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

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.

2016 ◽  
Vol 47 (2) ◽  
Author(s):  
Jaddoa & Kadom

A field trial was conducted at Abu-Ghraib Research Station-Agricultural Research Directorate-Ministry of Agriculture during the growing seasons of 2012-2013 and 2013-2014. The objective was to investigate the effect of source-sink Regulation on grain yield  and its companents of five bread wheat cultivars (Triticum aestivum L.). Randomized complete block design with the arrangement of split-plots with three replicates was used. Bread wheat cultivars (Bohooth-22, IPA 99, Abu-Ghraib-3,Al-Fath and Al-Rasheed) occupied the main plots while treatments of source-sink relationship regulation occupied the sub-plots. They included eight treatments: Con. control (Con.), S1 (removal of lamina of the flag leaf of main stem), S2 (removal of laminas of the leaf  beneath the flag leaf), S3 (removal of both lamina of the leaf  and the leaf under flag leaf), S4 (removal of upper third spikelets),S5 (removal of median third spikelets), S6 (removal of lower third spikelets) and S7 (removal all spikelets from one side of spike) . Characteristics of plant height, flag leaf area, spike length, no of spikelet per spike, spike weight, and grain yield and its components were measured and estimated. Results of the present study indicated the followings:  Cultivar (Bohooth-22) gave the highest 1000 grain weight (35.70 and 35.31 g) the highest grain yield (5.467 and 5.148 t.ha-1) in both seasons, respectively compared with Abu-Ghraib3 and Al-Rasheed cultivars which gave lowest grain yield (4.918,4.364, 4.239 and 4.352 t.ha-1) in both seasons, respectively and then less 1000 grain weight (30.15, 32.66, 32.61 and 32.77 g), in both seasons, respectively. Treatment (Con.) i.e no modification of source-sink relationship gave the highest grain yield (5.93 and 5.66 t.ha-1) in both seasons, respectively. Treatments of regulation source (S1 and S3)gave grain yield (4.909, 4.698, 4.621and 4.356 t.ha-1), respectively while (S5) treatment gave the lowest grain yield (4.203 t.ha-1) in the first season and (4.061 t.ha-1) in the second season. This indicates that sink regulation treatment was the most influencial in reducing grain yield than the source regulation treatment, especially, treatment (S5) in both seasons where the  median third of spikelets had been removed due to the reduction of spike growth rate (3.18 and 2.49 g.day-1) in both seasons compared with the (Con) treatment which gave the highest values of spike growth rate (3.91 and 3.12 g.day-1) in both seasons, respectively which resulted in the reduction of dry matter translocation in the (S5) treatment (1.87 and 1.74 g.day -1) and consequently in the reduction of 1000 grain weight (30.09 and 31.199) compared with (34.99 and 37.12 g) in the (Con.) treatment in both seasons, respectively.


2014 ◽  
Vol 65 (2) ◽  
pp. 185 ◽  
Author(s):  
Román A. Serrago ◽  
Daniel J. Miralles

Late foliar diseases (especially leaf rust) reduce assimilate supply during post-anthesis, determining fewer assimilates per grain and thereby inducing grain weight reductions. Although the assimilate reduction hypothesis is the most accepted to explain decreases in grain weight due to late foliar diseases, it has not been clearly established whether those reductions could be completely ascribed to source limitations or whether diminished grain weight could be the consequence of reductions in grain weight potential. The objective of this work was to determine whether grain weight reductions due to leaf rust during grain filling could be associated with source–sink limitations. Two experiments (during 2007 and 2008 growing seasons) including healthy and diseased wheat crops were conducted under field conditions. Source–sink manipulation treatments and grain water content measurements were made to test the source- and sink- limitation hypotheses due to the appearance of late foliar diseases during grain filling. Leaf rust was induced to appear exclusively during grain filling, and in both years, it reduced grain yield and grain weight in both experiments. However, except for distal grains, there were no significant differences between healthy and diseased plots in maximum grain water content, indicating that late foliar diseases did not affect the potential size of the grains. The reserves stored in stems were remobilised to the growing grains in both healthy and diseased crops. However, the reserves remaining at physiological maturity were significantly reduced in diseased crops. Reduction in grain number by trimming the spikes increased the grain weight in diseased but not in healthy crops. Grain weight of trimmed spikes in diseased crops reached similar values to those of healthy crops. These results support the hypothesis that foliar diseases could cause source limitation for grain filling beyond differences in grain weight potential when the crops are severely affected by late foliar diseases such as leaf rust.


