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TEMPERATURE AND NITROGEN INFLUENCE ON GROWTH, NITROGEN EFFICIENCY, DRY MATTER AND NITROGEN PARTITIONING OF PEARL MILLET (PENNISETUM AMERICANUM (L.) LEEKE) HYBRIDS
Abstract
Pearl millet is grown under variable soil nitrogen (N) fertility conditions and in areas of temperature extremes. Studies were conducted to determine the influence of N, temperature and plant genotype on dry matter (DM) production, N efficiency and partitioning of N into shoot N fractions. Six hybrids (three females x two males) were grown hydroponically in greenhouses and growth chambers under two N levels (40 or 200 mg N plant('-1)) and four daytime temperatures (growth chambers at 20/20, 25/20, 30/20, and 35/20 C day/night). ('15)N enriched nitrogen was used to observe the incorporation of N into shoot N fractions. Shoot N was fractionated into nonsoluble N (structural proteins and nucleic acids), soluble protein, and soluble nonprotein N (free amino acids and ammonium). In the greenhouse study, hybrids differed for fresh weight, shoot, root and total DM, N efficiency, DM and N partitioning. Hybrids correlated with their female parent for root and total DM, shoot/root ratios for DM and N, and total root N. Plant growth, DM production, N and DM partitioning, and shoot N fractions were influenced by temperature, N level and genotype. Plants developed faster at 30 and 35 C, but total DM was greatest at 25 C. Plants partitioned more N and DM to the shoots under high N and 30 and 35 C. The N concentration and percent of total shoot N in each fraction was influenced by temperature and N level. Hybrids with the highest DM and N use efficiency values had the lowest N concentration and percent total shoot N in the soluble nonprotein fraction. In the labeled N experiment, plants grown at 20 C had a slower uptake and incorporation rate of N into nonsoluble and soluble protein N than plants at all other temperatures. Levels of nonsoluble and soluble nonprotein N increased greatly by 2 days after addition of labeled N while soluble protein showed little increase until 4 days.
Subject Area
Agronomy
Recommended Citation
BLEWETT, THOMAS CRAIG, "TEMPERATURE AND NITROGEN INFLUENCE ON GROWTH, NITROGEN EFFICIENCY, DRY MATTER AND NITROGEN PARTITIONING OF PEARL MILLET (PENNISETUM AMERICANUM (L.) LEEKE) HYBRIDS" (1986). ETD collection for University of Nebraska-Lincoln. AAI8620802.
https://digitalcommons.unl.edu/dissertations/AAI8620802