Partitioning of assimilates to deeper roots is associated with cooler canopies and increased yield under drought in wheat

Dehydration avoidance through cooler canopy temperature (CT) has been shown to explain over 60% yield variation in a random progeny derived from a Seri/Babax cross. A near ‘isomorphic’ subset of Seri/Babax progeny and parents encompassing a restricted range of height and phenology were used for detailed characterisation of drought-adaptive trait expression under contrasting water regimes. Under drought, five of the six progeny out yielded the best parent Babax by up to 35%. The main physiological attributes associated with drought adaptation were increased root dry weight at depth, transpiration rate – evidenced by grain carbon isotope discrimination (Δ13C) – grain filling duration and decreased CT during grain filling. Furthermore, increased root mass at depth was associated with reduced levels of stem water soluble carbohydrates (WSC) when comparing genotypes. It is concluded that differences in rooting depth expressed among iso-morphic wheat sister lines explains superior adaptation to drought. These effects can be detected in season using remote sensing. In addition, the data suggest that accumulation of stem carbohydrates and deep rooting may be two alternative strategies for adapting to drought stress, the latter being beneficial where water is available at depth.

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Genotypic variation in water-soluble carbohydrate accumulation in wheat

Functional Plant Biology ◽

10.1071/fp06062 ◽

2006 ◽

Vol 33 (9) ◽

pp. 799 ◽

Cited By ~ 125

Author(s):

Sari A. Ruuska ◽

Greg J. Rebetzke ◽

Anthony F. van Herwaarden ◽

Richard A. Richards ◽

Neil A. Fettell ◽

...

Keyword(s):

Genotypic Variation ◽

Dry Weight ◽

Grain Filling ◽

Water Soluble ◽

Soluble Carbohydrates ◽

Soluble Carbohydrate ◽

Broad Sense Heritability ◽

Carbohydrate Accumulation ◽

Sequential Mechanism ◽

Water Soluble Carbohydrate

The water-soluble carbohydrate (WSC) that accumulates in the stems of wheat during growth can be an important contributor to grain filling, particularly under conditions when assimilation is limited, such as during end-of-season drought. WSC concentration was measured at anthesis across a diverse set of wheat genotypes over multiple environments. Environmental differences in WSC concentration were large (means for the set ranging between 108 and 203 mg g–1 dry weight), and there were significant and repeatable differences in WSC accumulation among genotypes (means ranging from 112 to 213 mg g–1 dry weight averaged across environments), associated with large broad-sense heritability (H = 0.90 ± 0.12). These results suggest that breeding for high WSC should be possible in wheat. The composition of the WSC, examined in selected genotypes, indicated that the variation in total WSC was attributed mainly to variation in the fructan component, with the other major soluble carbohydrates, sucrose and hexose, varying less. The degree of polymerisation (DP) of fructo-oligosaccharides was up to ~13 in samples where higher levels of WSC were accumulated, owing either to genotype or environment, but the higher DP components (DP > 6) were decreased in samples of lower total WSC. The results are consistent with fructan biosynthesis occurring via a sequential mechanism that is dependent on the availability of sucrose, and differences in WSC contents of genotypes are unlikely to be due to major mechanistic differences.

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Genetic Dissection of Stem Water-Soluble Carbohydrates and Agronomic Traits in Wheat under Different Water Regimes

Journal of Agricultural Science ◽

10.5539/jas.v9n3p42 ◽

2017 ◽

Vol 9 (3) ◽

pp. 42 ◽

Cited By ~ 3

Author(s):

Khan Nadia ◽

Xiaoping Chang ◽

Ruilian Jing

Keyword(s):

Agronomic Traits ◽

Phenotypic Variability ◽

Grain Filling ◽

Wheat Breeding ◽

Water Soluble ◽

Soluble Carbohydrates ◽

Growth Stages ◽

Water Regimes ◽

Water Soluble Carbohydrates ◽

Stem Water

Drought is a major environmental stress threatening wheat (Triticum aestivum L.) productivity worldwide. Although drought impedes wheat performance at all growth stages, it is more critical during the flowering and grain-filling phases and results in substantial yield losses. In this context, stem water-soluble carbohydrates (SWSC) were dissected at flowering and grain filling stages under drought stress (DS) and well-watered (WW) conditions using a population consisted of 116 wheat accessions in this research. The main goal was to dissect the genetic basis of water-soluble carbohydrates and the agronomic traits using association mapping approach and identify linked molecular markers. The results showed significant and positive correlations for stem water-soluble carbohydrates at grain filling (SWSCG) with accumulating efficiency of stem water-soluble carbohydrates (AESWSC) and grain filling efficiency at the late stage (GFEL). The accumulating and grain filling efficiency at grain filling stage could play an important role for SWSC especially under DS condition. Four favorable alleles for plant height (PH) and grain yield (GY) were identified in two water environments. Xbarc78-4A163and Xbarc78-4A155 were variant alleles for PH which were identified in both water regimes. Whereas Xwmc25-2D151 and Xgwm165-4B191 positively linked with GY in WW. Although Xwmc420-4A121and Xwmc112-2D215 were alleles for stem water-soluble carbohydrates at flowering (SWSCF) and SWSCG in DS but the frequency were < 5% so they were considered as rare alleles. These SSR markers which explained significant level of phenotypic variability for chosen traits could be used for selection of genotypes in wheat breeding programs through marker-assisted selection.

