摘要:

AbstractPhenotype and forage value, including conservation properties, of grassesThe phenotype of grasses can be influenced by the date of harvest as well as by breeding programs. In contrast to dicotyledons, the stems of grasses are younger than the leaves, although the grass leaves are usually considered to have a higher nutritional value than the stems. In a field experiment,Lolium multiflorumLam. ssp.gaudini(Parl.) Schinz et Kell. was grown as a model‐plant in order to study effects of ploidy‐level, N‐fertilization, stage of development, and growth time on the main aspects of nutritional value and conservation properties in relation to the phenotype.As regards the nutritional value, the interactions of ploidy × plant organ (=stem or leaf) and of ploidy × N‐input were not significant. Hence, the results for leaf and stem can be generahzed. Until the emergence of the inflorescence, EC 49, the stem showed a significant higher net energy content than the leaf; at later stages of development this relationship changed. The evaluation of the net energy content of leaf and stem was significantly influenced by the method of estimation.In vitromethods with rumen liquor may show the best approximation to the real value. The crude protein/energy ratio of the stem as compared to the leaf better meets the nutritional requirements of ruminants; on the other hand the leaf was more valuable than the stem in relation to the nitrate content, especially when the whole plant showed an increased nitrate level. The general relationship between the mineral content and the phenotype was not evident. The investigation indicated significant differences between stem and leaf in relation to their conservation properties. The leaf showed more favourable drying properties than the stem but ensilability was better for the stem than for the leaf. As a result of this investigation it is assumed that, in the past, the nutritional value of young stem has been underestimated whereas the value of the leaf has been overemphasized. This may also be due to the criteria and determination methods of the nutritio

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00180.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractMore detailed information on the causes of yield variability among wheat cultivars is needed to further increase wheat yield. Field studies were conducted in Northern Greece over the two cropping seasons of 1985—1986 and 1986—1987 to assess the effects of nitrogen fertilizer and application timing of the various component traits that determine grain yield, grain nitrogen yield and nitrogen utilization efficiency of two bread (Triticum aestivumL.) and two durum (Triticum durumDesf.) wheat cultivars, using yield and yield component analysis. Nitrogen at a rate of 150 kg ha‐1was applied before planting or 100 N kg ha‐1before planting and then 50 N kg ha‐1top dressed at early boot stage. Nitrogen and cultivars affected all traits examined, while split nitrogen application affected only some of the traits. Grain yields in the most cases were correlated with number of grains per unit area and grain weight and grain nitrogen yields in all cases with grain number per unit area. The contribution of the number of grains per spike to total variation in grain yield among cultivars was almost consistent (37 to 55 %), while the contribution of grain weight was more significant (up to 55 %) in high yields (>6.500kg ha‐1) and number of spikes per unit area (>500). The number of grains per spike contributed from 60 to 83 % to the total variation in grain nitrogen per spike. Increased grain nitrogen concentration resulted in a reduction of its contribution in grain nitrogen yield variation. Nitrogen utilization efficiency was higher during grain filling than during vegetative biomass accumulation. The contribution of nitrogen harvest index to the variation of utilization efficiency for grain yield was higher in plants receiving nitrogen

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00181.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn a field trial located in a northern region of Germany, characterized by a Podzol soil and increasing N fertilization resulted in an enhanced N uptake of the maize (Zea maysL.) variety “Felix” with increasing N fertilization ranging from 0 kg N ha‐1(N1) to 60 kg N ha‐1(N2) and to 160 kg N ha‐1(N3). The growth conditions reached only nearly optimal temperature for biomass allocation in a short period of July and August 1990. The plant productivity was stimulated due to higher N uptake and N utilization to values of nearly 1600 g ha‐1. The N efficiency decreased with increasing N fertilization.A greenhouse experiment was conducted to study the effects of varied nitrogen nutrition on the development of maize plants under standardized growth conditions, comparable to the sub optimal growth conditions of the field experiment. Physiological and anatomical parameters were measured. Within a range of 0.2—1.0 mg N cm‐2of leaf nitrogen, the chlorophyll concentration and the CO2exchange rate showed a linear relationship with the reduced N in the leaf. Above 1.0 mg N cm‐2no further increases in chlorophyll levels or photosynthesis were observed. Nitrate reductase activity was stimulated throughout the N range supplied. The activities of photosynthetic enzymes (PEP carboxylase, Nadpmalic enzyme, RubP carboxylase) was increased from the low (0.19 g N kg‐1soil) to the middle N level (0.37 g N kg‐1soil). Under conditions of a high N supply (0.75 g N kg‐1soil) the activity decreased, except Nadpmalic enzyme. This effect was accompanied by alterations of the internal structure of the leaf. Leaf thickness and size of the mesophyll parenchyma were less at the medium nitrate supply. Other anatomical parameters were influenced in proportion to leaf nitrogen status. Stomatal index was not affected by N supply, but lengths and widths of epidermal and stomatal cells as well as the distance between stomata and vascular bundles were increased by high N supply. It is proposed that above an optimal range of leaf nitrogen, maize plants cannot use the potential advantage of the C4mechanism and the N utilization shows maximum efficiency in the intermediate N level under the sub optimal growth conditions used in th

