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.

Oil yield components and oil quality of high stearic-high oleic sunflower genotypes as affected by intercepted solar radiation during grain filling

2012 ◽  
Vol 63 (4) ◽  
pp. 330 ◽  
Author(s):  
Roberto D. Martínez ◽  
Natalia G. Izquierdo ◽  
Raúl González Belo ◽  
Luis A. N. Aguirrezábal ◽  
Fernando Andrade ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Yield Components ◽  
Management Practices ◽  
Field Experiments ◽  
Oil Quality ◽  
Grain Filling ◽  
Oil Yield ◽  
Plant Oil ◽  
High Oleic ◽  
Intercepted Solar Radiation

High stearic-high oleic sunflower oil presents high thermal stability. This oil is an alternative to the hydrogenation process which produces trans fatty acids. The effect of intercepted solar radiation (ISR) per plant during grain filling on oil yield components and oil fatty acid composition was investigated in three sunflower high stearic-high oleic genotypes. Three field experiments were conducted and treatments to modify ISR per plant were applied during grain filling: shading, defoliating and thinning plants. Increasing ISR per plant linearly increased grain number per capitulum, weight per grain and in some cases palmitic and stearic acid percentages. In the hybrid, grain oil percentage and oleic acid concentration increased with a decreasing rate, reaching a maximum value at high levels of ISR per plant. Linoleic acid percentage decreased with a decreasing rate, reaching a minimum value at high levels of ISR per plant. Oil yield components presented heterosis. This information contributes to explain the effects of environment on yield and oil quality in high stearic-high oleic genotypes and could be used to design management practices that optimise these traits.

Grain number determination in an old and a modern Mediterranean wheat as affected by pre-anthesis shading

2009 ◽  
Vol 60 (3) ◽  
pp. 271 ◽  
Author(s):  
Martín M. Acreche ◽  
Guillermo Briceño-Félix ◽  
Juan A. Martín Sánchez ◽  
Gustavo A. Slafer
Keyword(s):  
Solar Radiation ◽  
Field Experiments ◽  
Unit Area ◽  
Dry Weight ◽  
Good Method ◽  
Structural Components ◽  
Grain Number ◽  
Growing Period ◽  
Incoming Solar Radiation ◽  
Advanced Line

As the number of grains per unit area has been the main bread wheat (Triticum aestivum) yield determinant affected by breeding, and this variable is highly responsive to pre-anthesis shading, the analysis of the effects of shading on old and modern wheats appears to be a good method to explore how breeding has improved yield. Two field experiments were carried out in a region of Mediterranean Spain with an old cultivar (Aragon 03) and a modern line (advanced line ID-2151) and with 4 shading treatments that reduced by c. 75% the daily incoming solar radiation: unshaded control, shading from jointing to anthesis, shading from jointing to the beginning of booting, and shading from the beginning of booting to anthesis. Grain number per m2 differed between cultivars and was affected by shading. The old cultivar had much fewer grains per spikelet (c. 45%) and slightly fewer spikelets per spike (c. 15%) than the modern line and shading decreased only the number of grains per spikelet in direct proportion to the reduction of the incoming solar radiation, leaving the number of spikes per m2 unaffected by either of the 2 factors. Shading the crop during the entire spike growing period also decreased harvest index (c. 17%), although the reduction in partitioning was not evident at anthesis. As the biomass and spike dry weight at anthesis were similarly and consistently reduced by shading, it seemed that pre-anthesis shading reduced the number of developing florets, with its effects on the number of grains per m2, without major changes in resource allocation among structural components of the spike (rachis, glumes, and awns).

scholarly journals Grain filling parameters in high-yielding ns wheat cultivars

2008 ◽  
pp. 53-58
Author(s):  
Milka Brdar ◽  
Marija Kraljevic-Balalic ◽  
Borislav Kobiljski
Keyword(s):  
Multivariate Analysis ◽  
Nonlinear Regression ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Grain Filling ◽  
Grain Weight ◽  
Cultivar Differences ◽  
Wheat Cultivars ◽  
Estimated Parameters ◽  
Grain Filling Duration

Grain yield of wheat is dependent on grain weight, which is the result of grain filling duration and rate. The study was undertaken to examine the relation between grain weight and rate and duration of grain filling in five high-yielding NS wheat cultivars. Stepwise multivariate analysis of nonlinear regression estimated grain filling parameters was used to examine cultivar differences in grain filling. On the basis of three-year average, the highest grain dry weight had cultivar Renesansa, and the lightest grains were measured for cultivar Evropa 90. Stepwise multivariate analysis indicated that all three nonlinear regression estimated parameters (grain weight, rate and duration of grain filling) were equally important in characterizing the grain filling curves of the cultivars studied, although sequence of their significance varied in different years, which is probably caused by different environmental conditions in three years of experiment.

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.

