EVALUATION OF THE COLD TOLERANCE OF YOUNG MAIZE PLANTS IN THE TEMPERATURE-GRADIENT CHAMBER

Six genetically diverse inbred lines with different levels of cold tol erance were investigated at 10 different temperatures from 9 degrees C -18 degrees C at 1 degrees C intervals for 33 days. -There was a signi ficant difference between the inbred lines as regards the cold toleran ce of young plants. -The cold tolerance of the inbred lines gave diffe rent rankings according to the plant trait evaluated. -A 654 and HMv 1 6 produced the most dry matter and F 2 and HMv 307 the least. A very s imilar ranking was found for final plant height, leaf area and fresh s hoot weight. -The dry matter content of the young plants was about 10% at temperatures above 13 degrees C. At lower temperatures (9-12 degre es C) the dry matter content of CM174 was the highest, followed by HMv 307 and HMv 16. -An evaluation of the weekly increment in plant heigh t at 9-12 degrees C showed that F 2 had the longest period of growth, while Mo 17 stopped growing earliest.