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BIPLOT ANALYSIS FOR IDENTIFICATION OF SUPERIOR GENOTYPES IN A RECOMBINANT INBRED POPULATION OF WHEAT UNDER RAINFED CONDITIONS

Journal of Experimental Biology and Agricultural Sciences ◽

10.18006/2021.9(5).598.609 ◽

2021 ◽

Vol 9 (5) ◽

pp. 598-609

Author(s):

Ashutosh Srivastava ◽

◽

Puja Srivastava ◽

R S Sarlach ◽

Mayank Anand Gururani ◽

...

Keyword(s):

Canopy Temperature ◽

Grain Filling ◽

Water Soluble ◽

Physiological Traits ◽

Soluble Carbohydrates ◽

Biplot Analysis ◽

Water Soluble Carbohydrates ◽

Grain Filling Period ◽

Peduncle Length ◽

Ideal Genotype

Physiological traits of wheat genotypes and their trait relation to drought conditions are important to identify the genotype in target environments. Thus, genotype selection should be based on multiple physiological traits in variable environments within the target region. This study was conducted at Punjab Agricultural University during rabi crop seasons 2012-13 and 2013-14 to study the recombinant inbred lines (RILs) of wheat genotypes derived from traditional landraces and modern cultivars (C518/2*PBW343) based on various morpho-physiological traits. A total of 175 RILs were selected for this study based on various tolerance indices. The genotype by trait (GT) biplot analysis was applied to data from seven high-yielding RILs grown under irrigated (E1) and rainfed environments (E2). The GGE biplot explained 100% of the total variation for chlorophyll content, grain filling period, peduncle length, water-soluble carbohydrates, grain number, grain yield, and 95.1% for canopy temperature, 94.9% for thousand-grain weight. GT-biplots indicated that the relationships among the studied traits were not consistent across environments, but they facilitated visual genotype comparisons and selection in each environment. RIL 84 and RIL108 were close to the average environment (ideal genotype) for all traits studied except chlorophyll content. A well-performing genotype with great environmental stability is called an "ideal genotype. Among all entries, these genotypes performed well. Therefore, among the traits studied, grain filling period, peduncle length, canopy temperature, water soluble carbohydrates, and 1000 grain weight contributed to grain yield under a stress environment. Furthermore, it may be used as a donor material in breeding programs and QTLs mapping.

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Grain filling parameters in high-yielding ns wheat cultivars

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn0814053b ◽

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.

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Predictability of wheat growth and yield in light-limited conditions

The Journal of Agricultural Science ◽

10.1017/s0021859606006678 ◽

2007 ◽

Vol 145 (1) ◽

pp. 63-79 ◽

Cited By ~ 42

Author(s):

F. D. BEED ◽

N. D. PAVELEY ◽

R. SYLVESTER-BRADLEY

Keyword(s):

