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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #298986
Title: Response of four cotton genotypes to N fertilization for root hydraulic conductance and lint yield

Author
item Bauer, Philip
item Pettigrew, William
item Campbell, Benjamin - Todd

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2014
Publication Date: 1/13/2015
Citation: Bauer, P.J., Pettigrew, W.T., Campbell, B.T. 2014. Response of four cotton genotypes to N fertilization for root hydraulic conductance and lint yield. Journal of Cotton Science. 18:362-366. Available: http://journal.cotton.org.

Interpretive Summary: Nitrate concentration in the rooting medium affects the conductivity of water in plant roots in greenhouse and laboratory studies. We tested this under field conditions. We also evaluated whether cotton genotypes that were developed under a range of environments differ for root hydraulic conductance. In the experiment, plants that received no nitrogen fertilizer had the same root hydraulic conductance as plants that received 112 kilograms of nitrogen per hectare. Also, we found all four genotypes had similar root hydraulic conductance. Although root hydraulic conductance was not influenced by the treatments in our study, both fertilizer nitrogen rate and genotype had a significant influence on cotton lint yield and yield components. These results will be used by cotton researchers developing new cotton production methods to improve nitrogen and water use efficiency.

Technical Abstract: In controlled environments, hydraulic conductance of cotton (Gossypium hirsutum L.) roots is affected by nitrate supply. Limited information is available on the influence of N on cotton root hydraulic conductance under field conditions. The objective of this study was to determine the effect of N fertilization and genotype on cotton root hydraulic conductance and lint yield under field conditions. The experiments in this study were conducted in 2009 and 2010 at Florence, SC and Stoneville MS. Treatments were two N rates (0 and 112 kg N ha-1) and four genotypes (AGC 85, PD 2, Siokra L23, and Tamcot 22). Root hydraulic conductance was measured twice each year at Florence and once each year at Stoneville. Nitrate-N was determined in stems of plants selected for root hydraulic conductance measurements. Cotton yield was measured at the end of the season. Stem NO3-N concentration was higher in the N-fertilized cotton plant stems than in the stems of the unfertilized plants at all measurement times. No differences occurred among N rates or genotypes for root hydraulic conductance. Nitrogen fertilizer increase yield by 47% at Florence and by 23% at Stoneville. An N rate X genotype interaction occurred for lint yield at Stoneville. Nitrogen fertilization significantly increased lint yield for ‘AGC 85, ‘Siokra L23’, and ‘Tamcot 22’ but not for ‘PD 2’. No significant interaction between N rates and genotypes occurred at Florence, but the genotype response to N rate there was similar to the yield response in Stoneville. All four genotypes had similar increases in boll weight and decreases in lint percent with N fertilization, suggesting that the differential yield increase among genotypes with N was due to boll number and not yield components.