Genotypic variation in carbon fixation, δ13C fractionation and grain yield in seven wheat cultivars grown under well-watered conditions

2017 ◽  
Vol 44 (8) ◽  
pp. 809
Author(s):  
Kushal Kumar Baruah ◽  
Ashmita Bharali ◽  
Aninda Mazumdar ◽  
Gulshan Jha

Biotic carbon (C) sequestration is currently being considered as a viable option for mitigating atmospheric carbon dioxide (CO2) emission, in which photosynthesis plays a significant role. A field experiment was conducted between 2013 and 2015 to investigate the efficiency of seven modern wheat varieties for CO2 fixation, C partitioning, δ13C fractionation in the leaves, and grain yield. A strong correlation between flag leaf photosynthesis and stomatal density (r = 0.891) was detected. Photosynthetic efficiency was highest in the variety WH-1021 (28.93 µmol m–2 s–1). Grain yield was influenced by biomass accumulation in the heads and these were significantly correlated (r = 0.530). Our results show that upregulated biomass partitioning to the developing kernels of wheat was inversely proportional to biomass accumulation in the roots, and led to a higher grain yield. These results led us to conclude that identification of a wheat genotype like WH-1021 followed by WH-1080 and WH-711, with higher isotopic discrimination in the flag leaves, stomatal densities, water use and photosynthetic efficiencies along with higher grain yield, can contribute to sustainable agriculture in future climate change situation in India. A yield increment of 9–48% was recorded in WH-1021 over other six tested wheat varieties.

1986 ◽  
Vol 66 (3) ◽  
pp. 503-508 ◽  
Author(s):  
I. Ma. Martin del Molino ◽  
M. Ulloa ◽  
R. Martinez-Carrasco ◽  
P. Perez

1971 ◽  
Vol 22 (1) ◽  
pp. 39 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson

The relative contributions of different photosynthetic sites to the filling of the grain in grain sorghum (Sorghum vulgare cv. Brolga) were estimated by measuring the 14C in the grain after exposing various leaves and the head to radioactive carbon dioxide. Methods for preventing photosynthesis were also used. Of the grain yield, 93% was due to assimilation by the head and upper four leaves. The head contribution of 18 % was due equally to direct assimilation of atmospheric carbon dioxide and to reassimilation of carbon dioxide released within the grain by respiration of material translocated from the leaves. The remaining 75 % was equally assimilated by the upper four leaves, the flag leaf being the most efficient contributor per unit area and the third uppermost leaf the least efficient. The percentage contributions to the grain by the flag leaf and fourth leaf, estimated from the decrease in grain yield when they were shaded, agreed closely with the estimates obtained by using 14CO2.


1984 ◽  
Vol 64 (1) ◽  
pp. 113-118 ◽  
Author(s):  
I. AGUILAR-M. ◽  
L. A. HUNT

Several experiments were conducted with winter wheat (Triticum aestivum L. em. Thell.) during 1978 and 1979 to characterize genotypic variation in some physiological and morphological traits, and to evaluate the magnitude of the relationships between grain yield and the various traits studied. Straw weights of cultivars grown in Eastern Canada were similar to, and harvest indices generally lower than, those reported for high yielding varieties from other countries. Highest grain weights were also lower than the upper values recorded for some cultivars in the U.K. and Mexico, and were little affected by spikelet removal in most cases. All experiments were consistent in showing highly significant correlations between grain yield and grains per square metre, straw weight, harvest index, spikes per square metre, and flag leaf area index, and significant correlations between grain yield and grain weight. Diffusive resistance of the adaxial surface of the flag leaves differed between genotypes, but correlations between diffusive resistance and yield were low and nonsignificant in all cases, with the exception of the preanthesis period in one experiment.Key words: Wheat (winter), Triticum aestivum L. em. Thell., yield, physiological-morphological traits.


1973 ◽  
Vol 21 (4) ◽  
pp. 282-296
Author(s):  
J.H.J. Spiertz

Wheat cv. Juliana (culm length 117 cm), Manella (82 cm), Lely (80 cm), Mex-cross (69 cm) and Gaines (79 cm) were sprayed twice before flowering with 2 kg maneb/ha and twice after flowering with 1 kg benomyl/ha. Combined treatment greatly delayed the spread of Septoria tritici and S. nodorum in the crop, the flag leaf remained green longer, the grain filling period was lengthened, and the growth rate of the grain between the milk stage and the dough stage was increased from 204 to 230 kg/ha day; effects were greater in the susceptible cultivars Lely and Gaines. Increases in grain yield were 14, 23, 32, 16 and 42% for the 5 cultivars, respectively. The green area of the flag leaf accounted for 85% of the variance in grain yield. The degree of disease infection was not significantly correlated with culm length or amount of leaf area. ADDITIONAL ABSTRACT: Spraying with maneb at 2 kg/ha twice before flowering and with benomyl at 1 kg/ha twice after flowering greatly delayed the spread of Septoria tritici and S. [Leptosphaeria] nodorum and increased yields, particularly in the 2 susceptible cvs. (Abstract retrieved from CAB Abstracts by CABI’s permission)


