Z. M. Parissi

Growth, dry matter production, phenotypic plasticity, and nutritive value of three natural populations of Dactylis glomerata L. under various shading treatments

Dactylis glomerata L. is a widespread perennial grass species, which has been reported to be adapted to shaded conditions. Its populations thrive in a variety of environments. However, little information is available concerning the comparative response of its natural populations from contrasting environments under the reduced light intensity conditions that exist in silvopastoral systems. The objective of the present study was to estimate the comparative ability of three populations of D. glomerata from northern, central and southern Greece to grow under full sun, 60xa0% shade and 90xa0% shade in terms of their growth characteristics, phenotypic plasticity, dry matter production and nutritive value. Shade reduced tillering and dry matter production, increased tiller height and modified leaf characteristics. Under shade fewer leaves were grown simultaneously on the same tiller, but these werexa0longer and thinner compared to full sun. Differentiation in response to shade among the populations examined of D. glomerata was observed mainly for leaf characteristics. The population from Pertouli (central Greece) responded better, particularly to moderate shade as it hadxa0a higher leaf area, longer leaf and higher dry matter production, compared to the others. Evidence for adaptive phenotypic plasticity to moderate shade was suggested only for this population. Additionally, Pertouli had higher nutritive value compared to Taxiarchis (northern Greece) and Crete (southern Greece) under shade. The divergent responses of natural populations of D. glomerata could justify breeding germplasm with enhanced shade tolerance.

Threats to Mediterranean rangelands: a case study based on the views of citizens in the Viotia prefecture, Greece.

Rangelands in Greece constitute a very important natural resource as they occupy 40% of the total surface. Not only is their forage production essential for the development of extensive livestock farming, but also they play a key role in outdoor recreational activities, protection from erosion, provision of water supplies and biodiversity conservation. However, land use changes, inappropriate management and wildfires threaten their existence. The research was conducted among the citizens of Viotia prefecture, an area close to Athens, Greece, using personal interviews with a structured questionnaire in 2008. The aim was to record citizens opinions regarding the threats to rangelands. The results suggest that the main threats as perceived by the respondents, are land use changes especially for urban development, and wildfires. The application of cluster analysis highlighted the differentiation among the respondents in ranking these threats. The more ecologically aware citizens recognised that mismanagement, abandonment and agriculture also threaten rangelands. These threats can have a considerable impact on the lives of the local people. Policy makers and managers should take the opinions of local citizens into consideration, and engage them in decision making so that sustainable management policies could be applied.

Effect of selenium on mineral content and nutritive value of Melilotus officinalis L.

Plants of Melilotus officinalis L. were subjected to two different treatments: a) no selenium (Se), and b) addition of 3 mg Se L−1 irrigation water for 45 days and samples of leaves, stems and roots were analyzed for Se, potassium (K), sodium (Na), magnesium (Mg), iron (Fe), copper (Cu), calcium (Ca), manganese (Mn) and zinc (Zn). Crude protein (CP) content, neutral detergent fiber (NDF), acid detergent fiber (ADF) and in vitro organic matter digestibility (IVOMD) were also estimated for the aerial plant tissues. In Se-treated plants Se mainly accumulated in leaf tissues, various changes in macronutrient concentrations were detected, while the micronutrient content decreased significantly. In addition, leaf CP, NDF and ADF content decreased, while IVOMD increased, possibly indicating ameliorated nutritive value. According to our findings, M. officinalis could be used either as a dietary supplement, in mixture with non-accumulator species, for livestock feed deficient in Se or for restoration of grasslands in seleniferous soils.

Defoliation frequency effects on winter forage production and nutritive value of different entries of Dactylis glomerata L.

Abstract The objective of this study was to evaluate the effect of different defoliation frequencies on winter forage production and nutritive value of improved populations of Dactylis glomerata L. Four entries: (a) base population, (b) selected plants from mass honeycomb selection (MHS), (c) selected plants from pedigree honeycomb selection (PHS), and (d) selected plants from pedigree honeycomb selection using the combined criterion CC = x 2 (1 ‐ CV)/CV (PHS(CC)) were tested under four defoliation frequencies: (1) frequent, (2) moderate, (3) infrequent, and (4) control. Dry matter (DM) production under the frequent and moderate defoliation frequencies was 17% and 7% respectively more than under infrequent defoliation in the first year. However, in the second year, DM production under infrequent defoliation was 41% and 46% higher than under frequent and moderate defoliation, respectively. The DM production of the selected populations (b, c and d) of D. glomerata consistently exceeded that of the base population (a) under various defoliation frequency regimes during winter. Among the selected entries, MHS and PHS(CC) had consistently higher DM production than PHS for the two experimental years. Under increased defoliation frequencies, crude protein content significantly increased and neutral detergent fibre and acid detergent fibre significantly decreased compared with the control defoliation treatment in both years. There were no significant differences (P > 0.05) in nutritive value among the entries. Generally, DM production was more stable under infrequent defoliation, while nutritive value met the demands of small ruminants for maintenance and lactation.