PHYSICAL AND PHYSIOLOGICAL ALTERATIONS CAUSED BY NATURAL AGEING OF MAIZE SEEDS OF SINGLE CROSSES AND THEIR PARENTAL LINES

Abstract

In order to detect and to quantify the damage caused by natural ageing of seeds on events involved in the initial stages of maize germination, a physical and physiological analysis of seeds of two ages, 19 and 6 years old, of two single crosses and its inbred parental lines, were performed. The seeds were stored without control of temperature and humidity. A random block design with two replications of 10 seeds each was used. Variables evaluated were: content of humidity, pericap integrity, solute lixiviation, seed viability and radicle protrusion. The results indicated that the physical variables (humidity content and pericarp integrity) remained unchanged during the seed storage period; however, the physiological variables (radicle protrusion and viability) were affected (P ≤ 0.05) by ageing. Solute lixiviation was significantly (P ≤ 0.05) profuse in 19 years old seeds. Correlations between viability and radicle protrusion (0.98 **), viability and leaching out solutes (- 0.66 *), as well as between leaching out solutes and radical protrusion (- 0.66 *), were significant.