Journal of Environmental Biology

Effect of nitrogen on starch and protein content in grain influence of nitrogen doses on grain starch and protein accumulation in

diversified wheat genotypes

B. Asthir¹*, D. Jain¹, B. Kaur¹ and N.S. Bains²

¹Department of Biochemistry, Punjab Agricultural University, Ludhiana-141 004, India

²Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana-141 004, India

*Corresponding Author E-mail: b.asthir@rediffmail.com  

Key words

Amino acids,

Grain quality parameters,

Nitrogen doses,

Triticum aestivum

Publication Data

Paper received : 19.09.2015

Revised received : 16.04.2016

Re-revised received : 16.07.2016

Accepted : 05.08.2016

Abstract

Aim: Nitrogen is a critical input involved in plant metabolism growth and in different biochemical processes. Nitrogen participates directly in amino acid, protein and other cellular component syntheses, which are required for plant growth and development. Therefore, nitrogen application greatly influences starch and protein composition and, very little information is available on the effect of nitrogen fertilizer on protein sub fractions and starch components with little emphasis on quality characteristics. Therefore, the aim of the study was to evaluate the genotypic variation based on starch and protein accumulation under different doses of nitrogen.

Methodology: The present study was conducted to evaluate the effect of different doses of nitrogen in form of urea on grain quality parameters such as protein sub-fractions, starch sub-components from nine wheat genotypes (PBW 621, PBW 590, PBW 509, BW 9183, BW 8989, PBW 550, GLU 1101, GLU 1356, PH 132 4836) at four levels of nitrogen (N) optimal N dose i.e., recommended dose of N [RDN (120 Kg N ha^-1)], suboptimal N dose [RDN-25% (90 Kg N ha^-1)] and supra-optimal N doses [RDN+25% (150 Kg N ha^-1) and RDN+50% (180 Kg N ha^-1)].

Results: PBW 550, BW 8989 and BW 9183 genotypes had higher sugars content (~20 mg g^-1 d.wt.) and starch (~72.8%), whereas amino acids and protein content were low (~0.65 -100.3 mg g-1 d.wt., respectively). Sugar and starch content were inversely correlated with protein and amino acids indicating a compensatory effect. Higher build-up of grain protein in GLU 1101 (126.3 mg g^-1 DW) and GLU 1356 (141.7 mg g^-1 d.wt.) might be due to higher translocation of N from flag leaf to reproductive structures. Gluten constituted major seed storage proteins as its content was comparatively higher over other proteins in genotypes- PBW 590 and PH-132-4836 (~51.7 mg g^-1 d.wt.) at RDN and RDN-25%. Whereas, amylose content was higher in BW 9183, GLU 1101, BW 8989 genotypes (~23.8 mg g^-1 d.wt.) at RDN-25% while amylopectin content was more in BW 9183 and BW 8989 genotypes (~49.1 mg g^-1 d.wt.) over other genotypes at RDN+25% and RDN+50% .   

Interpretation: Due to consistent performance of GLU 1101, GLU 1356, PBW 590, BW 9183 and PH-132-4836 genotypes at sub-optimal nitrogen dose, these genotypes hold future potential for developing new cultivars with better grain quality parameters. 

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