POTENTIAL NET PHOTOSYNTHESIS IN FLAG LEAVES OF SEVERELY DROUGHT-STRESSED WHEAT CULTIVARS AND ITS RELATIONSHIP TO GRAIN YIELD

1974 ◽  
Vol 54 (4) ◽  
pp. 811-815 ◽  
Author(s):  
R. KAUL
Keyword(s):  
Desiccation Tolerance ◽  
Flag Leaf ◽  
Assimilation Efficiency ◽  
Relative Yield ◽  
Net Photosynthesis ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Wheat Cultivars ◽  
Water Deficits ◽  
Flag Leaves

Six wheat cultivars grown in the field in 1973 showed continuously increasing water deficits which attained severe levels by the end of the season. The relative yield performance of five Triticum aestivum L. cultivars was predictable from the integrated net photosynthetic potential of their flag leaves. Grain productivity of a T. durum L. cultivar, Pelissier, was uniformly underestimated, likely because of poor desiccation tolerance of its flag leaf. It is suggested that Pelissier depended on the longevity of its heavily awned spike for additional grain filling. Results show that photosynthetic desiccation tolerance in severely stressed flag leaves of Pitic 62 ranks above that of Manitou, Cypress, and particularly Selkirk and Pelissier. Glenlea was comparable to Manitou and Cypress in flag leaf assimilation efficiency when subjected to early drought hardening, but exhibited less efficiency when subjected to water deficits late in development.

COMPARATIVE DATA ON THE RATE OF PHOTOSYNTHESIS, RESPIRATION, AND TRANSPIRATION OF DIFFERENT ORGANS IN AWNED AND AWNLESS ISOGENIC LINES OF WHEAT

1972 ◽  
Vol 52 (6) ◽  
pp. 965-971 ◽  
Author(s):  
I. D. TEARE ◽  
J. W. SIJ ◽  
R. P. WALDREN ◽  
S. M. GOLTZ
Keyword(s):  
Flag Leaf ◽  
Wheat Yield ◽  
Net Photosynthesis ◽  
Triticum Aestivum L ◽  
Isogenic Line ◽  
Photosynthetic Rates ◽  
Flag Leaves ◽  
Isogenic Lines ◽  
Respiration Rates ◽  
The Difference

Net photosynthesis, respiration, and transpiration were determined on heads and flag leaves of two isogenic lines of wheat (Triticum aestivum L. em Thell) by measuring the difference in CO2 and water-vapor concentrations between the incoming and outgoing air streams of an open cuvette system. Net photosynthetic rates (mg CO2 dm−2 hr−1) of the awnless, awned, and awned-clipped heads were not significantly different, but the amount of photosynthesis (mg CO2 hr−1) per head was greater for the awned than for the awnless isogenic line. Net photosynthetic rates of the heads were 20–26% of the net photosynthetic rates of the flag leaves. Respiration rates were nearly two times greater for the awnless and awn-clipped heads than for the awned head. Respiration rates of the heads were 1.7 and 3.0 times greater than the respiration rates of the flag leaves of the awned and awnless isogenics, respectively. Transpiration per head was 34 and 43% of the transpiration per flag leaf for awnless and awned isogenics, respectively. Comparing P/T ratios showed that the awnless isogenic head had a 20% greater water-use efficiency than the awned. This study not only confirmed the work of others, by associating awnedness with increased wheat yield, but also showed how the chlorophyll-containing area of the head is related to photosynthesis, respiration, and transpiration.

Elevated CO2 accelerates flag leaf senescence in wheat due to ear photosynthesis which causes greater ear nitrogen sink capacity and ear carbon sink limitation

2009 ◽  
Vol 36 (4) ◽  
pp. 291 ◽  
Author(s):  
Chunwu Zhu ◽  
Jianguo Zhu ◽  
Qing Zeng ◽  
Gang Liu ◽  
Zubing Xie ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Leaf Senescence ◽  
Carbon Sink ◽  
Flag Leaf ◽  
Net Photosynthesis ◽  
Grain Filling ◽  
Flag Leaves ◽  
Sink Capacity ◽  
Sink Limitation ◽  
Grain Nitrogen

