Keshab Babu Koirala Sir, Maize production is low/stable in developing countries because of a few things (for reference mentioning only two). First, there is the meager price of the harvested product (varied from 500-1000 Rupees per Quintel in UP (a northern and rich agricultural state) India, the indicated price is not official, it is actual price what the farmers receiving by selling maize) which hardly recover the production cost and Second, there is also low demand for product because people consider it as an inferior product; however, its consumption had many health benefits. To increasing maize production, there is an urgent need to create demand for maize by promoting and informing the health benefits of consumption of maize and maize made products. Once the farmers have assured demand in the market and also don't have any fear of losing the production cost, then they will allocate more farmland for maize production and produce more maize.
Production and productivity can be increased through development and promotion of: improved maize varieties, good farm and postharveat practices. This should be accompanied with proper mechanization of the production chain, improving access to agricultural financing, improve rural infrastruture and better organization of actors. Read my paper on valuation of rice postharvest losses and mitigation strategies.
Farmers can be encouraged to practice regular soil rotation, ensure water drainage, and increase the use of automated production process by decreasing manual process. Financing farmers to ensure the above is a must.
There are many variables that could influence the productivity and profitability of Maize production in developing countries.
But I would suggest based on my research experience so far,especially, for developing country, the influence of favorable Governmental policies and subsidized mechanization can not be overemphasized.
In a system where Agricultural Marketing does not quite adopt grading and standardization;such impactive productivity and profitability would take longer to attain.