Seed size effect on yield quantity and quality of maize (Zea mays L.) cultivated in South East Baltic region.

Fractionation of seeds is a process commonly used by breeding and seed production companies. Separation of seeds into small, medium and large size fractions depends on a thousand kernel weight and thus on the content of the endosperm of the seeds, which is used in the process of embryo germination. Research showed that large seeds were characterized by a higher field germination capacity and generally seedlings had greater weight compared to those obtained from small seeds. The question then arises whether such fractionation would promote plant yield improvement. Yields of maize (Zea mays L.) plants of cv. ‘Boruta’ obtained from different size fractions (of different thousand kernel weight) were evaluated in the years 2005–2007. A three-year field experiment showed that yielding of the plants depended on the seed size fraction and decreased with an increase in the size of maize seeds sown. Moreover, in the experiment the germination value of seeds was assessed in cold (10°C) and warm (25°C) tests. The highest germination capacity in both the warm and the cold test (79.0% and 74.0%, respectively) was observed in the small seed size fraction. Germination of large seeds in the cold test was by 6.71% lower (a significant difference) than that of small seeds. The amylolytic activity of three fractions was also examined as indicated by dry and swollen seeds. The results showed the highest activity of amylases in small seeds (7.33 mg maltoze g dry matter -1 min -1 ) and the lowest in large seeds (4.12 mg maltoze g dry matter -1 min -1 ).