Type of Document Master's Thesis Author Riche, Curt Jude Author's Email Address email@example.com URN etd-04132004-154236 Title Identification of Soybean Cultivar's Tolerance to Waterlogging Through Analyses of Leaf Nitrogen Concentration Degree Master of Science (M.S.) Department Agronomy & Environmental Management Advisory Committee
Advisor Name Title James E. Board Committee Chair Jim Wang Committee Member Wayne Hudnall Committee Member Keywords
- available soybean cultivars
- nitrogen fixation
- Glycine max
- cell respiration
Date of Defense 2004-03-26 Availability unrestricted AbstractIrrigation to soybean can cause unintended water to pond on the soil surface for more than a desired amount of time. Most soybean acreage in Louisiana is planted on poorly drained clay soils and waterlogging of soybean can cause substantial yield reductions. Although cultural practices are available for ameliorating the adverse effects of waterlogging, little is known about genotypic tolerance, therefore our objectives were to determine if percent leaf nitrogen concentration could be used as a criterion for screening for cultivar tolerance to waterlogging and to identify waterlogging tolerance among 48 commercially available soybean cultivars.
Forty-eight soybean cultivars were planted in May in 2002 and 2003 in an open- ended outdoor greenhouse at Ben Hur Research Farm near Baton Rouge, Louisiana on a Mhoon clay soil. Flooding treatment commenced the day the plants reached V4 and continued for seven consecutive days. Drained and waterlogged treatments were administered in the two halves of the greenhouse. One site received a 1-week waterlogging stress at the V4 growth stage and the other treatment received normal irrigation as necessary to avoid job stress. Each site was randomized complete block design with four replications and one factor (cultivars). Data obtained from the two year study were percent leaf nitrogen, leaf dry weight, and leaf nitrogen uptake. Analysis of variance was done by the combined analysis method of McIntosh (1983) with treatments and cultivars being fixed factors. Mean separation was accomplished by LSD (P<0.05) using appropriate LSD values to compare specific cultivars between drained and waterlogging treatments or to compare cultivars within or across drained and waterlogged treatments.
Results suggested that percent leaf nitrogen concentration can be an effective parameter for screening for waterlogging tolerance. Both cultivar and drainage significantly (P<0.0001) affected yield without significant interactions with other factors. The low C.V. (7.6%) shown by percent leaf nitrogen also supports its use as a screening criterion. Cultivars showing greatest percent nitrogen were not consistent across treatments. The decline in percent leaf nitrogen between treatments was not consistent. No correlation occurred for cultivar percent leaf nitrogen between treatments.
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