SELECTION CRITERIA FOR COMBINING HIGH GRAIN YIELD AND PROTEIN CONTENT BASED ON NITROGEN PARTITIONING EFFICIENCY IN WHEAT (Triticum aestivum L.)
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Date
2010
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Punjab Agricultural University, Ludhiana
Abstract
This study was designed to identify selection criteria for the simultaneous improvement of grain yield and grain protein concentration in wheat (Triticum aestivum L.). Three wheat cultivars namely PBW-550, PBW-502 and PBW-343 were sown on 2nd week of November under two nitrogen levels (120 and 180 kg ha-1). Results showed that Cv.PBW-550 found to have maximum remobilization efficiency (78.98%), grain protein yield (90.33 g m-2) and nitrogen harvest index (0.602). This cultivar had higher grain yield (57.34 q ha-1) averaged over both nitrogen level due to maximum number of spikes per plant (7.5), number of kernels per spike (65.67) and 1000- kernel weight (44.43 g) as compared to Cv.PBW-502 and PBW-343.This indicate that Cv. PBW-550 expressed high levels of both traits concurrently. Pearson correlation analysis showed significant positive correlation with grain yield and vegetative nitrogen at anthesis + 12 days (r = 0.9693**), vegetative nitrogen at anthesis + 4 days (r = 0.8527**), accumulated nitrogen (r = 0.8596**), accumulated dry matter (r = 0.7313**) at post anthesis stage. Correlation analysis also indicate significant positive correlation between grain protein concentration (r = 0.8236**), harvest index (r = 0.9833**), total plant nitrogen (r = 0.9710**) and grain protein yield (r = 0.9067**) at physiological maturity. Regression line between grain yield and grain protein concentration showed significant positive relationship (R2 = 0.6948).The correlation and path analysis revealed that the direct effect of vegetative nitrogen at maturity was more (P9 11= 0.5329) followed by remobilization efficiency (P10 11=0.2072) on grain yield. The regression model showed significant positive correlation between grain yield and growing degree days accumulated during booting stage (R2= 0.4709).These results indicated that Cv.PBW-550 showed 12.96% increase in grain yield and 19.62% increase in grain protein concentration due to its high nitrogen remobilization and partitioning efficiency. Nitrogen uptake and nitrogen partitioning function as separate and independent physiological systems in wheat plants. Therefore, improvement in both grain protein percentage and grain yield realized by manipulating nitrogen uptake and its partitioning separately.
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