Yield components and nitrogen partitioning of maize in response to nitrogen before and after anthesis

1987 ◽  
Vol 38 (6) ◽  
pp. 1001 ◽  
Author(s):  
CJ Pearson ◽  
BC Jacobs
Keyword(s):  
Dry Weight ◽  
Grain Filling ◽  
Nitrogen Supply ◽  
Nitrogen Partitioning ◽  
Grain Number ◽  
Plant Parts ◽  
Before And After ◽  
Grain Nitrogen ◽  
Effect On Yield ◽  
Nitrogen Treatments

Zea mays hybrid XL66 was grown with irrigation in sand in the field and subjected to different rates of nitrogen supply from floral initiation to anthesis and again from anthesis to maturity. Nitrogen supply during spikelet differentiation affected grain number markedly. Nitrogen supply during grain filling had a small but significant effect on the rate of grain filling and an effect on the rate of nitrogen entry to the grain, causing a 1.3-fold change in percentage grain nitrogen. Increasing the nitrogen supply produced larger plants, but the distribution of nitrogen and dry weight among plant parts were similar and the harvest indices for dry weight (0.46) and nitrogen (0.66) were the same over all nitrogen treatments. We found no evidence that shoot size per se controlled grain number or rate of grain growth; rather, fertilizer management during spikelet differentiation had most effect on yield of XL66.

Characteristics of the canopy, root system and grain yield of a crop of Lupinus angustifolius cv. Unicrop

1975 ◽  
Vol 26 (3) ◽  
pp. 497 ◽  
Author(s):  
EAN Greenwood ◽  
P Farrington ◽  
JD Beresford
Keyword(s):  
Carbon Dioxide ◽  
Grain Yield ◽  
Leaf Area ◽  
Time Course ◽  
Dry Weight ◽  
Grain Filling ◽  
Main Axis ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Plant Parts

The time course of development of a lupin crop was studied at Bakers Hill, Western Australia. The aim was to gain insight into the crop factors influencing yield. Weekly measurements were made of numbers and weights of plant parts, and profiles of roots, leaf area and light interception. A profile of carbon dioxide in the crop atmosphere was taken at the time of maximum leaf area, and the net carbon dioxide exchange (NCE) of pods was estimated for three successive weeks. The crop took 10 weeks to attain a leaf area index (LAI) of 1 and a further 9 weeks to reach a maximum LAI of 3.75, at which time only 33% of daylight reached the pods on the main axis. Once the maximum LAI was attained at week 19, leaf fall accelerated and rapid grain filling commenced almost simultaneously on all of the three orders of axes which had formed pods. Measurements of NCE between pods on the main axis and the air suggest that the assimilation of external carbon dioxide by the pods contributed little to grain filling. Grain dry weight was 2100 kg ha-1 of which 30%, 60% and 10% came from the main axis, first and second order apical axes respectively. Only 23% of the flowers set pods and this constitutes an important physiological limitation to grain yield.

Factors Influencing the Rate and Duration of Grain Filling in Wheat

1977 ◽  
Vol 4 (5) ◽  
pp. 785 ◽  
Author(s):  
I Sofield ◽  
LT Evans ◽  
MG Cook ◽  
IF Wardlaw
Keyword(s):  
Growth Rate ◽  
Grain Yield ◽  
Grain Growth ◽  
Dry Weight ◽  
Grain Filling ◽  
Close Relation ◽  
Grain Number ◽  
Lag Period ◽  
The Difference ◽  
Leaf Photosynthetic Rate

Controlled-environment conditions were used to examine the effects of cultivar and of temperature and illuminance after anthesis on grain setting and on the duration and rate of grain growth. After an initial lag period, which did not differ greatly between cultivars, grain dry weight increased linearly under most conditions until final grain weight was approached. Growth rate per grain depended on floret position within the ear, varied between cultivars (those with larger grains at maturity having a faster rate), and increased with rise in temperature. With cultivars in which grain number per ear was markedly affected by illuminance, light had relatively little effect on growth rate per grain. With those in which grain number was less affected by illuminance, growth rate per grain was highly responsive to it, especially in the more distal florets. In both cases there was a close relation between leaf photosynthetic rate as influenced by illuminance, the rate of grain growth per ear, and final grain yield per ear. The duration of linear grain growth, on the other hand, was scarcely influenced by illuminance, but was greatly reduced as temperature rose, with pronounced effects on grain yield per ear. Cultivars differed to some extent in their duration of linear growth, but these differences accounted for less of the difference in final weight per grain than did those in rate of grain growth. Under most conditions the cessation of grain growth did not appear to be due to lack of assimilates.

