Eleni M. Abraham

Comparative efficiency of three selection methods in Dactylis glomerata L. and Agropyron cristatum L.

Two populations, one non-improved of Dactylis glomerata and one improved of Agropyron cristatum were selected in an isolated spaced plant environment (80 cm) by three selection procedures: (1) Mass honeycomb selection (MHS), (2) pedigree honeycomb selection (PHS) and (3) pedigree honeycomb selection-combined criterion (PHS-CC). The third procedure is a between-families selection based on increased family mean and reduced family coefficient of variation (CV). Response to selection assessed in sward trials in the first and second harvest year was effective for the three procedures, which ranked PHS-CC > PHS > MHS. Evaluation was based on consistent efficiency as measured by both cloned and half-sib families. The precision of assessing progeny performance under sward conditions on the basis of single plant evaluation in the isolation environment, increased with a reduction in competition among plants, the use of moving-ring selection, and the application of high selection pressures (1·6%). The efficiency of selection between unimproved families increased when families were selected concurrently for high family mean and reduced family coefficient of variation.

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.

Molecular, Genetic and Agronomic Approaches to Utilizing Pulses as Cover Crops and Green Manure into Cropping Systems

Cover crops constitute one of the most promising agronomic practices towards a more sustainable agriculture. Their beneficial effects on main crops, soil and environment are many and various, while risks and disadvantages may also appear. Several legumes show a high potential but further research is required in order to suggest the optimal legume cover crops for each case in terms of their productivity and ability to suppress weeds. The additional cost associated with cover crops should also be addressed and in this context the use of grain legumes such as cowpea, faba bean and pea could be of high interest. Some of the aspects of these grain legumes as far as their use as cover crops, their genetic diversity and their breeding using conventional and molecular approaches are discussed in the present review. The specific species seem to have a high potential for use as cover crops, especially if their noticeable genetic diversity is exploited and their breeding focuses on several desirable traits.

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.