Measurement of instantaneous nitrogen use efficiency among pearl millet genotypes

Alagarswamy, G and Gardner, J C and Maranville, J W and Clark, R B (1988) Measurement of instantaneous nitrogen use efficiency among pearl millet genotypes. Crop Science, 28 (4). pp. 681-685. ISSN 0011-183X

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Abstract

Nitrogen is often a limiting factor in pearl millet [Penuisetum glaucum( L.) R. Br.] production. Genotypesa re knownth at differ their responset o N. In this study four pearl millet genotypes,w hich werep reviouslyi dentified as extremesi n N use efficiency (total above ground biomass/unit of N absorbed) in the field, were comparedi n nutrient solution culture for their responset o N supply and the instantaneous measuremenot f photosynthetic N efficiency (~tmol CO2 g-~ N s-a). The latter componenpt ossibly contributes to N use efficiency N-efficient genotypes, ’Souna B’ and 700112, and N-inefficient genotypes, ’BK560a’ nd ’B J104’, were growna t four N levels containing 60, 120, 180, and 240 mg N plant-~. Specific leaf area (cm2 g-a) was calculated from an accompanyingg rowth analysis. Leaf CO2 exchange rate was measured on several leaves as they became fully expanded. Photosynthetic N efficiency was derived using values of leaf N concentration. Nitrogen-efficient genotypes maintained thicker leaves (316.1 vs. 332.5 cm2 g-l) and were generally less responsive in terms of leaf N concentrations and leaf COs exchanger ate (CER)t o the N available in solution as comparetdo the N-inefficient genotypes. Souna B, the most efficient genotype, maintained a stable CER across all N levels. Photosynthetic N efficiency was similar for all genotypese xcept BK560w, hich was ~]0 to 15% less efficient. The small difference in photosynthetic N efficiency among genotypes coupled with relatively high photosynthetic N efficiency values of BJI04 (N-inefficient genotype) suggests that differences in instantaneous measures of N use efficiency occurring during photosynthesios ffer little explanationf or overall differences in N use efficiency among these genotypes in a previous field study. Nitrogen use efficiency was more related to the partitioning of N resources available into additional leaf area

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Uncontrolled Keywords:	Pennisetum glaucum (L.) R. Br., Nitrogen response, Photosynthesis, Leaf nitrogen content, Leaf area.
Subjects:	Mandate crops > Millets
Depositing User:	Mr T L Gautham
Date Deposited:	21 Oct 2011 10:31
Last Modified:	02 Nov 2011 05:55
URI:	http://oar.icrisat.org/id/eprint/3075
Official URL:	http://dx.doi.org/10.2135/cropsci1988.0011183X0028...
Projects:	UNSPECIFIED
Funders:	UNSPECIFIED
Acknowledgement:	UNSPECIFIED
Links:	Author

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