摘要:

AbstractCrop management influences considerably the three components of grain yield, growth duration, growth rate, and harvest index (HI). Effects of seeding rate on these yield components in oats (Avena sativaL.) was assessed in field experiments at the Viikki Experimental Farm, University of Helsinki, Finland (60°13′N) in 1991 and 1992. Three Finnish oat genotypes were evaluated; a long‐strawed landrace cultivar, a moderately long‐strawed modern cultivar, and a semi‐dwarf breeding line. The following traits were measured: grain yield, days from sowing to yellow ripeness, number of tillers on main shoot, phytomass, vegetative phytomass, and their growth rates (PGR and VGR, respectively), panicle weight and its filling rate (PFR), HI, leaf area index (LAI), and at intervals, dry‐matter accumulation in leaves and straw.Increases in seeding rate significantly decreased growth duration and PGR of individual plants but increased PGR on a ground area basis. Seeding rate did not, however, affect HI. When seeding rate was increased from 200 seeds m−2to 500 seeds m−2, reductions in vegetative phytomass, panicle weight, VGR, and PFR for individual plants ranged between 20 and 40 %, depending on genotype. At ≥600 seeds m−2differences in these components between seeding rates were modest. However, PGR, VGR, and PFR per unit ground area increased with increasing seeding rates up to 600–700 seeds m−2. Moreover, the higher the seeding rate, the higher the peak LAI (2.7 maximum) and the earlier the canopy closure. Hence, our results showed that a seeding rate of 600–700 seeds m−2, which resulted in uniculm growth habit, is advantageous in terms of grain yield at high latitudes due to higher biomass accumulation and subsequently g

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00550.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractYield formation in cereal‐rich crop rotations and monocultures in an extensive and intensive crop‐management systemIn a long duration trial, conducted from 1979/80 to 1992 at TU‐Munich's research station in Roggenstein, the performance of monocultures of winter wheat, winter barley and winter rye, as well as numerous cereal‐crop rotations were compared in an extensive and intensive crop‐management system. The results obtained can be summarized as follows.Over the course of 13 years, the influence of the immediately preceding crop on the yield of the main crops was of much greater significance than the rotation as a whole. With winter wheat, no yield differences could be observed between monoculture and cereal crop rotation (if the rotation did not include oats). Oats, rape, field bean, pea, potato and maize as preceding crops, however, in crop management systems, led to, on average, an increase in yield of 13 dt/ha from the following wheat. Winter barley yields were not significantly different in monoculture, cereal crop rotations and crop rotations containing 66% cereals. Furthermore, winter rye yields were the same in monocultures and cereal crop rotations. With all cereals, intensification of fertilizing and chemical plant protection led to a considerable increase in yield, but did not diminish the effects of the preceding crop. Hence, even with the use of modern agronomical techniques it is impossible to compensate for yield losses due to crop

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00551.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA 2‐year trial has been carried out in northern Italy on soybean (cv. Hodgson) grown in lysimeters, comparing three soil water regimes (well‐watered conditions and water stress during vegetative and reproductive stages) at two sowing dates. Plant evapotranspiration and water uptake depth were calculated from volumes of water independently supplied to eight lysimeter layers; at harvest, plant architecture, yield components and fruit distribution along the main stem and lateral branches were evaluated.Although water stress intensity was not severe, crop evapotranspiration and water uptake depth were severely restricted by water shortage. Both low water‐availability and late sowing significantly modified the architecture of plants, decreasing total height, number and length of internodes and lateral branches. Seed allocation along the stem was shifted downwards both by delaying the sowing date and by reducing the water supply; the component most responsible for yield decrease was the number of pods per plant, while unit seed weight was only slightly affected by water stress. Grain yield reduction was higher when water availability was inadequate during the reproductive phase in the early‐sown crop and during the vegetative stage in the late‐sown crop. This suggests that the intensity of the water shortage, plant phenological stage of stress application, as well as the date of stress application within the growing season determine the yield response o

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00552.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractVernalization requirements and cold resistance of 13 lines of winter rape derived from doubled haploids obtained by androgenesis were investigated. The degree of vernalization requirements was examined in two parallel experiments. In the first experiment seedlings aged 2 weeks were vernalized during 63 and 35 days under controlled conditions, at 5 °C. In the second experiment the natural conditions of vernalization were differentiated by sowing the plants at four different dates in spring: March 15th, April 15th, May 15th, and at the latest date excluding vernalization, June 5th. The lines examined revealed differentiation of vernalization requirements that were similar in both experiments; all the lines required a period of exposure to cold before flowering. Cold resistance of lines was estimated in two successive series at −15 °C and −17 °C. Before testing the plants were kept in natural field conditions from the beginning of September until the middle of November. Testing of cold resistance was preceded by hardening under controlled conditions. Considerable differences in cold resistance was found in the forms investigated.The results obtained do not show any relation between frost resistance and the degree of vernalization requirements, as the line characterized by the strongest winter habit of growth showed low cold resistance, whereas the lines which were closer to spring growth habit showed the highest level of cold resistance; the lines with the least vernalization requirements revealed the highest level of cold resistance. This conclusion can be confirmed by the significance of the correlation coefficients between the various indices defining the frost resistance and the indices of vernalization requir

