Assessing photosynthetic limitation to grain yield in a field crop

1973 ◽  
Vol 24 (3) ◽  
pp. 297 ◽  
Author(s):  
RM Gifford ◽  
PM Bremner ◽  
DB Jones
Keyword(s):  
Carbon Dioxide ◽  
Grain Yield ◽  
Dry Weight ◽  
Grain Filling ◽  
Kernel Weight ◽  
Yield Component ◽  
Carbon Dioxide Enrichment ◽  
Plant Weight ◽  
Source Limitation ◽  
Different Levels

A method is proposed for assessing the degree to which the availability of photosynthate during grain filling limits the yield of a cereal ('source limitation'). The technique uses shading and carbon dioxide enrichment to alter photosynthesis after anthesis, and may be applied in the field. From only final dry weight determinations, the degree of source limitation of grain yield is quantified on a 0 to 1 scale by relating differences in grain weight to differences in plant weight. For a crop of barley (cv. Resibee) on which the method was tried, the degree of source limitation was about one-half, which suggested that for this particular crop neither the source nor the sink presented an overriding limitation to grain yield. This was so for four stands of the cultivar produced by different levels of shading and carbon dioxide enrichment before anthesis. A yield component analysis indicated that kernel weight was the major component changed by post-anthesis treatments. Pre-anthesis treatments, which also affected grain yield, mainly influenced the numbers of ears produced.

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.

Variation between and within species of rapeseed (Brassica campestris and B. napus) in response to drought stress. II.* Growth and development under natural drought stresses

1978 ◽  
Vol 29 (3) ◽  
pp. 479 ◽  
Author(s):  
RA Richards ◽  
N Thurling
Keyword(s):  
Soil Moisture ◽  
Grain Yield ◽  
Genotypic Variation ◽  
Dry Weight ◽  
Grain Filling ◽  
Moisture Stress ◽  
Sowing Date ◽  
Soil Types ◽  
Dry Matter Accumulation ◽  
Plant Weight

Two rapeseed species and cultivars within each of these species differed significantly with respect to the influence of variation in sowing date on growth, development and yield on two different soil types. Soil moisture stress, particularly after anthesis, was the major environmental factor affecting these processes. Grain yield declined markedly with later sowings in both species, and B. napus, despite its later maturity, was more tolerant of severe soil moisture deficits since its grain yield was consistently higher than B. campestris in the more stressed environments. The major distinguishing feature between species contributing most to this difference in yield was the pattern of dry matter accumulation. In B. campestris most of the dry weight of the plant was accumulated after anthesis when drought was most severe, whereas in B. napus dry weight accumulation occurred before anthesis. This resulted in a greater contribution of reserves accumulated by anthesis to grain-filling in B. napus. Most of the variation in seed yield resulted from differences in sowing dates and soil types. When these environmental effects were excluded, the main determinants of genotypic variation in yield were the numbers of pods and branches and harvest index in both species, growth rate in the post-anthesis phase in B. campestris, and plant weight and root/shoot ratio at anthesis in B. napus. Selection strategies for yield improvement in rapeseed growing in drought-stressed environments are discussed. _____________________ *Part I, Aust. J. Agric. Res., 29: 469 (1978).

scholarly journals Evaluation of Sesame Yield and Yield Component under Different NPS Fertilizer Rates in Western Tigray, Ethiopia

2020 ◽  
pp. 1-7
Author(s):  
Teame Shimgabr ◽  
Negasi Gebereslasie ◽  
Haile Alene ◽  
Welesenbet Haftu ◽  
Nebyu Tsegay
Keyword(s):  
Grain Yield ◽  
Seed Yield ◽  
Field Experiments ◽  
Growth Yield ◽  
Yield Component ◽  
Yield Attributes ◽  
Significant Difference ◽  
Fertilizer Rates ◽  
Different Levels ◽  
Number Of Branches