Studies of grain production in Sorghum bicolor (L. Moench). IV.* Some effects of increasing and decreasing photosynthesis at different stages of the plant's development on the storage capacity of the inflorescence

1975 ◽  
Vol 26 (1) ◽  
pp. 25 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson
Keyword(s):  
Storage Capacity ◽  
Developmental Stages ◽  
Light Transmission ◽  
Plant Competition ◽  
Grain Filling ◽  
Floral Initiation ◽  
Grain Production ◽  
Grain Number ◽  
Plant Parts ◽  
Sorghum Bicolor L

Sorghum plants (cv. RS610) grown in field stands at two population densities were manipulated to increase the supply of assimilates (by removing neighbouring plants) at one of three developmental stages—10-15 days after floral initiation, 1 week prior to three-quarters anthesis, and 1 week after three-quarters anthesis. Post-initiation exposure increased the number of grains per inflorescence 1.8-fold and 3.5-fold in medium and high density populations respectively, but had relatively less effect on grain size. Higher grain number resulted largely from more grains per secondary branch in the lower part of the inflorescence. Neither of the post-heading exposure treatments influenced grain number, but the higher supply of assimilates resulted in larger grains at both densities. Differences at one density only between yield characteristics of plants exposed at the two times provide evidence of inter-plant competition for assimilates to the extent that the potential size of the grain may be affected. Shading (10% light transmission) of plants grown in a glasshouse, whether for 1 week at anthesis or during grain filling, reduced grain yield at maturity by the same amount as the immediate reduction at the end of the shading period. The experiment was unable to demonstrate changes in the potential size of grains resulting from the loss of assimilates at anthesis. There was substantial compensation for the loss by translocation from other plant parts. *Part III, Aust. J. Agric. Res., 26: 11 (1975).

Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat

2011 ◽  
Vol 150 (4) ◽  
pp. 442-459 ◽  
Author(s):  
L. LÁZARO ◽  
P. E. ABBATE
Keyword(s):  
Solar Radiation ◽  
Field Experiments ◽  
Dry Weight ◽  
Grain Filling ◽  
Wheat Cultivars ◽  
Grain Number ◽  
Incident Solar Radiation ◽  
Fertility Index ◽  
Sowing Dates ◽  
Intercepted Solar Radiation

SUMMARYIn wheat, the photothermal quotient (Q, the ratio between mean incident solar radiation and mean temperature is greater than 4·5°C in the 30 days preceding anthesis), is a good estimator of grain number/m2 (GN) and of yield. Previous investigations have not analysed in depth whether the responses of GN to Q differ between wheat cultivars, or what is the cause of the eventual variation. In the present work, the results of field experiments carried out between 1994 and 2001 in various locations were used to test the following hypotheses: (i) the responses of GN to Q differ between wheat cultivars; (ii) these differences are caused by differences in the spike fertility index (GN/g spike dry weight/m2 at the beginning of grain filling (SDW)). The responses of GN to Q were compared for five wheat cultivars (four bread wheats and one durum wheat) and it was found that with Q values above 0·3 MJ/m2/d°C, all responses of GN to Q were linear, positive and parallel. A method was then proposed to obtain cultivar-specific GN from a common relationship between GN and Q. This method would facilitate GN estimation in crops with changes in sowing dates, sites or years, starting from data of potential GN and yield that is relatively easy to obtain. Differences among cultivars in response to Q were due to differences in GN response at SDW. Similar SDW values produced different GN, depending on the spike fertility index of each cultivar. The cultivars did not differ in their responses of SDW to Q. The association between spike fertility index and SDW was strongly negative in bread wheat. At lower levels of Q or SDW, the spike fertility index increased in all cultivars, at least when changes in SDW or Q were caused mainly by intercepted solar radiation, but the present results demonstrate that differences between cultivars also exist in this relationship.

