An increase in the total grain and biomass yields and photosynthetic rates of plants grown at high densities is achieved by novel methods of defoliating the primary-source leaf of a majority of such plants. In particular the methods provide for increased grain and biomass yields, including for example, increased average kernel mass for maize plants, and photosynthetic rates through the timely removal of the primary-source leaf of a majority of the plants grown at high densities. This invention also relates to seeds obtained by using the disclosed methods.
