Effect of differential nitrogen fertilization and nano zinc seed priming on yield and seed protein quality in finger millet genotypes
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Date
2020-02
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The “green revolution” based modern agriculture helped in increasing crop production and averting the hunger with the use of Nitrogenous fertilizers mainly. However, excessive use of fertilizers has threatened agriculture and sustainability of environment; and reduced the diversity of food, which is a major cause of malnutrition. Agronomic biofortification through direct application of fertilizer is an effective method to overcome the problem of malnutrition; however, fertilizers should be used with caution for both commercial and environmental reasons. Therefore there is need to optimize the dose of fertilizer and to use naotechnological interventions so as to produce nutritionaly rich food without compromising yield and damaging the environment. Such approaches will not only biofortify the crops but also ensure environment-friendly agriculture by promoting low-input sustainable crop cultivation. Finger millet (Eleusine coracana), holds immense agricultural and economic importance due to its high nitrogen use efficiency and richness in proteins being good source of essential amino acids and minerals. Two genotypes of finger millet viz. GE-1437 and GE-3885 were taken for the study to observe the effect of differential nitrogen fertilization without and with nano zinc seed priming (5ppm) on agro-morphological parameters, seed protein content, seed zinc content, expression analysis of seed storage proteins, regulatory genes of essential amino acid metabolism and accumulation of seed storage proteins. Results of agro-morphological data analysis showed the maximum biomass, grain yield and zinc content was obtained at 60kg/h urea without nano zinc seed priming; and 40kg/h urea with nano zinc seed priming. Nine regulatory genes involved in metabolism of essential amino acids have been identified from the transcriptome of finger millet spike. Promoter analysis revealed the presence of various cis-regulatory elements in the regulatory genes i.e. GCN4 motif, O2-site, G-box and GATA-motif, P-box etc. which are found to play an
important role in N metabolism, SSP synthesis, light response, hormone response or stress response and directly or indirectly may regulate the biosynthesis of essential amino acids. Among the treatments without nano zinc seed priming the maximum expression of all the seed storage proteins was obtained with 40kg/h urea at later stages of spike development. On the other hand, for the treatments with nano zinc seed priming, the maximum expression of all the SSPs was obtained with control and 80kg/h urea at later stages of spike development. Both the genotypes showed higher expression of most of the regulatory genes with farm yard manure without and with nano zinc seed priming. The comparative analysis showed the higher expression of globulin and prolamin with the treatments without nano zinc seed priming and albumin with the treatments with nano zinc seed priming at later stages of spike development. SDS-PAGE further confirmed the increase in globulin and prolamin with the treatments without nano zinc seed priming and albumin with the treatments with nano zinc seed priming in mature seeds. Results of present investigation have suggested that high productivity/yield along with high Zn content of Finger millet can be obtained upon application of 40kg/h urea with nano zinc seed priming. Though this treatment can be used to solve Zn malnutrition problem among the masses yet it compromises with quality of protein and protein content in grains. In order to solve protein malnutrition problem, however, one can apply 40kg/h urea without nano zinc seed priming to enhance the seed protein content and quality in terms of essential amino acids.