1994 ◽  
Vol 21 (6) ◽  
pp. 717 ◽  
Author(s):  
MP Reynolds ◽  
M Balota ◽  
MIB Delgado ◽  
I Amani ◽  
RA Fischer

Sixteen spring wheat genotypes were grown under hot, irrigated, low latitude conditions, during the 1990-1991 and 1991-1992 winter cropping cycles in Mexico, Egypt, India and the Sudan, and in the 1990 and 1991 winter cycles in Brazil. The genotypes were chosen to represent a range of genetlc diversity within modem wheat varieties. In addition to grain yield, in Mexico a number of morphological and physiological traits were measured throughout the growing season on two sowing dates (December and February), to evaluate their correlation with yield in the other countries. The morphological traits - above-ground biomass at maturity, grains m-2, days to anthesis and days to maturity - measured on both sowing dates in Mexico showed generally significant correlations with yields measured at the other sites. Moreover, ground-cover estimates early in establishment, and at anthesis, also showed some association with performance at these sites, but only when measured on the hotter, February sowing date in Mexico. Membrane thermostability (MT), measured on field-acclimated flag leaves showed generally significant correlations with performance at all sites, and with MT measurements made on heat- acclimated seedlings of the same genotypes grown in growth chambers. Flag-leaf photosynthesis measured at booting, anthesis and during grain filling on both sowing dates, was generally significantly correlated with grain yield at all sites, as was rate of loss of leaf chlorophyll content during grain filling. Stomatal conductance was also significantly correlated with performance at all three stages. Canopy temperature depression (CTD) measured with an infrared thermometer was significantly positively correlated with performance at the international sites when measured between 1200 and 1600 hours, after full canopy establishment. The correlation of CTD with yield was not affected by the irrigation status of the crop under well-watered conditions. The possible use of these traits in selection for yield under hot conditions is discussed.


1999 ◽  
Vol 132 (1) ◽  
pp. 23-30 ◽  
Author(s):  
J. IQBAL ◽  
D. WRIGHT

Three pot experiments were performed at the University of Wales, Bangor, Gwynedd, UK during 1993 to determine if differences in the competitive ability of three annual weeds (Chenopodium album L., Sinapis arvensis L. and Phalaris minor Retz.) were related to their relative effects on leaf growth, gas exchange and nitrogen uptake of spring wheat (cv. Alexandria). In all experiments, wheat density (316 plants m−2) was similar to that in a commercial crop and five weed density treatments (between 0 and 600 plants m−2) were tested. Measurements of gas exchange were made on fully expanded, attached wheat flag leaves on four occasions between emergence and complete senescence in the control and highest weed density treatments. High weed density resulted in a lowering of net photosynthetic rate due to stomatal and non-stomatal factors. Lamina area and stomatal density of wheat flag leaves were decreased, and specific leaf area was increased by weed competition, but the effects on these variables were smaller than on net photosynthesis. Weed density did not affect wheat plant height, but dry weight, grain yield and total N-uptake were decreased with an increase in density of all weed species. The rank order of competitive ability of the species (C. album>P. minor>S. arvensis) was unaffected by weed density and was the same irrespective of whether it was based on the % decreases in wheat grain yield or in total plant dry weight. Averaged over the four measurements made during the grain-filling period there were only small differences between the weed species in their effects on net photosynthetic rate. However, when these were combined with effects on flag leaf area, there were larger differences in calculated net photosynthetic productivity, which were related to differences in the effects of weeds on grain yield. Differences in the competitive ability of weeds were not related to differences in their effects on wheat flag leaf lamina area, specific leaf area, stomatal density or total nitrogen uptake. Differences in competitive ability between weed species were not related to differences in weed plant height, dry weight or nitrogen uptake. It was concluded that the observed effects of weeds on wheat were due either to shading, or to competition for a nutrient other than nitrogen.


1976 ◽  
Vol 12 (4) ◽  
pp. 411-415 ◽  
Author(s):  
A. Rehman Chowdhry ◽  
M. Saleem ◽  
Khurshid Alam

SUMMARYPhenotypic correlation coefficients of flag leaf blade length, breadth and sheath length with plant height, grain yield and its components were computed in four wheat varieties and their ten F2 crosses. Flag leaf sheath length was positively related to plant height, grain yield and its components in almost all the populations, but little or no such relation occurred with flag leaf blade length and breadth in most cases. The data suggested the possibility of selecting plants with longer flag leaf sheaths, with obvious yield advantage.


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