Seed reserves reduction rate and reserves mobilization to the seedling explain the vigour of maize seeds

Taxa de redução de reservas da semente e mobilização de reservas para a plântula explicam o vigor de sementes de milho

Abstract:

Understanding how the seed reserve dynamics occurs during germination and seedling formation is determinant for advancements on seed technology. The aims of this study were: to verify which accelerated ageing temperature is the most effective to separate the vigour levels of maize seeds and to evaluate the reserves dynamics during germination and seedling formation process. Seven maize cultivars were submitted to the germination rate, accelerated ageing, thousand seed weight, total seedling length, shoot and root length, dry matter of seed and seedling, remaining dry matter in the endosperm, seed reserves reduction rate, conversion efficiency of reserves, reserves mobilization rate to the seedling and energy expenditure using the completely randomized statistical design. The reserves dynamics and seedling formation depends on the genotype and the initial seed vigour. Accelerated ageing at 45 °C for 72 hours is the most efficient combination to segregate vigour levels. Genotypes with higher seed reserve utilisation efficiency have higher vigour, producing seedlings with higher dry matter, higher total, shoot and root length, regardless of seed weight. The two rates evaluated prompt us to conclude that they explain the maize seed vigour and can be used in quality control programs to select high physiological quality cultivars.

Index terms:
Zea mays L.; seed reserves utilization; germination; physiological quality