EFFECTS OF PRIMING METHODS ON SEED PHYSIOLOGICAL QUALITY ASPECTS IN HYBRID MAIZE (Zea mays L.) SEEDS UNDER DIFFERENT STORAGE CONDITIONS
Seed production and grain cultivation are parallel in their production time and therefore call for storage of seeds close to six months to be used later for grain production. Storage of maize seeds under ambient condition in the tropical areas where temperatures are high cause rapid loss in seed quality. Seed priming methods are known to increased and enhance rapid seed germination to achieve vigorous seedlings. The objective of this study was to assess the germination and vigour loss under two storage conditions and to identify the optimum priming concentrations for improving seed germination and seedling vigour. After the six months storage, 10% and 6% germination losses were observed under ambient and cold room conditions respectively. The priming treatments used were 0.5%, 1.0% and 1.5% of NaCl for halopriming method; 50 ppm, 100 ppm and 150 ppm GA3 for hormonal priming and -0.5 MPa, -1.0 MPa and -1.5 MPa polyethylene glycol 8000 for osmo-priming. Results indicated that 100 ppm GA3 concentration increased the root length, shoot length, seedling length, germination percentage, speed of germination, and seedling vigour indices with less mean germination time and time to reach 50% germination under laboratory condition. Among all the halopriming treatments examined, 0.5% NaCl was the best for germination percentage, speed of germination and seedling vigour indices while among the osmo-priming concentrations, -1.0 MPa PEG out-performed the other concentrations for the germination characters observed. The same priming concentrations were repeated on the field. Again the 100 ppm GA3 of hormonal method recorded the highest seedling emergence and vigour index II followed by the 0.5% NaCl halopriming concentration. It was deduced from the result that priming with 100 ppm GA3 was the best method that can be employed to increase germination and seedling vigour.