Field experiments were conducted in three sites of Western Tigray, Ethiopia. The experiments aimed at identifying optimum the rate of the newly introduced NPS fertilizer impact with different levels on growth, yield attributes, yield and economics of sesame in vertisols of Western Tigray at the Humera station, Banat and Kebabo Kafta Humera and Tsegede Wereda’s. The treatments consisted of six levels of NPS 0, 50, 100, 150, 200 and 250 kg ha-1 and one blanket recommendation N and P was applied. The experiment was laid out in an RCBD with three replications. Yield of Sesame and yield related components showed significant difference (p < 0.001) compared to control. Results showed that number of branches plant-1, length of pod bearing zone (cm), plant height (cm), number of capsules plant-1, seeds capsule-1 and seed yield was significant differences at (P< 0.001) Grain yield increases from 444.8 kg ha-1 to 671.9 kg ha-1 as NPS and 444.8 kg ha-1 to 628 kg ha-1 as NP increases from 0 (control) to 100 kg ha-1 NPS and 41 kg N and 46 kg P205 ha-1 respectively. But NPS was not significant with blanket recommendation of N and P (41 kg N and 46 kg P205 ha-1), therefore no need to replace the NP by NPS fertilizer in the study area.

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.

Effect of nitrogen, seeding date and cultivar on oat quality and yield in the eastern Canadian prairies

2004 ◽  
Vol 84 (4) ◽  
pp. 1025-1036 ◽  
Author(s):  
William E. May ◽  
Ramona M. Mohr ◽  
Guy P. Lafond ◽  
Adrian M. Johnston ◽  
F. Craig Stevenson
Keyword(s):  
Grain Yield ◽  
Avena Sativa ◽  
Yield Components ◽  
Seed Quality ◽  
Kernel Weight ◽  
Yield Component ◽  
Human Consumption ◽  
Seeding Date ◽  
N Rates

The proportion of oat (Avena sativa L.) being used for race horses and human consumption has increased over the past 15 yr. The objective of this study was to evaluate the effects of N, seeding date and cultivar on grain yield components, grain yield and grain quality of oat under a direct seeding system. Four N rates, three seeding dates and two cultivars were tested at Indian Head, Melfort, and Canora, SK, and Brandon, MB. Yield was more responsive to increasing N rates from 15 and 80 kg ha-1 when oat was seeded in early May versus early June. Panicles plant-1 was the yield component that accounted for most of the yield increase achieved from increasing rates of N, while kernel weight was the yield component that decreased as the rate of N increased. Physical seed quality decreased (plump seed decreased and thin seed increased) with delayed seeding and greater N fertilizer rates. Nitrogen fertilizer and seeding date had a much larger effect on the quality of CDC Pacer than AC Assiniboia. Combining early seeding, appropriate N fertility and well-adapted cultivars should increase the likelihood of optimizing oat yield and quality necessary for high-value markets. Key words: Avena sativa L., yield components, test weight, lodging, plump seed, thin seed

scholarly journals Barley response to seeding date in central Alberta

2003 ◽  
Vol 83 (2) ◽  
pp. 275-281 ◽  
Author(s):  
P. E. Juskiw ◽  
J. H. Helm
Keyword(s):  
Hordeum Vulgare ◽  
Grain Yield ◽  
Grain Filling ◽  
Kernel Weight ◽  
Seeding Rate ◽  
Hordeum Vulgare L ◽  
Vegetative Period ◽  
Seeding Date ◽  
The Mean ◽  
Grain Filling Period