Solar Radiation ◽

Grain Yield ◽

Incident Light ◽

Dry Weight ◽

Water Soluble ◽

Growth And Yield ◽

Soluble Carbohydrates ◽

Total Solar Radiation ◽

Shoot Dry Weight ◽

Source And Sink

In seeking better predictions of grain yield under light-limited conditions, shading was applied to field-grown winter wheat cv. Slejpner during each of five consecutive phases (canopy expansion, ear expansion, pre-flowering, grain expansion and grain filling). Absolute measures were taken of solar radiation and its effects on growth in three seasons, at a site where water and nutrient supplies were not limiting. Replicate mobile shades automatically occluded 0·80 of incident light when mean total solar radiation exceeded 250 J/m2 per s. Mean effects over seasons of shading on incident total solar radiation were −296, −139, −78, −157 and −357 MJ/m2 for the five phases respectively, and corresponding effects on shoot dry weight were −236, −184, −58, −122 and −105 g/m2. Estimated efficiency of radiation use after flowering was 1·2 g/MJ unshaded, tending to increase with shading. Shading in all phases reduced grain dry matter yield: mean effects over seasons were −106, −64, −61, −93 and −281 g/m2 for the five consecutive shading periods. Shading from GS31–39 increased mean maximum area of the two top leaves from 2700 to 3100 mm2 per leaf but, with fewer stems, canopy size remained unaffected. This and the next shading, from GS39–55, reduced specific leaf weight from 42 g/m2 by 4 and 3 g/m2 respectively, but effects on shoot dry weight were largely due to stem and ear. By flowering, stem weights, and especially their reserves of water-soluble carbohydrates, had partially recovered. Effects on yield of shading from GS31–39 were explained by a reduction in grains/m2 of 3070 from 26109. Shading from GS39–55 reduced grains/m2 by 4211 due to fewer grains per ear, whilst mean weight per grain increased in compensation. Shading from GS55–61 decreased grains/ear by 2·5. Shading from GS61–71 decreased ear growth and reduced stem weight, and at harvest resulted in 4·3 less grains/ear. Effects of the final shading from GS71–87 were fully explained by a reduction in mean dry weight/grain of 10·3 mg. Except for shading from GS71–87, source- and sink-based explanations of grain yield both proved feasible, within the precision of the measurements. Constraints to accurate comparison of source- and sink-based approaches are identified, and the implications for yield forecasting are discussed.

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Truncation of grain filling in wheat (Triticum aestivum) triggered by brief heat stress during early grain filling: association with senescence responses and reductions in stem reserves

Functional Plant Biology ◽

10.1071/fp15384 ◽

2016 ◽

Vol 43 (10) ◽

pp. 919 ◽

Cited By ~ 13

Author(s):

Hamid Shirdelmoghanloo ◽

Daniel Cozzolino ◽

Iman Lohraseb ◽

Nicholas C. Collins

Keyword(s):

Triticum Aestivum ◽

Grain Size ◽

Heat Stress ◽

Heat Waves ◽

Flag Leaf ◽

Grain Filling ◽

Water Soluble ◽

Grain Weight ◽

Soluble Carbohydrates ◽

Stem Reserves

Short heat waves during grain filling can reduce grain size and consequently yield in wheat (Triticum aestivum L.). Grain weight responses to heat represent the net outcome of reduced photosynthesis, increased mobilisation of stem reserves (water-soluble carbohydrates, WSC) and accelerated senescence in the grain. To compare their relative roles in grain weight responses under heat, these characteristics were monitored in nine wheat genotypes subjected to a brief heat stress at early grain filling (37°C maximum for 3 days at 10 days after anthesis). Compared with the five tolerant varieties, the four susceptible varieties showed greater heat-triggered reductions in final grain weight, grain filling duration, flag leaf chla and chlb content, stem WSC and PSII functionality (Fv/Fm). Despite the potential for reductions in sugar supply to the developing grains, there was little effect of heat on grain filling rate, suggesting that grain size effects of heat may have instead been driven by premature senescence in the grain. Extreme senescence responses potentially masked stem WSC contributions to grain weight stability. Based on these findings, limiting heat-triggered senescence in the grain may provide an appropriate focus for improving heat tolerance in wheat.

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Time of pruning affects fruit abscission, stem carbohydrates and yield of macadamia

Functional Plant Biology ◽

10.1071/fp11254 ◽

2012 ◽

Vol 39 (6) ◽

pp. 481 ◽

Cited By ~ 14

Author(s):

Lisa McFadyen ◽

David Robertson ◽

Margaret Sedgley ◽

Paul Kristiansen ◽

Trevor Olesen

Keyword(s):

Fruit Set ◽

Photosynthetic Capacity ◽

Water Soluble ◽

Soluble Carbohydrates ◽

Carbon Limitation ◽

Yield Losses ◽

Fruit Abscission ◽

Macadamia Integrifolia ◽

Water Soluble Carbohydrates ◽

Stem Water

Macadamia (Macadamia integrifolia Maiden and Betche, M. tetraphylla Johnson and hybrids) orchards in Australia are typically hedged around anthesis (September). Such hedging reduces yields, largely through competition for carbohydrates between early fruit set and the post-pruning vegetative flush, but also through a reduction in photosynthetic capacity caused by the loss of canopy. We examined whether hedging at other times might mitigate yield losses. Hedging time was found to affect yields across four cultivars: ‘A4’, ‘A38’, ‘344’ and ‘816’. Yield losses were lower for trees hedged in November–December than for trees hedged in September. Yields for trees hedged in June were higher than for trees hedged in September in one experiment, but were similar in a second experiment. Yield losses for September and October hedging were similar. Hedging time changed the pattern of fluctuations in stem water-soluble carbohydrates (WSC). WSC declined shortly after hedging in September, October or November, and the declines preceded increases in fruit abscission relative to unpruned control trees. The increase in fruit abscission was less pronounced for the trees hedged in November, consistent with the idea that fruit become less sensitive to carbon limitation as they mature.

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