Level of activity of nitrate reductase at the seedling stage as a predictor of grain nitrogen yield in wheat (Triticum aestivum L.)

1977 ◽  
Vol 28 (1) ◽  
pp. 1 ◽  
Author(s):  
MJ Dalling ◽  
RH Loyn

The yield of grain nitrogen of 24 wheat cultivars grown in the field was found to be related to the activity of the enzyme nitrate reductase (EC1.6.6.1) in the first vegetative leaf of 21-day-old plants grown in a controlled environment. It was concluded that a cultivar's potential for yielding grain nitrogen could be predicted from the activity of nitrate reductase at the seedling stage. This could enable the plant breeder to identify, early in the selection program, lines worth keeping for more advanced testing. Harvest index for nitrogen varied considerably between cultivars, but was usually largest in cultivars with large yields of grain nitrogen. Improvement in harvest index for nitrogen should go some way towards breaking the inverse relation between grain yield and grain nitrogen percentage in plants grown on a limited supply of soil nitrogen.

1988 ◽  
Vol 68 (2) ◽  
pp. 311-322 ◽  
Author(s):  
PATRICK M. McMULLAN ◽  
PETER B. E. McVETTY ◽  
AILEEN A. URQUHART

Dry matter and nitrogen (nitrate and reduced) accumulation and redistribution in four different spring wheat (Triticum aestivum L.) genotypes grown at field density were studied on a plant part and whole plant basis over the growing season for 2 yr. The four cultivars displayed significant differences in plant part and total plant dry matter, harvest index, nitrogen content, nitrogen concentration, nitrogen harvest index and nitrogen translocated values at most sample dates in both years. Grain yield was highly correlated with dry matter accumulation (r = 0.88**), while grain nitrogen content was highly correlated with plant nitrogen content (r = 0.95**). Nitrogen harvest index and plant nitrogen content were correlated at anthesis (r = 0.61**), while, as a consequence of this, the amount of nitrogen translocated was highly correlated with plant nitrogen content at anthesis (r = 0.87**). Nitrogen harvest index and harvest index were highly correlated (r = 0.83**), indicating that they may be related processes. Since plant dry matter and plant nitrogen content were not significantly correlated, it should be possible to select simultaneously for these traits to effect grain yield and grain nitrogen content increases on a per-plant basis. Further research will have to be done to determine how these changes will relate to grain nitrogen concentrations and grain yield per unit area.Key words: Wheat, dry matter, nitrogen, yield, protein, Triticum aestivum L.


2001 ◽  
Vol 41 (4) ◽  
pp. 533 ◽  
Author(s):  
R. G. Flood ◽  
P. J. Martin

Plant nitrogen relationships were studied in 10 wheat cultivars sown at 3 sites (Horsham, Boort and Walpeup) in north-western Victoria by determining the nitrogen concentration and nitrogen content of plant components at anthesis and maturity. While the concentration of nitrogen varied in different plant components, whole plants at anthesis had a nitrogen concentration below the value required for maximum growth. The time to anthesis had an influence only on grain yield and grain nitrogen percentage at Horsham. Total assimilation of nitrogen at both anthesis and maturity was more strongly correlated to plant dry matter than plant nitrogen concentration. There was a significant negative correlation between grain nitrogen percentage and both nitrogen harvest index and harvest index. Grain yield was strongly correlated with total nitrogen accumulated at anthesis and more strongly correlated with total nitrogen accumulated at maturity. Grain yield was significantly correlated with nitrogen harvest index and more strongly correlated with harvest index. Grain yield was negatively correlated with grain nitrogen percentage. The negative association between grain nitrogen percentage and harvest index has important implications for the breeding of wheat with higher grain nitrogen percentage while maintaining or increasing grain yield. The results indicated that none of the measured parameters could be used for indirect selection aimed at improving grain nitrogen percentage.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1108
Author(s):  
Dominika Piaskowska ◽  
Urszula Piechota ◽  
Magdalena Radecka-Janusik ◽  
Paweł Czembor

Septoria tritici blotch (STB) is one of the most devastating foliar diseases of wheat worldwide. Host resistance is the most economical and safest method of controlling the disease, and information on resistance loci is crucial for effective breeding for resistance programs. In this study we used a mapping population consisting of 126 doubled-haploid lines developed from a cross between the resistant cultivar Mandub and the susceptible cultivar Begra. Three monopycnidiospore isolates of Z. tritici with diverse pathogenicity were used to test the mapping population and parents’ STB resistance at the seedling stage (under a controlled environment) and adult plant stage (polytunnel). For both types of environments, the percentage leaf area covered by necrosis (NEC) and pycnidia (PYC) was determined. A linkage map comprising 5899 DArTSNP and silicoDArT markers was used for the quantitative trait loci (QTL) analysis. The analysis showed five resistance loci on chromosomes 1B, 2B and 5B, four of which were derived from cv. Mandub. The location of QTL detected in our study on chromosomes 1B and 5B may suggest a possible identity or close linkage with Stb2/Stb11/StbWW and Stb1 loci, respectively. QStb.ihar-2B.4 and QStb.ihar-2B.5 detected on chromosome 2B do not co-localize with any known Stb genes. QStb.ihar-2B.4 seems to be a new resistance locus with a moderate effect (explaining 29.3% of NEC and 31.4% of PYC), conferring resistance at the seedling stage. The phenotypic variance explained by QTL detected in cv. Mandub ranged from 11.9% to 70.0%, thus proving that it is a good STB resistance source and can potentially be utilized in breeding programs.


1970 ◽  
Vol 48 (12) ◽  
pp. 2213-2217 ◽  
Author(s):  
B. Singh ◽  
D. K. Salunkhe

A solution containing 0.5 p.p.m. of atrazine, simazine, igran, or GS-14254 with 0.2% triton-B 1956 was applied to the foliage of 11-day-old seedlings of bush beans, Phaseolus vulgaris L. cultivar Tender-green, growing on vermiculite in a controlled environment. The activities of nitrate reductase, glutamic-pyruvic transaminase, α-amylase, starch phosphorylase, and adenosine triphosphatase were determined 5,10, and 20 days after treatment. In general, the activity of each of the five enzymes was stimulated by the treatment. The results suggest that protein increase following the application of.s-triazines to bean plants may stem in part from an enhanced rate of amino acid formation resulting from the induced increment in nitrate reductase and transaminase activity. The application of these chemicals also creates a metabolic condition favorable for greater use of carbohydrates needed for nitrate reduction and protein synthesis, and as a source of organic acid synthesis.


Author(s):  
Amrita Kumari ◽  
R. D. Ranjan ◽  
Chandan Roy ◽  
Awadesh Kumar Pal ◽  
S. Kumar

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.


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