Agro-environmental consequences of quality protein maize (QPM) hybrid development with special emphasis of soil nitrogen management

Abstract

Maize (Zea mays L.) ranks within the top three widely cultivated and consumed crops worldwide. More than one-third of the global population at both developed and underdeveloped countries depend on maize as their primary dietary supplement. During late 1990's, quality protein maize (QPM) hybrid was developed mainly to provide higher amounts of both the amino acids lysine and tryptophan, essential for humans and monogastric animals, through conventional crop breeding system. As a result of superior hybrid nature, QPM also shows improved tolerance to different environmental conditions and grows across a wide range of agro-ecological zones. In general, QPM inbred lines develop at both winter and summer season. The phenological responses and yield performance of QPM are significantly better than that of normal maize varieties. The nitrogen (N) utilization dynamics of QPM is also very interesting. Usually, it produces higher grain yield under lower N levels. The critical value of N plays an important role in tryptophan and lysine production of QPM. Therefore, lysine and tryptophan fluctuations might act as markers to understand regulatory aspects of amino acid synthesis in QPM plants under different N levels. The present review aims to catalogue previously published works at this sphere, and plans to draw a roadmap for the future researchers.