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. 

scholarly journals MOLECULAR MARKER ANALYSIS OF SPIKE FERTILITY INDEX AND RELATED TRAITS IN A BREAD WHEAT RECOMBINANT INBRED LINE POPULATION

2019 ◽  
Vol 30 (2) ◽  
pp. 7-20
Author(s):  
J.S. Panelo ◽  
M.P. Alonso ◽  
N.E. Mirabella ◽  
A.C. Pontaroli
Keyword(s):  
Molecular Marker ◽  
Field Experiments ◽  
Bulked Segregant Analysis ◽  
Functional Markers ◽  
Grain Number ◽  
Phenotypic Data ◽  
Fertility Index ◽  
Marker Analysis ◽  
Molecular Marker Analysis ◽  
Genomic Regions

Spike fertility index (SF) has been well established as an ecophysiological trait related to grain number per unit area and a promising selection target in wheat breeding programs. Scarce information on the molecular basis of SF is available thus far. In this study, a preliminary molecular marker analysis was carried out in a RIL population derived from the cross between two Argentinean cultivars with contrasting SF to identify candidate genomic regions associated with SF. Twenty-four microsatellites and two functional markers that had been found to co-segregate with SF in a bulked-segregant analysis of the F3 generation of the population were analyzed. Phenotypic data were collected from three field experiments carried out during 2013, 2014 and 2015 growing seasons at Balcarce, Argentina. Two genomic regions associated with SF in chromosomes 5BS and 7AS were detected, which merit further investigation. Key words: selection, genomic regions, grain number, yield, QTL, spike fertility index, fruiting efficiency

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.

scholarly journals Field priming with cytokinins enhances seed viability of wheat after low temperature storage

2021 ◽  
Vol 67 (No. 2) ◽  
pp. 77-84
Author(s):  
Radoslav Chipilski ◽  
Irina Moskova ◽  
Albena Pencheva ◽  
Konstantina Kocheva
Keyword(s):  
Low Temperature ◽  
Field Experiments ◽  
Growth Parameters ◽  
Seed Viability ◽  
Dry Weight ◽  
Grain Filling ◽  
Seedling Vigour ◽  
Cell Membrane Stability ◽  
Low Temperature Storage ◽  
Temperature Storage

Field experiments were conducted with two winter wheat cultivars that were primed with 6-benzylaminopurine (6-BA) or kinetin at the concentration 10 mg/L twice during the grain filling stage. After priming, wheat physiological parameters were measured in the field, and the analysis of yield was performed after harvest. Harvested seeds were subjected to low temperature storage for 12 months at –18 °С simulating conservation conditions in genebanks. In field experiments, treated plants exhibited up to 14% higher productivity, higher fresh and dry weight, and chlorophyll content index of flag leaves. Priming significantly improved germination, seedling vigour and growth parameters. In 5-days-old seedlings developed from low temperature stored seeds of field primed plants, the average accumulation of malondialdehyde and H<sub>2</sub>O<sub>2</sub> was estimated 25% lower, which contributed to higher cell membrane stability. These results correlated positively with growth characteristics of 15-days-old seedlings. The stimulating action of cytokinin priming was more pronounced in the modern cv. Geya-1 compared to the older cv. Sadovo 772 and could be attributed to improved anti-aging mechanism connected with better protection against oxidative damage.  

scholarly journals Genotypic variations for photoassimilates partitioning to the grains during early development of endosperm in wheat: Association with grain weight

Genetika ◽  
2017 ◽  
Vol 49 (1) ◽  
pp. 313-328 ◽  
Author(s):  
Mehdi Joudi
Keyword(s):  
Early Development ◽  
Close Association ◽  
Dry Weight ◽  
Grain Weight ◽  
Time Dependent ◽  
Wheat Cultivars ◽  
Grain Number ◽  
Growing Seasons ◽  
Grain Number Per Spike ◽  
Days After Anthesis

There is little information on genotype variations for photoassimilates partitioning to the grains during early development of endosperm in wheat. Eighty-one wheat cultivars were examined in the Moghan region of Iran during 2010-2011 and 2013-2014 growing seasons. The amount and rate of photoassimilates partitioning to the grains were measured in the tested cultivars during anthesis-16 days after anthesis (DAA) and 16 DAA-maturity phases using time dependent changes in spike dry weight. There were substantial genetic variations in the amount and rate of partitioned photoassimilates to the grains during anthesis-16 DAA and 16 DAA-maturity phases. Part of these variations could be attributed to cultivars differences in anthesis time, spike dry weight at anthesis, and grain number per spike. Taking them into accounts, there were some cultivars but they differed in partitioned photoassimilates toward grains during anthesis-16 DAA and 16 DAA-maturity phases, further supporting the idea that breeding for photoassimilates partitioning during these phases was a possibility. The results yielded for 2013-2014 showed that there is close association between photoassimilates partitioning to the grain during anthesis-16 DAA and individual grain weight. The results suggest that in case wheat breeders could improve photoassimilates partitioning to the grains during anthesis-16 DAA, it would result in increased grain size and weight in the wheat.

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