A method of screening for spike fertility in wheat

2012 ◽  
Vol 151 (3) ◽  
pp. 322-330 ◽  
Author(s):  
P. E. ABBATE ◽  
A. C. PONTAROLI ◽  
L. LÁZARO ◽  
F. GUTHEIM
Keyword(s):  
Screening Method ◽  
Dry Weight ◽  
Grain Filling ◽  
Relative Standard Error ◽  
Grain Number ◽  
Crop Physiology ◽  
Plot Size ◽  
Relative Standard ◽  
Crop Maturity

SUMMARYWheat grain yield is often associated with grain number/m2. Spike fertility (SF), i.e. the quotient between grain number and spike chaff dry weight, is a major component of grain number/m2 determination. Several methodologies have been proposed in the literature for field determination of SF, but they are tedious and expensive. Also, no comparison between methodologies has been done. The feasibility of using wheat SF as a selection criterion in a breeding programme or as a variable of interest in crop physiology studies depends largely upon the availability of a simpler and faster method for collecting and processing samples. Thus, the objective of the present study was to determine: (1) the association between SF calculated with the non-grain spike dry weight at anthesis (reference method) or at crop maturity, (2) the association between SF evaluated at the plot level (i.e. both non-grain spike dry weight and grain number determined as per area unit) and at the individual spike level and (3) the minimum number of individual spikes that should be sampled for the development of a screening method that can be applied in wheat breeding programmes or in crop physiology studies. Associations between variables were determined by correlation analysis of treatment means, and by a test of agreement for categorical rating (low, medium and high SF) between individual data of each variable. Four experiments (BY95, BC96, BC97 and ML07) were performed with five, ten, eight and eight wheat cultivars, respectively, under no environmental limitations, except for experiment ML07 which was not irrigated. In the first three experiments, SF was determined both at the beginning of grain filling and at maturity, in plot-size samples (0·8 m2/plot). In experiments BC96 and BC97, SF was determined both in plot-size samples and in individual spikes (five spikes per plot), at the beginning of grain filling. In experiment ML07, increasing numbers of individual spikes were sampled at maturity to assess SF. As a result: (1) a significant association (R2=0·78; P<0·001; d.f.=20) was detected between SF determined at the beginning of grain filling and at maturity, and the test of agreement for categorical rating showed that the classification of data into categories of SF was equivalent between methods (P>0·05); (2) when comparing SF determined in large plot-size samples v. in small samples of individual spikes, a good adjustment (R2=0·77; P<0·001; d.f.=6) was also observed, with no significant cultivar×experiment interaction and a good agreement between methods in the classification of data into categories of SF (P>0·05); and (3) increasing sample size from 5 to 40 spikes gradually decreased the average relative standard error of the mean (from 0·034 to 0·012, respectively). In conclusion, wheat SF can be determined in a fairly accurate way by sampling a small group of individual spikes at crop maturity, thereby allowing the evaluation of a large number of treatments in a timely fashion and the screening of breeding material from early generations.

scholarly journals Variation of grain nitrogen content in relation with grain yield in old and modern Spanish wheats grown under a wide range of agronomic conditions in a Mediterranean region

2009 ◽  
Vol 147 (6) ◽  
pp. 657-667 ◽  
Author(s):  
M. M. ACRECHE ◽  
G. A. SLAFER
Keyword(s):  
Nitrogen Content ◽  
Field Experiments ◽  
Dilution Effect ◽  
Grain Filling ◽  
Nitrogen Accumulation ◽  
Grain Number ◽  
Wide Range ◽  
Manipulative Experiments ◽  
Grain Nitrogen ◽  
Source Sink

