The influence of ploidy level on some biochemical characteristics of maize grains with opaque-2 endosperm

Abstract

Maize is an important souse of vegetable protein. However, maize grains contain low protein and the protein is of poor quality, due to deficiencies in essential amino acids like lysine and tryptophan. Conventional breeding methods have been used to overcome this problem, yet, the only possible solution is the use of specific genes. Two of them are opaque2 and floury2, which have been extensively used in breeding maize for protein quality. Difficulties regarding pleiotropic effects of the genes on some important cultural characteristics, determine to find new ways of using these genes. This paper aims to present the results of biochemical analysis of diploid and tetraploid maize grains that contain the opaque-2 (o2) gene. Experiments were conducted at the Department of Plant Biology of the State Agrarian University of Moldova and at the Institute of Phytotechny “Porumbeni” in 2013. The research involved two special maize hybrids approved in Moldova and their tetraploid forms obtained by colchicine treatment. Biochemical analysis of diploid and tetraploid o2 grain was performed by infrared spectroscopy and traditional methods. As a result of the study it was revealed that tetraploid grains show higher protein content and a decrease in starch and fat. Lysine content was almost similar in the two types of grains. As hexaploid endosperm cells of the tetraploid grains are bigger in volume than triploid endosperm cells of the diploid grains, it was concluded that lysine content per cell is double in tetraploid grains.