2005 ◽  
Vol 56 (1) ◽  
pp. 25 ◽  
Author(s):  
Francesco Giunta ◽  
Rosella Motzo

Comparisons among species can be a valuable approach to identifying traits important for plant breeding. Differences between 2 durum wheat (Duilio and Creso) and 1 triticale (Antares) cultivar have been analysed in a 2-year field trial in Sardinia (Italy), in order to define a more productive durum wheat ideotype for Mediterranean-type environments. The greater grain yield (569 v. 447 g/m2) and the lower protein percentage (9.2 v. 10.6%) of triticale cv. Antares compared with the durum wheat cultivars, at a similar level of biomass produced at heading, were analysed in terms of number of grains per unit surface and rate and duration of dry matter (DM) and nitrogen (N) accumulation, calculated from a logistic curve. When the single grains were considered, Antares showed a lower rate but a longer duration of DM and N accumulation in the more favourable season, resulting in lower DM (40 v. 54 mg) and N (0.7 v. 1.0 mg) contents in the grain. On the other hand, when data were expressed on a per unit surface basis, the greater spike fertility of Antares (53 v. 39 grains per spike) and its longer duration of accumulation, were responsible for similar or even greater amounts of DM and N accumulated in the grains per m2. Growth rate of single grains, although able to explain differences in single grain weight, cannot explain differences in grain weight per m2 and hence in yield, which mainly result from variation in the number of grains per spike. Nitrogen percentage of the grains decreased from the maximum values observed at the beginning of grain filling, until a constant final value attained before the end of DM and N accumulation. Rate is more important than duration in determining the quality characteristics of grains, as higher grain weights and protein percentages correspond to higher rates of DM and N accumulation.


Author(s):  
Ailin Beznec ◽  
Paula Faccio ◽  
Daniel J. Miralles ◽  
Leonor G. Abeledo ◽  
Cecilia Decima Oneto ◽  
...  

Abstract Background The heterologous expression of isopentenyl transferase (IPT) under the transcriptional control of the senescence-associated receptor-like kinase (SARK) promoter delayed cellular senescence and, through it, increased drought tolerance in plants. To evaluate the effect of pSARK::IPT expression in bread wheat, six independent transgenic events were obtained through the biolistic method and evaluated transgene expression, phenology, grain yield and physiological biomass components in plants grown under both drought and well-irrigating conditions. Experiments were performed at different levels: (i) pots and (ii) microplots inside a biosafety greenhouse, as well as under (iii) field conditions. Results Two transgenic events, called TR1 and TR4, outperformed the wild-type control under drought conditions. Transgenic plants showed higher yield under both greenhouse and field conditions, which was positively correlated to grain number (given by more spikes and grains per spike) than wild type. Interestingly, this yield advantage of the transgenic events was observed under both drought and well-watered conditions. Conclusions The results obtained allow us to conclude that the SARK promoter-regulated expression of the IPT gene in bread wheat not only reduced the yield penalty produced by water stress but also led to improved productivity under well-watered conditions.


