Abstract:

To study the approaches for maize yield increase, this paper has analyzed the change and development of maize production techniques in the past 5 decades and more in China from the perspectives of main measures, technical characteristics and mechanisms for per unit area yield increase. The results showed that maize yield per unit area in China increased by 4 205.1 kg or 437.3% from 1949 to 2007, with annual growth rate of 85.84 kg?hm-2, and the total yield increased from 12.418 million tons to 152.30 million tons, an increase of 12.3 times, of which 68.4% was contributed by yield increase per unit area and 31.6% by planting area expansion. Total yield increase was mainly relied on yield increase per unit area. Maize production techniques have been developed in breeding and planting. Maize breeding and popularization experienced four stages: selection and popularization of open-pollinated varieties, intervarietal hybrid, double-cross hybrid and triple-cross hybrid, single-cross hybrid. After heterosis was extensively used, disease-resistant gene selection, plant type improvement, green-keeping and late-maturing have become main development trends of breeding techniques to increase maize yield potential. In future, the development trend of maize varieties is close planting, adversity resistance, high adaptability, high yield and adaptability for mechanized operation. Planting techniques has shifted from popularization of individual techniques and improvement of farmland conditions to technical integration and modeled cultivation. In future, varieties suitable for high-density and with high adversity resistance and simplified high-yield and high-effective planting techniques with mechanization as carrier will be the development trend. With constant increase of planting density, the mechanisms for maize yield increase have shifted from yield increase per plant to improvement of plant types, colony enlargement, green keeping, late maturing and increase of colony yield via extension of photosynthesis and filling time, improvement of colony uniformity, and high effective carbohydrate production and translocation after florescence. In addition, higher requirements have been set for lodging resistance, disease resistance and adaptability of colony. Based on the above analysis, it is proposed the main technical requirements and measures for maize yield increase in the near future in China.

Key words: maize, yield, yield increase factor, development trend