It was anticipated that wheat net photosynthesis would rise under elevated CO2, and that this would alter the progress of senescence due to the unbalance of carbohydrates and nitrogen. Our study showed that ear carbon sink was limited, and sugar was accumulated, hexokinase activities and levels of phosphorylated sugar were increased within the flag leaves, grain nitrogen sink capacity was enhanced, and flag leaf senescence was accelerated under elevated CO2. However, if the ear of the main stem was covered, these responses to elevated CO2 were absent, and the senescence of flag leaf was not accelerated by elevated CO2. Thus, it appeared that elevated CO2 accelerated the rate of flag leaf senescence, depending on ear photosynthesis. The ears have far higher enhancement of net photosynthesis than flag leaves, and the role of the flag leaf relative to the ear was declined in supplying C assimilation to grain under elevated CO2. This indicates that as CO2 rises, the grain sink needs the N more than C assimilate from flag leaf, so the declining rates of N% and soluble proteins concentration were markedly accelerated under elevated CO2 conditions. This suggests that, the large increase in ear net photosynthesis accelerated grain filling, accelerated remobilising N within flag leaf as the result of the greater grain nitrogen sink capacity. In addition, as the result of grain carbon sink limitation, it limited the export of flag leaf sucrose and enhanced sugar cycling, which was the signal to accelerate leaf senescence. Hence, elevated CO2 subsequently accelerates senescence of flag leaf.

scholarly journals Effect of Heat Stress on Inter-relationship of Physiological and Biochemical Traits with Grain Yield in Wheat (Triticum aestivum L.)

2020 ◽  
pp. 19-29
Author(s):  
Amrita Kumari ◽  
R. D. Ranjan ◽  
Chandan Roy ◽  
Awadesh Kumar Pal ◽  
S. Kumar
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Flag Leaf ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Seedling Stage ◽  
Biochemical Traits ◽  
Highly Correlated ◽  
Complex Phenomena ◽  
Physiological And Biochemical

Heat stress, particularly the stress appears at the time of flowering to grain filling stages causing severe yield loss in wheat. Heat tolerance is complex phenomena that include adjustment in morphological, physiological and biochemical traits of the crop. Present investigation was carried out to understand the effect of terminal heat stress on different traits of wheat. The experiment was conducted in three dates of sowing as timely sown, late sown and very late sown to expose the crop to heat stress at later stages of the crop growth. Significant genetic variations for all the traits evaluated under three conditions indicated the presence of variability for the traits. Trait association analysis revealed that flag leaf chlorophyll content and MSI at seedling stage; MDA at reproductive stage had direct relationship with grain yield. While under very late sown condition MDA and RWC at seedling stages were found to be highly correlated with grain yield. It indicates that MDA, RWC at seedling stage and days to booting, days to milking plays important role in very late sown condition that can be used as selection criteria in breeding programme.

Water use of some recent bread and durum wheat cultivars in western Canada

2007 ◽  
Vol 87 (2) ◽  
pp. 289-292 ◽  
Author(s):  
H. Wang ◽  
T. N. McCaig ◽  
R. M. DePauw ◽  
J. M. Clarke ◽  
R. Lemke
Keyword(s):  
Triticum Aestivum ◽  
Drought Tolerance ◽  
Soil Water ◽  
Water Use ◽  
Triticum Turgidum ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Western Canada ◽  
Wheat Cultivars ◽  
Use Efficiency

Recently developed cultivars of Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) and Canada Western Amber Durum (CWAD) (Triticum turgidum L. var durum) produced significantly more grain than older cultivars. This production was attributed to higher harvest indices and better water use efficiency. Durum cultivars and CWRS AC Intrepid and AC Barrie extracted relatively more soil water below 55 cm, which may be advantageous in minimizing leaching and related to drought tolerance during grain-filling. Key words: Hexaploid wheat, durum, water use, soil water

A tiller inhibitor gene in wheat and its effect on plant growth

1988 ◽  
Vol 39 (5) ◽  
pp. 749 ◽  
Author(s):  
RA Richards
Keyword(s):  
Flag Leaf ◽  
Weight Ratio ◽  
Recessive Gene ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Late Winter ◽  
Stem Density ◽  
Kernel Number ◽  
Reduced Height ◽  
Made In

A recessive gene that inhibits tillering was identified in a wheat (Triticum aestivum L.) from Israel. The locus for tiller inhibition, designated Tin, is linked to the locus for hairy glume (10 � 3 map units apart) and black awns, and hence is presumed to be on the distal end of chromosome IAS. Such a gene has been proposed as desirable for wheat in both low and high input environments. Serial sowings were made every 21 days between autumn and spring in buckets outdoors with lines differing in tillering. At a harvest at the 4.5 leaf stage, tillering was less in the low tillering lines than in the conventional lines in all sowings, but leaf area and weight per plant were unexpectedly higher. Stunting, which is a characteristic of low tillering lines when temperatures are low and daylength long, became apparent in one of the low tillering lines in sowings made in late winter and spring at a time when daylength was 11.5 h and increasing. In four populations segregating for the tillering trait, low tiller number was associated with a higher harvest index, reduced height, an increased duration of the flag leaf life and of grain filling, a lower leaf to stem weight ratio at maturity, higher specific leaf weight, higher stem density and a higher kernel number per unit stem weight. Traits likely to severely limit crop yield other than stunting were not found.