2000 ◽  
Vol 51 (7) ◽  
pp. 891 ◽  
Author(s):  
D. Villegas ◽  
N. Aparicio ◽  
M.M. Nachit ◽  
J. L. Araus ◽  
C. Royo

The relationships between various morphophysiological traits and yield were studied in durum wheat (Triticum durum Desf.) grown in Mediterranean conditions. Two sets of 22 genotypes were used. One was developed for semi-humid environments (TA-genotypes) and was cultivated in 22 trials around the Mediterranean basin with a mean yield across genotypes and environments of 4925 kg/ha. The other set was developed for drier conditions (CA-genotypes) and was cultivated in 15 trials, with a mean yield of 3501 kg/ha. Morphophysiological traits for each set were evaluated in 2 trials with contrasting water regimes conducted in north-eastern Spain: Lleida-rainfed (LR) and Lleida-irrigation (LI). Two kinds of traits were evaluated: developmental traits, including early vigour, plant height, and phenology (days from planting to heading and to maturity); and traits related to photosynthetic performance such as canopy temperature and chlorophyll content of the flag leaf, both measured during grain filling, and carbon isotope discrimination of mature grains. All the traits, measured in both Lleida trials, were related to the mean yield of the same genotypes across all the sites where they were cultivated. Yield measured at either of the 2 environments at Lleida was a much poorer predictor of genotype differences in mean yield than most of the traits. Nevertheless, the kind of environment where the morphophysiological traits were evaluated affected the performance of these traits as yield predictors. The combination of significant traits measured in the better environment (LI) explained 71% and 55% of genotype variability in yield within TA- and CA-genotypes, respectively, but only 56% and 27% when they were evaluated at LR. On the other hand, growing conditions of the yield trials was the main factor determining the best combination of traits. For TA-genotypes, larger yields were associated with shorter plants and higher carbon isotope discrimination (Δ) of grains, and to a lesser extent with higher early vigour and lower canopy temperature, whereas phenological traits made no contribution to explaining genotype differences in yield. For the CA-genotypes, higher yields were related to an earlier heading date or alternatively to a higher chlorophyll content during grain filling. A higher Δ in mature kernels also seems to be a positive trait.


2016 ◽  
Vol 61 (2) ◽  
pp. 113-125
Author(s):  
Gordana Brankovic ◽  
Dejan Dodig ◽  
Desimir Knezevic ◽  
Vesna Kandic ◽  
Jovan Pavlov

The research was aimed at examining variability, variance components, broadsense heritability (h2), expected genetic advance of thousand grain weight (TGW) and grain number per spike (GNS) of 15 genotypes of bread wheat and 15 genotypes of durum wheat. Field trials were carried out during 2010-2011 and 2011-2012 growing seasons at the three sites: Rimski Sancevi, Zemun Polje and Padinska Skela. Results of this investigation showed that the genetic component of variance (?2 g) was predominant for TGW of bread and durum wheat and for GNS of bread wheat. The genotype ? environment interaction (?2 ge) component of phenotypic variance was 8.72 times higher than ?2 g for GNS of durum wheat and pointed to the greater instability of durum wheat genotypes. h2 was very high (>90%) for TGW and GNS of bread wheat, high for TGW of durum wheat - 87.3% and low for GNS of durum wheat - 39.5%. Considering the high values obtained for h2 - 96.4% and the highest value for expected genetic advance as percent of mean (GAM) - 19.3% for TGW of bread wheat, the success of selection for desired values of this yield component can be anticipated. The success of selection cannot be predicted for GNS of durum wheat due to low values obtained for h2 and GAM of 39.5% and 2.8%, respectively.