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00553.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThirty‐six accessions of linseed (Linum usitatissimumL.) were screened for salt tolerance at the seedling stage after 2 weeks growth in solution culture salinized with 150mol m−3NaCL Considerable variation in salt tolerance was observed in this set of germplasm. Two salt‐tolerant accessions, T‐5(69‐S9)B and LS‐2 and two salt‐sensitive accessions P‐70 and Aver‐Rer‐Seic, selected at the seedling stage, were grown to maturity in sand culture salinized with 0 (control), 70, 140, and 210 mol m−3NaCl. Both the salt‐tolerant accessions exceeded the two salt‐sensitive accessions in biomass production, seed yield, and yield components, but the accessions did not differ significantly in seed oil content in the salt treatments. The tolerant accessions accumulated greater amounts of Na+in the shoots and less in the roots compared with the salt‐sensitive accessions. The shoot K+, K: Na ratios, and K+versus Na+selectivity were lower in the salt‐tolerant accessions compared with the salt‐sensitive accessions; the reverse was true for their roots. Contributions of Na+and Ca2+to osmotic adjustment were much higher in the two salt‐tolerant accessions than in the salt‐sensitive ones.It has been established that there is a great deal of variation for salt tolerance in linseed. The degree of salt tolerance of this crop does not vary during ontogeny. The physiological basis of salt tolerance of this species appears to be associated wit

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00554.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractGrowth responses of 12 wheat cultivars and their phosphorus utilization were studied in a greenhouse. They were grown for 18 days in a solution containing rock phosphate as the phosphorus (p) source. Biomass of 26 day old plants of all the cultivars varied significantly whereas their shoot to root ratio stayed constant. The dry matter yield of all the 12 cultivars was significantly correlated with the p uptake (r = 0.74). Whereas the higher p uptake by all the cultivars was significantly (P<0.01) related to the drop in the root medium pH, which was presumably owing to the H+efflux from their roots. The wheat cultivar Blue Silver proved to be the most efficient p user and therefore seems to have the highest potential of making best growth in soils with poor p availability among the 12 wheat cultivars under investigation.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00555.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractNear infrared reflectance (NIR) spectroscopy is a rapid, inexpensive, and simple technique used to make quantitative analyses of the concentration of nutrients in plant tissue. In this field experiment, the potential usefulness of NIR analysis for the study of lipid concentrations in the aerial plant tissues of maize (Zea maysL.) was evaluated using a fairly simple and inexpensive NIR unit (Inframatic 8100, Per Con Prügeräte GmbH, Germany). Lipid concentration values were measured by standard Soxhlet techniques, which were used to calibrate the instrument for plant samples taken at tasselhng, 3 weeks after pollmation, and plant maturity. Reflectance readings, obtained using seven filters, were fitted to Soxhlet values using multiple linear regression, and regression constants were obtained. The results showed that correlation coefficients between Soxhlet lipid concentration and NIR value obtained were 0.999 and 0.995 for grain lipid and stover lipid, respectively. Standard errors of the estimated values were 0.5929and 0.5562for maize grain and maize stover when the six wavelengths were used, indicating a level of accuracy sufficient for analytical purpose

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00556.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe photosynthesis, shoot formation, leaf area development and dry matter production were examined in control and de‐eared plants ofT. monococcumvar. G 1372andT. aestivumvar. Sonalika. The removal of ears decreased the diurnal maintenance of photosynthesis and consequently, the dry matter production in Sonalika but not in G 1372. There was a considerable growth of alternative sinks such as shoots and roots when ear sinks were removed. This alternative sink capacity of de‐eared plants seemed to have compensated for limited sink demand of ears in G 1372but could not entirely compensate for the more efficient grain sink in Sonalika. The diploid wheat produced more dry matter than the hexaploid wheat in the pre‐ear emergence period and less in the post‐ear emergence period. In the preear emergence period, the difference in dry matter appeared to be mostly because of the difference in duration to ear emergence. During the post‐ear emergence period, the lower dry matter in G 1372seemed to be owing to a rapid decrease in photosynthesis rate after anthesis because of the lower sink capacity of i

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00557.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractContribution of the upper laminae designated as 7, 8 and 9 (flag), to the total reduced nitrogen was determined by two different methods; integration of nitrate reductase activity over the entire growing season of individual laminae, and laminae removal at ear emergence. The values obtained by these methods were: 20, 14, and 12 %, and 23, 15, 12 %, respectively. Thein vivonitrate reductase activity was relatively higher in the lamina 9, which contributed an extra 8 % towards total reduced nitrogen when the other laminae were removed from the shoot. No such compensatory response was observed when either lamina 7 or 8 was retained.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00558.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA Reid experiment was conducted to study the effect of soil moisture on growth of two mustard cultivars using classical and functional techniques of growth analysis. Two soil moisture levels were irrigated at 10‐day intervals and a rainfed control was included. Total dry matter (TDM), leaf area index (LAI) and leaf area duration (LAD) were significantly increased by irrigation at most of stages of growth. Starting from a lower value, LAI and LAD reached a peak and then gradually declined. Among the growth attributes, crop growth rate (CGR), leaf area ratio (LAR) and leaf weight ratio (LWR) increased significantly under irrigation. Net assimilation rate (NAR) decreased more in the irrigated plants than the rainfed plants at the later stages of growth. LAR and LWR declined throughout with increasing time and plant weight. Seed yield of the irrigated plants was positively correlated with the pre‐flowering LAI and the post‐flowering CGR and NAR. In the rainfed plants, seed yield was positively correlated with LAI and CGR at the post‐flowering stage and negatively with the post‐flowering NAR and pre‐fl

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00559.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY