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).

The aim of this study was to assess the effects of the agricultural use of sewage sludge in corn for grain, in the year of application and follow up effect after one and two years after its application. The study was conducted on the variety PR39G12 on the field after the 5-year monoculture corn. Sewage sludge was used in accordance with the Directive of Minister of Environment allowing application of 10 t dry mater per ha-1 once every five years. Fertilization with sludge of maize grown for grain did not cause differences in the growth and development of plants, compared to mineral fertilized objects, as well as did not exceed the limit value for heavy metals content in above-ground plant parts. Maize grown using sewage sludge yielded higher than the objects fertilized with mineral, especially in conditions of extreme drought, which occurred in 2006. Beneficial effect of sewage sludge was maintained in the next two years after application and stabilized the grain yield of maize.Keywords: maize, residual effect, sewage sludge, SPAD, yield Abstrakt Celem pracy była ocena efektów rolniczego wykorzystania komunalnych osadów ściekowych w uprawie kukurydzy na ziarno, w roku zastosowania oraz w kolejnych dwóch latach działania następczego. Badania przeprowadzono z wykorzystaniem odmiany PR39G12, na polu po 5-cio letniej monokulturze kukurydzy. Osad ściekowy stosowano zgodnie z ówczesnym rozporządzeniem Ministra Środowiska dopuszczającym aplikację w dawce 10 ton s.m.·ha -1 raz na 5 lat. Nawożenie osadem ściekowym kukurydzy, uprawianej z przeznaczeniem na ziarno, nie spowodowało różnic we wzroście i rozwoju roślin w porównaniu do obiektów nawożonych mineralnie, jak również nie powodowało przekroczenia dopuszczalnych zawartości metali ciężkich w nadziemnych częściach roślin. Kukurydza uprawiana z wykorzystaniem osadów ściekowych plonowała wyżej niż na obiektach nawożonych

Maize (Zea mays L.) grain endosperm is triploid (3n), of which 2n come from the male (transferred by pollen) and only 1n from the female plant, thus a major impact of the male form can be expected on grain quality parameters. A good example of this relationship is the phenomenon of xenia. The aim of this study was to determine the effect of pollen on grain quality. The field experiment was conducted in 2011; seeds were harvested from eight cultivars: Bosman, Blask, Tur, Kozak, Bielik, Smok, SMH 220 and Kresowiak, derived from free pollination and controlled self-pollination of maize. Analyses of nutrient contents and starch content in the grain were conducted in the laboratory. In addition, 1000 grain weight and the hectoliter weight of all grain samples were recorded. The results confirmed differences in grain quality of maize hybrids obtained by self-pollination and by open pollination. Grain of maize plants obtained by open-pollination was characterised by higher contents of N-free extract and starch, and lower protein content. Undertaking further studies on this subject may indicate specific recommendations for agricultural practice, such as mixtures of hybrids with good combining abilities, which will contribute to improved grain quality without additional costs.

The aim of the current study was to assess the degree of damage caused by the cream-bordered green pea (Earias chlorana Hübner), belonging to the family Noctuidae, as well as evaluate the potential control of this pest in a 4-year old plantation of common willow (Salix viminalis L.). Analyses were conducted in the years 2010 and 2011 at the Research and Education Centre Gorzyń, Złotniki Branch, Poznań University of Life Sciences. The occurrence of cream-bordered green pea on clone 1100 of common willow (Salix viminalis L.) was evaluated in two unifactorial experiments. The aim of the first experiment was to assess the residual effect of sewage sludge applied in the year of plantation establishment, while the second experiment analysed the effect of insecticide applications. Analysis of variance did not show any significant residual effect of sewage sludge on the proportion of shoots damaged by the pest, while the application of chemicals significantly limited the volume of damage caused by cream-bordered green pea caterpillars. In both 2010 and 2011, the greatest efficacy in the reduction of the damaged shoots by the cream-bordered green pea (87.2% and 87.8%, respectively) was obtained after the application of esfenvalerate. The highest yield increment in comparison to the control was recorded in 2010 (6.9 t ha -1 , 32.7%).

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