scholarly journals Cadmium uptake, translocation, and redistribution affect Cd accumulation in grain of common wheat (Triticum aestivum L.) cultivars

2020 ◽  
Author(s):  
Yiran Cheng ◽  
Xu Zhang ◽  
Sha Wang ◽  
Xue Xiao ◽  
Jian Zeng ◽  
...  
Keyword(s):  
Common Wheat ◽  
Translocation Factor ◽  
Triticum Aestivum L ◽  
Wheat Cultivars ◽  
Cd Stress ◽  
Cd Uptake ◽  
Cd Accumulation ◽  
Flag Leaves ◽  
Physiological Processes ◽  
Cd Translocation

Abstract Background To study the cadmium (Cd) accumulation in wheat grain, we evaluated the grain Cd concentrations of 46 common wheat cultivars grown at two sites in Sichuan, China and selected five different grain Cd accumulators (a high-Cd accumulator ZM18, four low-Cd accumulators YM51, YM53, SM969 and CM104) to explore the physiological processes of Cd accumulation in the grain of wheat grown under varying degrees of Cd stress. Results Our results showed that the Cd concentration in grain differed among genotypes. Under low-Cd stress, the grain Cd concentration was correlated with the Cd translocation factor (TF) of roots to grain and all the Cd redistribution factors (RFs). Compared with the ZM18, the cultivars YM53 and SM969 accumulated less Cd in the grain due to low Cd redistribution from lower stems and older leaves to grain. The low-Cd accumulators YM51 and CM104 were due to low Cd transport from roots to grain, and low Cd redistribution from glumes, flag leaves, lower stems, and older leaves to grain. Under high-Cd stress, the ZM18, YM53, and SM969 accumulated significantly more Cd in the grain, root and other tissues than did YM51 and CM104. Correlation analyses showed that the grain Cd concentration of wheat under high Cd stress was positively correlated with the Cd concentration in each tissue and the TFs of roots to grains, rachis, internode 1 and flag leaves. Conclusions Cd translocation directly from roots to grain and Cd redistribution from shoots to grain determines the Cd accumulation in grain of wheat cultivars under low-Cd stress. Cd uptake by root and then synchronously transported to new shoots determined the differences of Cd accumulation in the grain of wheat cultivars under high Cd stress.

scholarly journals GENETIC DIVERSITY FOR HEAT TOLERANCE TRAITS IN SPRING WHEAT (Triticum aestivum L.)

2012 ◽  
Vol 25 (2) ◽  
pp. 15-23
Author(s):  
A. A. Khan ◽  
M. Mahbubur Rahman ◽  
M. F. Amin ◽  
M. K. Alam ◽  
M. A. Alam
Keyword(s):  
Genetic Diversity ◽  
Heat Tolerance ◽  
Spring Wheat ◽  
Genetic Divergence ◽  
Flag Leaf ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Cluster Distance ◽  
Heat Tolerant ◽  
Late Sowing

The present investigation was undertaken with the objective to identify the extent of genetic diversity for traits related to heat tolerance among 25 currently available spring wheat genotypes under late sowing condition during the cropping season 2009-2010. All genotypes were distributed into five clusters showing considerable genetic divergence for most of the heat tolerant traits under study. The role of grain filling rate and biomass production in both the vectors had the highest contribution to genetic divergence. The positive values of both the vectors for flag leaf senescence, ground coverage, spikes number, 1000-grain weight, grain yield (g m-2) and harvest index indicating high contribution of these traits towards the divergence among 25 genotypes of wheat. Three pair of clusters, viz. I & II, I & III and I & V can be considered for obtaining more heterotic progeny as the genetic distance between these clusters were larger. Considering yield performances, cluster distance and cluster mean the genotype G-22 from cluster I and genotype G-14 from cluster IV may be considered better parents for further breeding of heat tolerance as they showed maximum divergence and high degree of tolerance to heat under late sowing condition. Moreover, the genotype G-22 could be exploited for direct release as a heat tolerant variety after testing under wider range of environments.DOI: http://dx.doi.org/10.3329/bjpbg.v25i2.18663

scholarly journals Interaksi Genetik x Lingkungan dan Variabilitas Genetik Galur Gandum Introduksi (Triticum aestivum L.) di Agroekosistem Tropika

