Weed Science Commons^™

Mineral Composition Of Vegetation Related To Primary Production In Alluvial Meadow Ecosystems, Jana Jakrlova

IGC Proceedings (1977-2023)

Concentration and ratio of mineral nutrients, dynamics of mineral nutrient uptake per 1 m2, and the contents of mineral nutrients in per­manent biomass reserve and in maximum biomass were assessed in three selected types of meadow ecosystems representing a natural hydrological series in a given area (dry, moist, wet). The assessment was based on chemical analyses (N, P, K, Na, Ca, Mg) and production analysis of above-ground and underground parts of defined vegetation.

Total above-ground biomass produced per year was estimated (from the dry type to the wet one) at 706, 1070, 2430 g • W • m-2, re­spectively; total …

Biomass Budget And Energy Flow In Alluvial Meadow Ecosystem, Milena Rychnovska, Blanka Ulehlova, Jana Jakrlova, Marta Tesrova

IGC Proceedings (1977-2023)

Primary production, production processes, and decomposition have been studied in alluvial meadow ecosystems for 6 years. Water has been found to be the decisive factor in the energy flow and mineral elements turnover. The quality and quantity of production and decomposition processes depend on the oc­currence and duration o( floods. Permanent pool of underground biomass in Alopecurus pratensis stand makes 45.3 %, permanent pool of shoot biomass makes 54.7 % of the total biomass. 19.4 % of the total biomass is taken off as forage. 11. 7 % of shoot biomass is de­composed during the summer season, and 3 .1 …

Current Aspects Of Eco-Physiological Studies Of Meadow Plants, Momcilo Konic

IGC Proceedings (1977-2023)

Basic parameters applied in eco-physiological studies of meadow plants are: water balance (hydration, transpiration intensity, amounts and forms of water, water deficit, etc.), assim­ilation balance (CO2 balance, assimilation performance, compensation effect), matter pro­duction. Eco-physiological studies should be followed by microclimatic measurements and the anatomical analysis of the meadow plants under study. Eco-physiological studies of meadow plants, if performed in a complex and systematic way, constitute the safest basis for detennining the characters of the entire meadow plant com­munity under the concrete conditions of natural factors prevailing in terms of natural condi­tions and human influence.

Landscape Management Problems Of Grassland Utilization In Mountainous Regions Of The Gdr, Peter Hentschel

IGC Proceedings (1977-2023)

In the medium-altitude mountains of the GDR, many meadows cannot be utilized for intensive forage production. Because of their importance for recreation, game feeding and nature con­servation, general afforestation is not possible. A model is presented that allows for every meadow to choose between intensive utili­zation, afforestation, and reservation for other social needs. Management methods for mead­ows not suitable for intensive utilization, espe­cially the employment of herbicides, are dis­cussed.

Warm-Air And Forced-Air Ventilation Drying Of Grass Seeds, Werner Maltry

IGC Proceedings (1977-2023)

For the design of warm-air conveyor driers and of ventilated bins to be used for grass seeds drying, certain parameters of the drying characteristics under varying conditions must be known. Investigations in a climatized cham­ber with seeds from different plant species at varying bulk height, inlet air temperature, and rate of air flow have shown the drying charac­teristics of a layer to be quite similar to those of a single drying crop. The curve of the drying velocity can be approximated by two branches, a first branch with constant drying velocity and a second straight-lined declining branch. The whole oper­ation …

Problems Of Phytophagous And Pollinating Insect Control Of Seed Lucerne In France, Rene Bournoville, Pierre Guy, Jean-Noel Tasei, Alain Delaude F.N.A.M.S

IGC Proceedings (1977-2023)

This paper is concerned with two factors of lucerne seed yields: phytophagous and pollina­tor insects. There are three groups of phytophagous insects, i.e. foliage species: Acyrthosiphon pisum, Apion pisi, Hypera variabilis, Colaspidema atrum; gall midges: Dasyneura ignorata, Conta­rinia medicaginis; and seed pests: Laspeyresia medicaginis, Tychius aureolus, Adelphocoris line­olatus, Lygus rugulipennis, Bruchophagus roddi. Net sweeping, yellow dish trapping, and gall rearing were used for population and flight observation. Laboratory tests were carried out to deter­mine the susceptibility of Miridae bugs, pre­dators, and pollinators to insecticides. The possibility of rearing and multiplying Megachile pacifica was demonstrated. Studies on its local enemies and …

Progress In Grass Seed Production Through Specialization And Concentration, Heinz Hartmann

IGC Proceedings (1977-2023)

Specialization and concentration •in grass seed production require a long-term development programme. Such development programme has to be put into effect planfully and from year to year by all partners involved. The crews in charge of actual production must be in command of up-to-date seed-growing technologies and see with great continuity to their own further education. Both the farms and nationally-owned enter­prises for seed and planting stocks (VEB Saat­und Pflanzgut) must be furnished with efficient machinery and other facilities for adequate col­lection, treatment, and marketing of grass seed. A complex quality-ensuring system has to be established for high-accuracy control and …

The Effect Of Closing Date, Stocking Rate, And Nitrogen Application On Seed And Wool Production From Tall Fescue (Festuca Arundinacea Schreb.) Pastures, Christopher M. Williams, Kevin G. Boyce

IGC Proceedings (1977-2023)

The effects of closing dates, stocking rates, and nitrogen application on seed and wool production of Demeter tall fescue in South Australia are described. Seed production and gross income were greatest at an intermediate closing date (8 September), at the highest level of nitrogen and highest stocking rate. Late closings (6 October and 3 November) resulted in severe depressions in seed yield and gross incomes. Stocking rates of 15 and 30 sheep/ha caused a similar large reduction in seed yield at late closing dates. The gross value of the extra wool produced from late closing date treat­ments (although up to …

New Problems And Results Of Grass Breeding In The Czechoslovak Socialist Republic, Frantisek Bures

IGC Proceedings (1977-2023)

Turf grass species are among the topics of forage grass breeding in Czechoslovakia at present. Breeding goals, however, are highly differentiat­ed, and testing methods have to be adjusted to that diversity of purposes. Agrostis tenuis Sibth., 'Golf variety, is a perennial turf grass which forms short stolons. Tiller formation has been 263/dm2 on average over several years. Its colour is deep green, and the grass is unpretentious in terms of nutrition and soil. Mean root expansibility is 6.9 per cent, mean tensile strength 3,249 kg/cm2, and aver­age compressive strength 112,768 gcm/cm3. Frequent deep mowing is well tolerated. Variety 'K 7' …

Ms- Based Hybrid Breeding In Lolium Perenne L., Inge Gaue

IGC Proceedings (1977-2023)

Hybrid breeding in Lolium perenne is possible by use of male sterility (ms). To get a suitable basis for successful breeding it is necessary to search, analyze, and confirm plants with male sterility. Over four years we have developed fixator lines and ms-analogous lines and began to test their combining ability. The analysis of anther design in 16 ms-analogous lines showed the level of sterility to be highest in the white­steriles. A breeding programme has been devel­oped that makes possible the production of commercial hybrid seed in the 10th year after the beginning of breeding work.

Investigation Of Male Sterility In Lolium Perenne L. As Influenced By Environmental Conditions, Eicke Rudloff

IGC Proceedings (1977-2023)

By means of a classification of anther design, field-grown male sterile clones of Lolium perenne were found to differ greatly from greenhouse­grown clones as to their variability in the phenotypic manifestation of sterility (PMS). Only 8.7 % white-steriles were found as com­pared with the results obtained from field assess­ment. White-steriles were also found in plants that showed a different PMS in the field. In the greenhouse, up to 93 p.c. of the plants were fertiles, with several provenances producing no fertile phenotypes at all. This is indicative of the fact that PMS would be influenced by the gen­otype. Additional nitrogen …

Particularities Regarding The Manifestation Of Cytoplasmic Male Sterility In Dactylis Glomerata L., Grigori Kuleshov, Aelita Kremnina, Valentina Korovina

IGC Proceedings (1977-2023)

Chemical mutagenics were found to induce male sterility in M1 of Dactylis glomerata L., this character being transmitted in the following generations under conditions of open pollina­tion and pair matings. The respective segrega­tions in the families obtained from test cross­ings, open pollination, and pair matings of sterile plants, and the existence of sterility fixers allow to suppose that in M1, M2, and M3 the sterile forms have cytoplasmic male sterility and are represented by recessive homozygotes with sterile cytoplasm. The study of the meiosis of the male-sterile forms induced by chemical mutagenics has revealed that disturbances in the course of …

Association And Breeding In Cocksfoot (Dactylis Glomerata L.), P Rotili, L Zannone

IGC Proceedings (1977-2023)

The aim of this study was to know the impor­tance of the progeny association effects in the evaluation of the combining ability of the parents. The experiment included eight pure stands and twenty-eight binary mixtures. Gener­al domination ability was considerably larger than general association ability. This is due to the fact that situations of competition were generally observed. A good similarity of rank­ing in pure stand and in mixture was observed. In conclusion, the association effects are not important in the evaluation of the combining ability of the parents.

