PROTEIN, TRYPTOPHAN AND LYSINE CONTENTS IN QUALITY PROTIEN MAIZE, NORTH INDIA

Abstract

BACKGROUND: Maize is a major cereal crop for human nutrition world wide. Cereal proteins including maize contain about 2% lysine, which is less than one-half of the recommended concentration for human nutrition recommended by Food and Agriculture Organization in maize. Efforts for improved protein quality in maize began in mid-1960s with the discovery of mutants that produce enhanced levels of lysine and tryptophan, the two amino acids deficient in maize endosperm protein. This study was designed to determine the protein, tryptophan and lysine contents of quality protein maize grown in North India. METHODS: The protein, tryptophan and lysine contents of improved genotypes of quality protein maize and two local checks were studied between June 2005 and January 2006 on seeds of Maize grown in three localities in North agro-ecological zones of India. Protein content was determined using micro- Kjeldahl method. Data on tryptophan and lysine content was determined by using procedures described in Hernandez and Bates, Mertz et al., and Doll and Koie. Analysis of variance was computed and statistical variations were determined as highly significant at 0.01 using MSTAT-c procedure version 5.1. RESULTS: Analysis of variance indicated highly significant differences among treatments for all the characters under all the environments. The genotypes gave different percentage protein, tryptophan and lysine ranges for all locations. P4 gave the highest vale of protein content in all locations. The highest tryptophan and lysine values were obtained from P1 at Gorekhpur, Pantnagar and Kashipur. CONCLUSION: This investigation confirmed the earlier reports that quality protein maize varieties contain two-fold lysine and higher tryptophan. Besides, variations in protein content do exist among cultivars. This study revealed the fact that genetic factor influences the protein, tryptophan and lysine contents of quality protein varieties. Therefore, the QPM genotypes could be incorporated in the breeding program targeted in developing cultivars with high lysine and tryptophan contents to meet protein and aminoacid requirement in developing countries. Alternatively P1 could be grown by the producers and can be used as sources of protein for both children and adult.