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00182.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA field study was conducted with the objective of determining the effects of soil moisture on seed yield and quality of mungbean (Vigna radiataL. Wilczek) when grown under rainfed and irrigated conditions in a dry season. Seed quality was determined in terms of germination and production of normal seedlings after controlled deterioration. The presence of adequate soil moisture increased growth and yields of mungbean significantly. The seeds from irrigated plots had a greater weight, owing to heavier cotyledons. Although germination of seeds from the irrigated plots was higher before and after controlled deterioration for 72 h, the number of abnormal seedlings was also greater. Controlled deterioration reduced germination of both categories of seed in the same manner. These factors indicate the low potential of using seeds produced under irrigation in dry seasons as planting material, especially after storage.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00183.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThree field experiments were conducted on chickpea (Cicer arietinumL.) and four on lentil (Lens culinarisMed.) at different winter‐sown rainfed locations in Jordan from 1988/89 to 1990/91 to study the effect of the duration of weed‐free and weed‐infested conditions on yields and yield components of the crops. Chickpea seed yields were reduced on average by 81 % and straw yields by 63 % when fields remained weed infested until harvest compared with weed‐free conditions throughout the growing season. The corresponding lentil seed and straw yield decreases were 63 % and 55 %. As the duration of weed‐free period increased and the duration of weed‐infested period decreased, yields increased. However, the critical period of weed interference was between 35 and 49 days after emergence in chickpea and between 49 and 56 days after emergence in lentil, when these crops were at an advanced stage of vegetative growth. There were significant negative correlations between the weed dry weight and the seed or straw yields. The reduction in seed yields in both crops because of weed interference occurred mainly through the reduced number of pods /plant, which in turn was partly the result of reduced number of secondary branches. In chickpea, some reduction also occurred through reduced 100

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00184.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractFrom 1985 to 1987, eight varieties of domestic and foreign Burley tobacco were studied in some Northern Italy locations (Veneto Region), as an alternative to the air‐cured light and dark tobacco presently grown in that area.An average 3‐year yield equal to or higher than 3 t ha of cured leaf was obtained for all the tested varieties, which indicates a general adaptation to the environment. Early‐flowering types were more productive than late‐flowering ones; the qualitative leaf traits (alkaloid content, combustibility and specific leaf weight) were mainly related to the growing seasons. The yield stability test and the mean leaf yields highlighted the CAS 83–1A and CAS 83‐lE cultivars as high‐yielding and stable genotypes, and Virginia 528 as a medium to high yielding genotype adapted to less favourab

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00185.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn field experiments conducted for 2 consecutive years at Shimla (31°06′N, 77°10′E at 2202 m above mean sea level with potato (Solarium tuberosumL.), weekly means of rainfall (P), potential evapotranspiration (PET), pan evaporation (PAN) and photosynthetically active radiation (PAR) were estimated during the crop season. It was evident that from April to end of June, the evaporative demand was more than the precipitation and that the crop suffered from water deficit from emergence to tuber initiation. Four different energy summation indices accumulated over important phenological stages of growth and energy‐use efficiency in terms of biomass production at these stages were estimated for two seasons. Weekly cumulative biomass production showed a significant correlation with accumulated PET, PAN and PAR in the four genotypes tested in

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00186.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Book review in this articleBajaj, Y.P.S. (ed.), Biotechnology in Agriculture and Forestry. Vol. 22. Plant Protoplasts and Genetic Engineering III. Springer‐Verlag.Bajaj, Y.P.S. (ed.), Biotechnology in Agriculture and Forestry. Vol. 23. Plant Protoplasts and Genetic Engineering I

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00187.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY