Nitrogen Stress of Winter Wheat Changed the Determinants of Yield and the Distribution of Nitrogen and Total Dry Matter During Grain Filling

1981 ◽  
Vol 8 (2) ◽  
pp. 191 ◽  
Author(s):  
WM Blacklow ◽  
LD Incoll

The yields of grain dry matter (DM) and nitrogen (N) of winter wheat (cv. Maris Huntsman) were decreased by 26% and 45% when no fertilizer-N was applied in the spring. Fewer ears per m� and less mass of N per grain were the major reasons for the decreased yields. The low-N treatment decreased the rate and duration of grain filling for N but not for DM. Net assimilation of DM and N by the shoots of the low-N crop ceased at 35 and 28 days after anthesis but both continued, at a declining rate, through to maturity for the high-N crop; rates of grain-filling of DM and N were sustained at a constant rate for 2 weeks more as vegetative DM and N were redistributed. From 28 days to maturity the potential contribution to grain yield of DM and N from mobilized sources was estimated at 65% for both for the high-N crop, and 96% and 87%, respectively, for the low-N crop.

2015 ◽  
Vol 28 (2) ◽  
pp. 155-175
Author(s):  
Witold Drezner

The correlation between the net assimilation rate and the degree of plant tillering are investigated for several varieties of simple winter wheat. The net assimilation rate (E, NAR, An) of the studied varieties for different degrees of tillering, individual shoots and individual plants is described according to the units mg/cm<sup>2</sup> • 24 h. Index of efficiency of assimilation surface (F, LAR, I<sub>S</sub>) is determined in units cm<sup>2</sup>/mg. The tillering ability of vegetative shoots in plaints is a very important factor which increases the total assimilate stirfaice value and the assimilation effectivity of the plant's biomass.


2011 ◽  
Vol 59 (1) ◽  
pp. 35-45
Author(s):  
E. Sugár ◽  
Z. Berzsenyi

The effect of nitrogen (N) fertilisation on the growth of winter wheat varieties was examined in three diverse years using the functional method of growth analysis. The main plot in the two-factorial, split-plot experiment was the N treatment and the subplot the variety. The wheat varieties Mv Toborzó (extra-early), Mv Palotás (early) and Mv Verbunkos (mid-early) were treated with N rates of 0, 80, 160 and 240 kg N ha−1 (N0, N80, N160, N240). The Hunt-Parsons (HP) program fitted a third-degree exponential function to the dry matter and leaf area data. In 2007 and 2008 dry matter accumulation continued up to the N240 rate and in 2009 to the N160 rate. In all three years the highest value was recorded for Mv Verbunkos (4.62 g plant−1 in 2007, 4.63 g in 2008 and 4.51 g in 2009). The highest value of maximum leaf area (237.5 cm2) was found for Mv Verbunkos in the N240 treatment. The maximum values of leaf area in each N treatment, averaged over years and varieties (cm2 plant−1), were as follows: N0: 86.2; N80: 141.0; N160: 164.0; N240: 173.1. The parameter AGRmean exhibited the highest value (8.04 g day−1 102) in the N160 treatment, while among the varieties Mv Verbunkos had the highest mean value (7.18 g day−1 102). The highest value of RGRmean was achieved by Mv Toborzó in the N160 treatment in 2009 (3.94 g g−1 day−1 102). The value of NARmean increased up to fertiliser rates of N160 and N240, with mean values (g m−1 day−1) of N0: 2.35, N80: 2.44, N160: 2.53 and N240: 2.47. The highest value of NAR (3.29 g m−1 day−1) was obtained for Mv Palotás in the N160 treatment in 2008. On average the greatest value of LARmax was recorded in the N160 treatment (172.8 cm2 g−1), while the highest absolute value (213.6 cm2 g−1) was achieved by Mv Toborzó in 2008. The unfavourable effect of the drought in 2007 was clearly reflected in the values of the growth parameters.


1983 ◽  
Vol 10 (2) ◽  
pp. 227 ◽  
Author(s):  
BK Singh ◽  
CF Jenner

The method of culturing detached ears of wheat in a liquid medium has been modified to provide for the culture of ears from anthesis to maturity. For prolonged culture of ears, the presence of the peduncular node was beneficial. Grains developing in ears cultured from 2 days after anthesis until they had ripened germinated normally. By comparison with ammonium or nitrate, glutamine was the better source of nitrogen particularly at low levels of sucrose in the medium; inorganic forms of nitrogen inhibited grain-filling. Setting of grains was apparently dependent upon the availability of carbohydrate and there was no evidence from treatments involving shading for a photomorphogenetic response to reduced light intensity. While grain-filling was sustained by the provision of sucrose supplied artificially, light did nevertheless affect the accumulation of dry matter in the grains.


1980 ◽  
Vol 58 (19) ◽  
pp. 2110-2116 ◽  
Author(s):  
W. N. Migus ◽  
L. A. Hunt

CO2 exchange (CER) and transpiration (TR) rates of flag leaves, penultimate leaves, and the ear of two winter wheat cultivars (cv. Fredrick and cv. Bezostaya-1), were measured at intervals during the life of the flag leaf. These were grown at two levels of nitrogen (N), 105 and 210 mg L−1, supplied from the double ridge stage of apical development. Nitrogen concentrations and dry weights of the flag and penultimate leaves, and of various other plant parts, were also measured.CER of main culm flag leaves of both cultivars declined more slowly from ear emergence to approximately 2.5 weeks postanthesis than either before or after this period. Similarly, the CER pattern of main culm penultimate leaves of Fredrick showed a plateau during this same period. By contrast, CER of the penultimate leaves of Bezostaya declined more uniformly overtime. CER of illuminated ears declined steadily from anthesis, whereas CER in the dark decreased to a maximum negative value approximately 2 weeks postanthesis. Nitrogen treatment had little effect on these CER patterns, with the exception of Bezostaya penultimate leaves, in which the rate of decline was slower for the higher N treatment.Nitrogen concentrations of the flag and penultimate leaves, and in the nongrain ear component, decreased steadily during the grain-filling period for both cultivars and N treatments. Leaf N concentration also decreased during the preanthesis period in Fredrick at both N treatments, and in Bezostaya at the lower N treatment. The time – course of N concentration in the leaves was not closely mirrored by CER, indicating that factors other than the N concentration of the leaves were important in determining the pattern of CER.TR of the flag and penultimate leaves declined from full flag leaf expansion until anthesis and then rose during a 2- to 2.5-week-postanthesis period for both cultivars and N treatments, with the exception of Bezostaya at the lower N treatment. The increase in TR during the filling period suggests that the reduced rate of decline in CER at that time may have resulted, at least partly, because a reduction in gas phase resistance offset an increase in residual resistance.


1995 ◽  
Vol 46 (3) ◽  
pp. 507 ◽  
Author(s):  
JA Palta ◽  
IRP Fillery

The effect of fertilizer N on the growth, post-anthesis water deficits and remobilization of dry matter in spring wheat was measured on a duplex soil at East Beverley, Western Australia. Nitrogen was applied at 15, 30 and 60 kg N ha-1 with half being applied at seeding and the remainder at 35 days after sowing (DAS), immediately before the onset of tillering. The applied N generated differences in early growth (76-117 g m-2) and dry matter at anthesis (410-693 g m-2), mainly through the effect of N on tiller number (120-171 m-2) and tiller size. It also generated differences in the water deficit, particularly after flowering. During the first 21 days after anthesis, midday flag leaf water potential fell at rates of 0.04, 0.07 and 0.13 MPa day-1 at 15, 30 and 60 kg N ha-1 respectively. Grain yield at 60 kg N ha-1 was increased by 20% relative to that of 15 kg N ha-1. The increase in grain yield resulted from an increase in the number of ears and grain number per ear. The high N treatment probably induced the increase in the number of fertile tillers (tillers with an ear), but reduced the grain size by 16% relative to the low N treatment. Contribution of preanthesis dry matter to grain yield was 193 g m-2 for the wheat receiving 60 kg N ha-1, 71 g m-2 for wheat which received 30 kg N ha-1 and only 16 g m-2 for wheat which received 15 kg N ha-1. This indicates that at high N supply, grain growth was substantially supported by pre-anthesis stored assimilates.


Genetika ◽  
2011 ◽  
Vol 43 (2) ◽  
pp. 349-359 ◽  
Author(s):  
Novo Przulj ◽  
Vojislava Momcilovic

Modeling plant growth by mathematical functions is important for understanding plant development and growth. Most of the models of dry matter accumulation in small cereals simulated the period of grain filling while small attention has been devoted to mathematical simulation of vegetative period till anthesis. The aim of this research was to determine the most appropriate polynomial non-linear regression for dry matter accumulation till anthesis in winter wheat. Pobeda, a medium early variety, was used as model genotype for this research. A 5-year field data were analyzed by the forward procedure of stepwise regression. Although the procedure requires the maximum power of the polynomial regression to be used, we suggest using a lower power since it is easier for understanding and explanation and it is taking into account literature sources and biological laws. It can be accepted that quadratic regression model appropriately fits the process of dry matter accumulation till anthesis in winter wheat.


1981 ◽  
Vol 59 (3) ◽  
pp. 415-420 ◽  
Author(s):  
L. A. Hunt ◽  
L. V. Edgington

The growth of a crop of 'Arrow' winter wheat (Triticum aestivum L. em Thell.) was studied in detail from 2 weeks before ear emergence to maturity. Aboveground dry weight increased up to 4 weeks after ear emergence, when it reached a maximum value of 1.4 kg∙m−2, and then decreased marginally. The rate of aboveground dry matter accumulation over a 6-week period beginning 2 weeks before ear emergence averaged 24.4 g∙m−2∙day−1.Rapid ear growth commenced some 2 weeks after ear emergence and continued until after the crop had lost all green coloration. Dry matter accumulation in the ears in the period beginning 3 weeks past ear emergence was greater than accumulation in the aboveground parts of the crop as a whole. This indicated that much of the ear dry matter increase in the latter part of the grain filling period occurred as a result of translocation of previously accumulated assimilates. The stem fraction (including leaf sheaths), the major aboveground reservoir of material that is translocated to the ear, decreased from 800 g∙m−2 at 3 weeks after ear emergence to 493 g∙m−2 at maturity.


2013 ◽  
Vol 409-410 ◽  
pp. 314-317
Author(s):  
Heng Jia Zhang

An experiment was conducted to determine the effect of limited water supply on plant height, leaf area, dry matter and net assimilation rate (NAR) of spring maize. The results indicated that limited water supply had little effect on plant height of maize at six-leaf, twelve-leaf, heading and early grain filling except the end of filling. Leaf growth and leaf area expansion were effectively increased at middle and late maize growth stages under limited water supply and the maximum leaf area was maintained at early grain filling to middle filling. In addition, dry matter accumulation of maize in reproductive organs may be promoted by limited water supply. Finally, limited water supply also had great effect on net assimilation rate of maize and the maximum was maintained at six-leaf to twelve-leaf, followed by heading to silking.


Genetika ◽  
2011 ◽  
Vol 43 (3) ◽  
pp. 549-558 ◽  
Author(s):  
Novo Przulj ◽  
Vojislava Momcilovic

In wheat, rate and duration of dry matter accumulation and remobilization depend on genotype and growing conditions. The objective of this study was to determine the most appropriate polynomial regression of stepwise regression procedure for describing grain filling period in three winter wheat cultivars. The stepwise regression procedure showed that grain filling is a complex biological process and that it is difficult to offer a simple and appropriate polynomial equation that fits the pattern of changes in dry matter accumulation during the grain filling period, i.e., from anthesis to maximum grain weight, in winter wheat. If grain filling is to be represented with a high power polynomial, quartic and quintic equations showed to be most appropriate. In spite of certain disadvantages, a cubic equation of stepwise regression could be used for describing the pattern of winter wheat grain filling.


1975 ◽  
Vol 85 (2) ◽  
pp. 271-279 ◽  
Author(s):  
D. M. Osafo ◽  
G. M. Milbourn

SUMMARYExperiments are described which analyse the effects of date of sowing and of a black petroleum soil mulch on the growth of two maize hybrids. The two hybrids used were Anjou 210, which is late maturing in S.E. England, and Kelvedon 75A, which is an early hybrid.As sowing was delayed from mid-April until the end of May, so there was a greater development of vegetative tissue (mainly stem) and leaf area which reached peaks at a later stage after silking. In Anjou 210 early sowing led to higher grain yields (12%) as the production of peak vegetative weight near to the time of silking allowed dry matter produced after that stage, still at a time of high radiation, to move direct to the oars. Also, the remobilization of the secondary source of grain dry matter, namely previously stored photosynthate from the stem, occurred earlier with early sowing and to a greater extent when a longer grain-filling period was allowed.The hybrid K 75A had a lower vegetative weight, and earlier silking coincided with higher levels of radiation, and the resultant increase in net assimilation rate led to a higher proportion of dry matter being partitioned into the ear. Because this hybrid flowered and senesced early, reserves of stem carbohydrate were low and the time available to transfer carbohydrate to the ear was short, resulting in lower yields than in the later maturing Anjou 210. K 75A also responded unexpectedly to the sowing treatments. Although late sowing gave higher grain yields in both hybrids up to 156 days after sowing, in the case of K 75 A, the early senescence curtailed the continuation of grain fill that would normally give early sowing an advantage and hence the late sown K 75 A produced 10 % more grain.The application of a black petroleum mulch to the surface of the soil to raise soil temperature enhanced the benefits derived from early sowing. Plants given this treatment produced greater leaf areas and vegetative dry weights. As a result more carbohydrate was translocated from the stem during the grain-filling period, increasing grain yield by 13% following an increase in both number of grains and individual grain weight.


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