Differentiation of morphological traits and above-ground mass yield of Poa pratensis ecotypes from Podlasie Province in the initial stage of their development

This paper presents results of examinations carried out in 2006–2007 which aimed at performing initial differentiation of 11 Kentucky bluegrass (Poa pratensis L.) in respect of selected morphological traits and above-ground mass yield quantity. Measurements were carried out in the presence of two standard varieties, i.e. a lawn variety Alicia and a fodder form Skrzeszowicka. The examined population of smooth Kentucky blue-grass ecotypes proved to be relatively uniform in respect of most analysed morphological traits and green and dry matter yield quantity. Among them, object pod02 426 deserves special attention as being characterised by the best uniformity of analysed parameters and attaining higher values in relation to such traits as Lpw, Ll, Szbl and A as well as plant productivity, favourable for meadow use. Thousand seed weight did not significantly affect the value of most analysed traits, except green matter yield (r = – 0,714) and leaf blade mass (r = – 0,581). However, it was observed that forms developing longer vegetative shoots and leaf blades with larger assimilation area during 4 examination months were also characterised by higher yield of green and dry matter

Low level of extra-pair paternity in an urban population of blackbirds

AbstractWe studied extra-pair paternity in a socially monogamous bird, the European Blackbird (Turdus merula). The research was conducted in an urban park in Poland. We obtained genetic samples from 36 broods (123 nestlings) of 21 unique pairs. The proportion of broods with some extra-pair nestlings was 17.1% (6 broods), and overall, 13.1% (16 nestlings) of all nestlings were sired by extra-pair males. In one brood (2.8% of all the investigated broods), we found one egg laid by a female which did not have her own territory in the study area (brood parasitism). These figures are relatively low compared to other closely related passerines. We suggest that mate guarding in the studied population may effectively prevent females from engaging in extra-pair activity, and in the case of females, divorce and serial polygamy are better strategies for enhancing the genetic quality and genetic diversity of their offspring than infidelity