in temperate maize for adaptation to HPD and, hence, to minimize decrease in grain yield per plant resulting from crowding stress, we delineated HPD adaptation traits, which need to be focused during selection to enhance the productivity in tropical maize, a source of food, feed and livelihood to millions of resources-poor farmers.