SUMMARYWheat yield and grain nitrogen concentration (GNC; mg N/g grain) are frequently negatively correlated. In most growing conditions, this is mainly due to a feedback process between GNC and the number of grains/m2. In Mediterranean conditions, breeders may have produced cultivars with conservative grain set. The present study aimed at clarifying the main physiological determinants of grain nitrogen accumulation (GNA) in Mediterranean wheat and to analyse how breeding has affected them. Five field experiments were carried out in north-eastern Spain in the 2005/06 and 2006/07 growing seasons with three cultivars released at different times and an advanced line. Depending on the experiment, source-sink ratios during grain filling were altered by reducing grain number/m2 either through pre-anthesis shading (unshaded control or 0·75 shading only between jointing and anthesis) or by directly trimming the spikes after anthesis and before the onset of the effective grain filling period (un-trimmed control or spikes halved 7–10 days after anthesis). Grain nitrogen content (GN content; mg N/grain) decreased with the year of release of the genotypes. As the number of grains/m2 was also increased by breeding there was a clear dilution effect on the amount of nitrogen allocated to each grain. However, the increase in GN content in old genotypes did not compensate for the loss in grain nitrogen yield (GNY) due to the lower number of grains/m2. GN content of all genotypes increased (increases ranged from 0·13 to 0·40 mg N/grain, depending on experiment and genotype) in response to the post-anthesis spike trimming or pre-anthesis shading. The degree of source-limitation for GNA increased with the year of release of the genotypes (and thus with increases in grain number/m2) from 0·22 (mean of the four manipulative experiments) in the oldest cultivar to 0·51 (mean of the four manipulative experiments) in the most modern line. It was found that final GN content depended strongly on the source-sink ratio established at anthesis between the number of grains set and the amount of nitrogen absorbed at this stage. Thus, Mediterranean wheat breeding that improved yield through increases in grain number/m2 reduced the GN content by diluting a rather limited source of nitrogen into more grains. This dilution effect produced by breeding was further confirmed by the reversal effect produced by grain number/m2 reductions due to either pre-anthesis shading or post-anthesis spike trimming.

Effects of varying nitrogen supply at different stages of the reproductive phase on spikelet and grain production and on grain nitrogen in wheat

1973 ◽  
Vol 24 (5) ◽  
pp. 647 ◽  
Author(s):  
RHM Langer ◽  
FKY Liew
Keyword(s):  
Leaf Area ◽  
Flag Leaf ◽  
Grain Filling ◽  
Solution Culture ◽  
Nitrogen Supply ◽  
Nitrogen Application ◽  
Stage Number ◽  
Leaf Area Duration ◽  
Three Stages ◽  
Grain Nitrogen

Plants of wheat cv. Arawa confined to the main shoot were grown in solution culture in a glasshouse. Nitrogen supply was either high (150 p.p.111.) or low (15 p.p.m.) at three stages of development: between the double-ridge stage and floret initiation, between then and ear emergence, or after ear emergence, giving eight treatment combinations. Spikelet numbers were increased only by raising nitrogen supply at the doubleridge stage. Number of grains per spikelet also responded to treatment during the same period, but was greatest when high nitrogen was given until ear emergence. This response depended on the position of the spikelet within the ear, and the basal and terminal spikelets contributed least when nitrogen supply was low. Individual grain weight responded less to treatment than grain numbers. Nitrogen application had a large effect on leaf area duration, but the grain/leaf ratio (G) was depressed. Since their appeared to be no nitrogen effects on photosynthesis per unit flag leaf area, it is suggested that grain yield was controlled mainly by the capacity of the ear to accept carbohydrate, depending on the number of sites available for grain filling. Percentage grain nitrogen increased with lateness of nitrogen application. However, raising nitrogen supply before ear emergence and then decreasing it again also affected grain nitrogen in the ear, which suggests redistribution during grain filling

Alterations in internal partitioning of carbon in soybean plants in response to nitrogen stress

1984 ◽  
Vol 62 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Thomas W. Rufty Jr. ◽  
C. David Raper Jr. ◽  
Steven C. Huber
Keyword(s):  
Carbon Allocation ◽  
Day Treatment ◽  
Dry Weight ◽  
Nitrogen Supply ◽  
Growth Potential ◽  
Nitrogen Partitioning ◽  
Sink Strength ◽  
Reduced Nitrogen ◽  
Glycine Max L ◽  
Soybean Plants

