HETEROSIS IN CROSSES AMONG DROUGHT-TOLERANT INBRED LINES OF MAIZE (ZEA-MAYS)

A study was carried out with 28 genotypes, comprising 1 drought-susceptible and 6 drought-tolerant inbred lines of maize (Zea mays L.) and their 21 F1s developed in a diallel-mating design. These genotypes were grown under water-stress conditions during the rainy seasons (kharif) of 1985 and 1986. The data were recorded on leaf area/plant, root length, root weight, root number and pollen-shed period in the field. Stomata number/mm2 leaf area, germination at 15 atmospheric pressure in mannitol solution, proline content and grain yield/plant were recorded in the laboratory. The cross-combinations 'V 50B' x 'CM 205', 'V 20B' x 'CM 205', 'V 50B' x 'H 98' and 'H 98' x 'CM 205' showed high heterosis for grain yield and leaf area in both the years. Heterosis for laboratory tests was not uniform and did not manifest clearly for grain yield.