Seeding date is an important factor influencing productivity of barley (Hordeum vulgare L.). When conditions are conducive to early seeding or result in delayed seeding, producers need to know how cultivars will respond to these seeding situations. In this study, five cultivars (Abee, Harrington, Jackson, Noble and Virden) registered for western Canada were studied for 4 yr (1990 to 1993) when seeded early (late April or early May), in mid-May, in late-May, or late (mid-June) at Lacombe, AB. For all cultivars, early seeding resulted in grain yield advantages of 113 to 134% of the mean site yield, while with late seeding, grain yields were reduced to 54 to 76% of the mean site yield. The reduction in yield was least for Jackson, the earliest maturing cultivar tested. Late seeding reduced the period from sowing to emergence, vegetative period, grain-filling period, time from emergence to physiological maturity, test weight, grain yield, kernel weight, and tillers per plant; and increased plant height and percent thins. Late seeding had no significant effect on phyllochron, stand establishment, scald, lodging, protein content of the grain, kernel number per spike, and spikelet number per spike. Barley responded positively to early seeding in central Alberta, but when seeding was delayed (in this study to mid-June) the early and mid-maturing six-rowed cultivars with short phyllochrons performed better than the two-rowed and late six-rowed cultivars. Key words: Hordeum vulgare L., seeding rate, phenological development, grain quality, grain yield, components

scholarly journals Changes in stem and spike related traits resulting from breeding in Iranian wheat cultivars: associations with grain yield

2017 ◽  
Vol 53 (No. 3) ◽  
pp. 107-113
Author(s):  
M. Joudi ◽  
A. Ahmadi ◽  
V. Mohammadi
Keyword(s):  
Grain Yield ◽  
Selection Criterion ◽  
Dry Weight ◽  
Grain Filling ◽  
Specific Weight ◽  
Indirect Selection ◽  
Wheat Cultivars ◽  
Terminal Drought ◽  
Positive Correlations ◽  
Terminal Drought Stress

This study investigated changes in stem and spike characteristics resulting from breeding in Iranian wheat cultivars, and their relationship with grain yield. Eighty-one wheat cultivars released between 1930 and 2006 were examined under well-watered (WW) and terminal drought stress (DS) conditions in Karaj during 2007–2008 and 2008–2009 and under WW condition at Parsabad in Moghan region during 2010–2011. A genetic improvement over time in stem specific weight (SSW) along with significant positive correlations between this trait and grain yield were found at Karaj under DS conditions and at Parsabad, suggesting that SSW could be used as an indirect selection criterion for yield in these environments. Time-dependent changes in spike dry weight showed that the magnitude of partitioned photoassimilates to the spike during the phase anthesis – 16 days after anthesis (16 DAA) was not changed by breeding. However, during the 16 DAA ‒ maturity phase, modern cultivars had more photoassimilates allocated to the spike than the old ones. This suggests that the sink is more limited during early grain growth than during the end of grain filling. 

Source - sink effects on grain weight of bread wheat, durum wheat, and triticale at different locations

2006 ◽  
Vol 57 (2) ◽  
pp. 227 ◽  
Author(s):  
Daniel F. Calderini ◽  
M. P. Reynolds ◽  
G. A. Slafer
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Bread Wheat ◽  
Grain Filling ◽  
Grain Weight ◽  
The Other ◽  
Field Conditions ◽  
Breeding Strategies ◽  
Source Sink ◽  
Source Limitation

Source limitation during grain filling is important for both management and breeding strategies of grain crops. There is little information on the sensitivity of grain weight of temperate cereals to variations in source–sink ratios, and no studies are available on the comparative behaviour of temperate cereals growing together in the same experiment. The objective of the current study was to evaluate, under field conditions, the response of grain weight to different source–sink ratios during grain filling in high-yielding cultivars of bread wheat, durum wheat, and triticale at 2 contrasting locations. Two experiments were carried out at C. Obregon and El Batan in Mexico. In each location, 6 genotypes (2 bread wheat, 2 durum wheat, 2 triticale) were evaluated. A week after anthesis, 2 source–sink (control and halved spikes) treatments were imposed. Location and genotype significantly (P < 0.01) affected grain yield and components. Significant grain weight increases (P < 0.05) were found only in 2 cases in El Batan. The highest response of 17% was found in triticale, with less than 10% in most of the other genotypes. The effect of genotype and location is discussed.

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