1994 ◽  
Vol 45 (7) ◽  
pp. 1337 ◽  
Author(s):  
GA Slafer ◽  
R Savin

Postanthesis green area duration (GAD) has been associated frequently with yield. The senescence pattern of green organs is a major component of GAD. It has been proposed that delayed or accelerated senescence is strongly controlled by environmental conditions and the level of source or sink limitation on grain growth. In particular, it has been generally reported that the removal of reproductive structures delays the senescence process. However, results reporting this effect in wheat are not conclusive. A field experiment was conducted at the experimental station of The University of Melbourne comprising a factorial combination of a semidwarf and a standard-height wheat, and two levels of sink strength. At anthesis, 20 main shoots were tagged and detillered. Ten days after anthesis all the spikelets from one side of 10 tagged ears were removed by hand. The experiment was performed under natural, and 3 h-extended photoperiods from seedling emergence to heading. The photoperiod treatments induced differing grain filling environments and differing plant characteristics at onset of grain filling. Green area senescence was similar for both sink size treatments at any combination of cultivar and grain filling condition, indicating that the dynamics of plant senescence was insensitive to a severe reduction in number of grains per spike. Therefore, GAD was not significantly affected by the reduction in sink strength. The number of grains per spike were reduced to ca. 50% due to trimming. Therefore, source-sink ratio was doubled, but no significant changes in individual grain weight were found. There was no relationship between GAD and individual grain weight, confirming that grain growth in field-grown wheat is not limited by the strength of the source. Alternatively, our results confirmed that field-grown wheat is sink-limited during grain filling and that the likely accumulation of soluble carbohydrates in leaves does not affect the onset or rate of senescence.


Author(s):  
Jyotirmaya Mathan ◽  
Anuradha Singh ◽  
Aashish Ranjan

Abstract The source-sink relationship is key to overall crop performance. Detailed understanding of the factors that determine source-sink dynamics is imperative for the balance of biomass and grain yield in crop plants. We investigated the differences in the source-sink relationship between a cultivated rice Oryza sativa cv. Nipponbare and a wild rice Oryza australiensis that show striking differences in biomass and grain yield. Oryza australiensis, accumulating higher biomass, not only showed higher photosynthesis per unit leaf area but also exported more sucrose from leaves than Nipponbare. However, grain features and sugar levels suggested limited sucrose mobilization to the grains in the wild rice due to vasculature and sucrose transporter functions. Low cell wall invertase activity and high sucrose synthase cleavage activity followed by higher expression of cellulose synthase genes in Oryza australiensis stem utilized photosynthates preferentially for the synthesis of structural carbohydrates, resulting in high biomass. In contrast, the source-sink relationship favored high grain yield in Nipponbare via accumulation of transitory starch in the stem, due to higher expression of starch biosynthetic genes, which is mobilized to panicles at the grain filling stage. Thus, vascular features, sucrose transport, and functions of sugar metabolic enzymes explained the differences in the source-sink relationship between Nipponbare and Oryza australiensis.


2020 ◽  
Vol 12 (14) ◽  
pp. 5610
Author(s):  
Alireza Pour-Aboughadareh ◽  
Reza Mohammadi ◽  
Alireza Etminan ◽  
Lia Shooshtari ◽  
Neda Maleki-Tabrizi ◽  
...  

Durum wheat performance in the Mediterranean climate is limited when water scarcity occurs before and during anthesis. The present research was performed to determine the effect of drought stress on several physiological and agro-morphological traits in 17 durum wheat genotypes under two conditions (control and drought) over two years. The results of analysis of variance indicated that the various durum wheat genotypes responded differently to drought stress. Drought stress significantly reduced the grain filling period, plant height, peduncle length, number of spikes per plot, number of grains per spike, thousand grains weight, grain yield, biomass, and harvest index in all genotypes compared to the control condition. The heatmap-based correlation analysis indicated that grain yield was positively and significantly associated with phenological characters (days to heading, days to physiological maturity, and grain filling period), as well as number of spikes per plant, biomass, and harvest index under drought conditions. The yield-based drought and susceptible indices revealed that stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), and harmonic mean (HM) were positively and significantly correlated with grain yields in both conditions. Based on the average of the sum of ranks across all indices and a three-dimensional plot, two genotypes (G9 and G12) along with the control variety (G1) were identified as the most tolerant genotypes. Among the investigated genotypes, the new breeding genotype G12 showed a high drought tolerance and yield performance under both conditions. Hence, this genotype can be a candidate for further multi-years and locations test as recommended for cultivation under rainfed conditions in arid and semi-arid regions.


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