Response of Different Physiochemical Parameters of Wheat Genotypes (Triticum aestivum L. & Triticum durum L.) in Nutrient Stress Condition
Authors: Sharma Pramod Kumar , Gurjar Rekha , Saini Ravindar , Meena Dilkhush , Meena Siyaram , Sabal Shashikant Kumar 
Published: February 2023

Nitrogen management strategies during plant growth period are based on chlorophyll content of plant photosynthesis efficiency. This study is aimed to determine the impact of different nitrogen and phosphorus fertilizer rates on the dynamics of chlorophyll content in winter wheat varieties during vegetative and flowering stage to determine the relationship between nitrogen and phosphorus on chlorophyll content in different winter wheat varieties. Field trial involving nine winter wheat (TriticumaestivumL.) varieties. The treatments were T1=Control, T2=100% (N+P+K) T3= 50% N+ 100% (P+K), T4 =50%P+100%N+K.The results of the trial shown that the maximum chlorophyll content in different wheat varieties was observed at the end of flowering stage. The chlorophyll content depended on the level of mineral fertilization. The highest chlorophyll content in leaves, stem and ears was obtained by using normal recommended doses. By using chlorophyll meter Yara N-tester recorded the highest chlorophyll content in all analyzed plant parts in one year trial. Nitrogen and phosphorus fertilization significantly affected chlorophyll content, SPAD value and photosynthesis rates in leaves. Nitrogen and phosphorus fertilization had an important effect on chlorophyll content, SPAD and leaf photosynthesis rates.

Aims: The genotypes with high photosynthetic rate and chlorophyll content characteristics identified in this study could be applied to conventional breeding efforts to more effectively exploit the constrained ecosystem whichminimize environmental impacts.

Place and Duration of Study: This experiment was carried out during 2019-20 at subtropical region of India.

Methodology: In this experimentPhotosynthetic rate was measured by Photosynthesis system (LICOR 6400) at 55 and 85 DAS. The measurement was taken in the morning hours (8 to 11 AM) in the leaf of wheat crop. The results were expressed inμmol m−2 s−1.SPAD meter reading was measured at 90 DAS. SPAD reading was taken in the morning and evening hours on the leaf of wheat varieties in each plot.A method described by Richardson et al. [1] was used for measuring leaf chlorophyll content at 65 and 85 DAS. Leaf samples were collected and washed with distilled water to eliminate dust. The leaf samples (0.25 g) were pulverised and centrifuged with 3 ML of DMSO. The absorbance of the supernatant was measured at 645 and 663 nm by the help of spectrophotometer to compute the total chlorophyll content.

Results: Among the nine wheat varietiesAt 55 DAS, G 366 had highest photosynthetic rate (33.50μmol m−2 s−1) followed by NARMADA14 (33.45 μmol m−2 s−1) and at 85 DAS, HI1531had highest Ps rate (32.60 μmol m−2 s−1). Under normal dose of N, SPAD readings were higher in variety NARMADA14 (48.40), followed by HI8713 (47.70).

Conclusion: Among all the wheat varieties tested, the variety HI 8713 had considerably higher dry weight, leaf area, biomass, grain yield, chlorophyll content, SPAD value and the maximum chlorophyll content was found in optimum dose on N and P plot.HI8737 shows optimum chlorophyll content in nutrient deficient condition.