Influence Of Origin And Arrangement Of Components In Hybridization Nursery On The Performance Of A Synthetic Population Of Alfalfa (Medicago Varia Martyn.), Jan Rod

IGC Proceedings (1977-2023)

Using 7 clones and their immediate progenies (strains), two conforming hybridization nur­series were laid out. The components crossed were planted in close pairs without mutual space isolation but with one meter distance between the pairs. Arrangement corresponded with a Greek-Latin square with two replications of the same combination. Under conditions of open pollination, seed setting was lower in the clone nursery. A per­formance decline took place in strain progenies, i.e. in the generation after one reproduction. Replication of the same combination was typi­cal in both cases. The differences between the performance of progenies of individual com­binations show that, using the …

Acceleration Of Red Clover Breeding (Trifolium Pratense Subvar. _Praecox Witte) By Inclusion Of Greenhouse-Grown Generations, Rolf Gaue, Warner Schweiger

IGC Proceedings (1977-2023)

An outline is given of several possibilities for shortening the breeding period by using meth­ods of generation acceleration in red clover under artificial environmental conditions in the greenhouse. It is possible both to realize com­plete reproduction cycles in the greenhouse within 120 and 180 days, and to produce clover seed within 80 days when using plants that had already passed preliminary field selection for seed productivity. Details of the rearing con­ditions, of the illumination period, and of the sources of light used illustrate the effect of the varied environmental conditions. Honey bees have successfully been used for pollination.

Breeding Tall Fescue (Festuca Arundinacea Schreb.) And Cocksfoot (Dactylis Glomerata L.) For Seedling Establishment Under Conditions Of Competition, Samuel Badoux

IGC Proceedings (1977-2023)

Possibilities of breeding tall fescue (Festuca arundinacea Schreb.) and cocksfoot (Dactylis glomerata L.) for a better establishment rate were studied under conditions of competition. Tall fescue selection for seedling fresh weight and tiller number was conducted for 3 gener­ations. For both characters, estimates of her­itability h2 = 0.57 and h2 = 0.33, respectively, were obtained. The date of appearance of the first tiller was highly correlated with tiller number two months after sowing. Cocksfoot varieties with a rapid establish­ment in greenhouse experiments presented a higher proportion of cocksfoot when used as a compound of a seed mixture.

Results Regarding The Accelerated Production Of Complete Generations Of Lolium Perenne L. And Dactylis Glomerata L. Under Artificial Climate, Joachim Buhring, Karin Neubert

IGC Proceedings (1977-2023)

Studies were performed on Lolium perenne L. and Dactylis glomerata L. for accelerated pro­duction of plant generations. Flowering of Lolium perenne - was induced in single-leaf seedlings by 65-day vemalization at + 4.5 °C, short-day conditions, and low intensity of illumination (30 microeinsteins • m-2 • s- 1 ). In Dactylis glomerata, flowering was achieved within 100 days by vernalization at low to medium temperatures, short-day conditions, and high intensity of illumination (440 micro­einsteins • m-2 • s- 1). Accordingly, by means of refrigerators for producing low temperatures during vernalization and with artificial light, one generation of Lolium perenne can …

Evaluation Of Quality Factors In Warm Season Forages, Warren G. Monson, Gkenn W. Burton, Wayne W. Hanna

IGC Proceedings (1977-2023)

Improved forage quality is a feasible objective. Coastcross-1 bermudagrass, Cynodon dactylon (L.) Pers., selected for high dry matter digest­ibility, has consistently enhanced the perform­ance of the animals consuming it. Variation in quality factors of other species, particularly Paspalum notatum var. Saurae Parodi and Pennisetum americanum (L.) K. Schum., makes it possible to improve digestibility. Pearl millet varieties with improved animal­production potential have been developed and released for farmer use. The varieties have been selected for higher digestibility and short stature, with reduced stem fractions. The assessment of the digestion of fresh forage permits evaluation of the effects of other factors, …

Intra-Specific Variation In Rates Of Dark Respiration And Of Photosynthesis At Low Positive Temperatures In Festuca Rubra L., William S. Stewart, John H. Ollerenshaw

IGC Proceedings (1977-2023)

Low temperature is a primary limiting factor to the growth of grass in the uplands of Britain. Types better able to grow at low temperature are required for the extension of the growing season. Higher rates of dark respiration are considered to be an adaptation to growth at low temperature. An ecotype of Festuca ruhra L. from a cold environment is shown to have higher rates of dark respiration, photosynthesis, and growth at low temperature than one from a warmer habitat. Observation of this kind may form the basis of a laboratory test for rapidly selecting ecotypes able to grow …

The Inheritance Of Sodium Content In The Dry Matter Of Dactylis Glomerata L., Jaroslav Nasinec, Vaclav Mika

IGC Proceedings (1977-2023)

Experiments were carried out about the indi­vidual composition of the variety 'Milona', its parental varieties 'Aberystwyth Sl43' and 'Welta', and random-selection cross progenies which took part in the formation of the popu­lation of 'Milona'. It was stated that the inter­mediary character of the Na content of 'Milo­na' is not due to a medium or nearly medium Na content of the individual plants, but is expressed by the number of single plants whose Na content exceeds the limit of 0.015 % in the third cut. 'Aberystwyth S 143' and some proge­nies in which A-S 143 was used as mother plant, are …