2016 ◽  
Vol 10 (3) ◽  
pp. 93 ◽  
Author(s):  
Amin Nur ◽  
Muh. Azrai ◽  
Trikoesoemaningtyas Trikoesoemaningtyas
Keyword(s):  
Genetic Variability ◽  
Chlorophyll A ◽  
Flag Leaf ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Yield Component ◽  
Plant Weight ◽  
Seed Head ◽  
High Heritability ◽  
Wheat Lines

<p>The<br />focus of wheat research in Indonesia is to obtained new<br />potential wheat lines that are adapted to low-mid elevation<br />and heat tolerant. This study was aimed to obtain<br />information on the effect of interaction of season x line x<br />location and genetic variability of wheat lines in tropical<br />agroecosystem. This study was conducted at the Seameo-<br />Biotrop (&lt;400 masl) and Indonesian Ornamental Crops<br />Research Institute-Cipanas (&gt;1,000 masl) experimental field<br />for two seasons. The results showed that there was an effect<br />of interaction of season x line x location on plant height,<br />days to flowering, number of spikelet and floret, seed/head<br />weight, rate of grain filling, yield, flag leaf width, stomata<br />density, chlorophyll b, and leaf greenness. Meanwhile<br />several characters were only influenced by the interaction of<br />line x location, they were yield component characters, ie.<br />empty floret percentage, number of seed/ head, 1,000 seed<br />weight, number of head/m2 and seed/plant weight. Seven<br />characters were not influenced by interaction of neither<br />season x line x environment nor line x location, they were<br />number of productive tillers, head length, number of<br />seed/head, chlorophyll a, ratio of chlorophyll a/b, total<br />chlorophyll, and leaf thickness. The characters that have<br />high heritability and wide genetic variability for the two<br />analysis models were the number of spikelet.</p>

scholarly journals Contrasting response of biomass and grain yield to severe drought in Cappelle Desprez and Plainsman V wheat cultivars

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1708 ◽  
Author(s):  
Kenny Paul ◽  
János Pauk ◽  
Zsuzsanna Deák ◽  
László Sass ◽  
Imre Vass
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Electron Transport Rate ◽  
Biomass Accumulation ◽  
Grain Filling ◽  
Photosynthetic Parameters ◽  
Wheat Cultivars ◽  
Flag Leaves ◽  
Use Efficiency ◽  
Grain Filling Period

We report a case study of natural variations and correlations of some photosynthetic parameters, green biomass and grain yield in Cappelle Desprez and Plainsman V winter wheat (Triticum aestivumL.) cultivars, which are classified as being drought sensitive and tolerant, respectively. We monitored biomass accumulation from secondary leaves in the vegetative phase and grain yield from flag leaves in the grain filling period. Interestingly, we observed higher biomass production, but lower grain yield stability in the sensitive Cappelle cultivar, as compared to the tolerant Plainsman cv. Higher biomass production in the sensitive variety was correlated with enhanced water-use efficiency. Increased cyclic electron flow around PSI was also observed in the Cappelle cv. under drought stress as shown by light intensity dependence of the ratio of maximal quantum yields of Photosystem I and Photosystem II, as well by the plot of the Photosystem I electron transport rate as a function of Photosystem II electron transport rate. Higher CO2uptake rate in flag leaves of the drought-stressed Plainsman cv. during grain filling period correlates well with its higher grain yield and prolonged transpiration rate through spikes. The increase in drought factor (DFI) and performance (PI) indices calculated from variable chlorophyll fluorescence parameters of secondary leaves also showed correlation with higher biomass in the Cappelle cultivar during the biomass accumulation period. However, during the grain filling period, DFI and PI parameters of the flag leaves were higher in the tolerant Plainsman V cultivar and showed correlation with grain yield stability. Our results suggest that overall biomass and grain yield may respond differentially to drought stress in different wheat cultivars and therefore phenotyping for green biomass cannot be used as a general approach to predict grain yield. We also conclude that photosynthetic efficiency of flag and secondary leaves is correlated with grain yield and green biomass, respectively. In addition, secondary trait associated mechanisms like delayed senescence and higher water-use efficiency also contribute to biomass stability. Our studies further prove that photosynthetic parameters could be used to characterize environmental stress responses.

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