By: Prof. R K Yadav (Deptt of Genetics and Plant Breeding C.S. Azad Univ. of Agril. & Tech. Kanpur & Sr. Associate Editor-ICN Group) and Dr. Shweta (Asstt. Professor)
KANPUR: Maize (Zea mays), known in some English speaking countries as corn. In India, maize ranks 3rd after rice and wheat. Maize grown throughout the country ranging from Kashmir to Kanyakumari. Improving nutritional quality of agricultural crops is a noble goal. Improving nutritional quality in cereal crops is particularly important as the benefits can easily spread to hundreds of millions of people in a most rapid and effective manner without changing the traditional food habits.
About maize, scientist had demonstrated several decades ago that maize protein is nutritionally deficient because of the limiting quantities of two essential amino acids lysine and tryptophan. However, it was a long wait till some high lysine mutants of maize such as Opaque-2 and Floury–2 were discovered.
The discovery of the biochemical effects of these two mutants paved the way for genetic manipulation in breeding to improve the nutritional quality of maize endosperm protein.
Introduction of mutant genes into normal maize brings two folds increase in the levels of lysine and tryptophan. Lysine deficient zein or prolamine fraction is reduced dramatically by about 50 per cent while other fractions albumins, globulines and glutelins rich in lysine show a marked increase.
The nutritional superiority of QPM over normal maize has been well established. Amongst cereal QPM posses the highest nutritive value which is almost equivalent to milk protein casein. QPM can become a boon to young children, especially to those suffering from protein malnutrition.
Research suggests that QPM can help reduce protein deficiencies, particularly in young children where maize dominates in the diets. In QPM varieties, leucine: isoleucine ratio was improved and become better balanced which interm considered beneficial as it helps to liberate more tryptophan for more niacin biosynthesis, thus helping to combat pellagra.
The other nutritional benefits of QPM include higher calcium and carbohydrates and carotene utilization. Another important application of QPM is as animal feed, especially for mono-gastric animals such as pigs and poultry, as it results in improved growth.
Small holding farmers (who typically cannot afford balanced feeds) and commercial farmers find this extremely remunerative. Therefore, the development and adoption of improved QPM cultivars have significant potential to alleviate hunger, increase incomes and improve livelihoods.
