Abstract:From 1996 to 1998, several experiments and mass cultivation of winter maize are carried out in Caoba, Mengzi County, Yunnan. High yield were successily obtained in 3 years. The main reasons are as follows: 1. The growth period of winter maize is obviously longer than others. 2. The LAI development of winter maize match well with the resource of light and heat in Caoba. This is the basis of high yielding of winter maize. 3. At mid-filling stage, the mean light flux density (LFD) per day is 1391.8μE.m-2.s-1. The plants intercept and capture 87.6% of the total LFD. Enough light at basal layer can delay the leaf senescence, which provides better conditions for the total dry matter production of grain at filling period. 4. The amount of dry matter production for winter maize after silking account for 72.1 % of the total dry matter. This is advantageous to grain production. 5. Dry matter 12.78% produced at filling stage has remained in the vegetative organs, indicates that the source capacity is a limiting factor of obtaining a high yield. Enlarging the source capacity may further increase the yield of winter maize.