Alterations in internal partitioning of carbon were evaluated in plants exposed to limited nitrogen supply. Vegetative, nonnodulated soybean plants (Glycine max (L.) Merrill, ‘Ransom’) were grown for 21 days with 1.0 mM[Formula: see text] and then exposed to solutions containing 1.0, 0.1, or 0.0 mM[Formula: see text] for a 25-day treatment period. In nitrogen-limited plants, there were decreases in emergence of new leaves and in the expansion rate and final area at full expansion of individual leaves. As indicated by alterations in accumulation of dry weight, a larger proportion of available carbon in the plant was partitioned to the roots with decreased availability of nitrogen. Partitioning of reduced nitrogen to the root also was increased and, in plants devoid of an external nitrogen supply, considerable redistribution of reduced nitrogen from leaves to the root occurred. The general decrease in growth potential and sink strength for nutrients in leaves of nitrogen-limited plants suggested that factors other than simply availability of nitrogen likely were involved in the restriction of growth in the leaf canopy and the associated increase in carbon allocation to the roots.

The effect of changes of assimilate supply around flowering on grain sink size and yield of maize (Zea mays L.) cultivars of tropical and temperate adaptation

1988 ◽  
Vol 39 (2) ◽  
pp. 153 ◽  
Author(s):  
GK Aluko ◽  
KS Fischer
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Zea Mays L ◽  
Flag Leaf ◽  
Dry Weight ◽  
Grain Filling ◽  
Plant Parts ◽  
Male Inflorescence ◽  
Female Inflorescence ◽  
Sink Size

Two maize (Zea mays L.) cultivars of temperate and one of tropical adaptation were grown in a subtropical (27�s.) environment under favourable conditions of plant population density, water and nutrient supply. The radiation incident to the plant during the period from flag leaf to 10 days after flowering was varied from the control by either shading or temporarily restraining leaves of neighbouring plants. The effects of these changes in assimilate supply, and of the presence of the male inflorescence, on the immediate dry weight of various plant parts and grain sink size, and consequential on dry matter production and grain yield was investigated. The radiation treatments effected small but significant changes in crop growth rate. Shading reduced the dry weight of the ear, and husk of the female inflorescence and male inflorescence (tassel). There were increases due to enhanced radiation. While removal of tassels also enhanced the dry weight of the female inflorescence, there was no evidence that the male inflorescence was a preferred sink for assimilates during this stage of growth.In the temperate cultivars, grain number m-2 was associated with ear dry weight at 10 days after anthesis (r = 0.95**). However, only in the tropical cultivar did the larger grain sink result in an increase in grain yield. Shading reduced grain yield in all cultivars probably because of a reduction in the supply of labile assimilates for grain filling.

scholarly journals Shading effects on the yield of an Argentinian wheat cultivar

1991 ◽  
Vol 116 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. Savin ◽  
G. A. Slafer
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Field Experiments ◽  
Wheat Cultivar ◽  
Dry Weight ◽  
Grain Filling ◽  
Incident Radiation ◽  
Sink Strength ◽  
Before And After ◽  
Shading Effects

SUMMARYShading treatments of 50% of the incident radiation were applied to the semidwarf wheat cultivar Leones INTA before and after anthesis in two field experiments in Argentina in 1987 and 1988. The treatments reduced biological (above-ground dry matter) yield, grain yield and number of grains/m2. Number of grains/m2 was closely and linearly correlated with ear dry weight at anthesis and with the photothermal quotient, calculated from 20 days before to 10 days after anthesis. Grain yield was sink limited, and the shading treatments reduced sink strength. The contribution of preanthesis assimilates to grain yield was smaller in the shaded crops than in the unshaded controls; in unshaded crops, almost 40% of grain yield was contributed by preanthesis assimilates whilst in preanthesis shaded crops this contribution was negligible. The proportion of preanthesis assimilates contributed to the grain was closely related to the decrease in stem dry weight during grain filling. The effects of shading on main stems and tillers were the same.

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