Investigating Hybrid Interactions with Nitrogen and Foliar Fungicides

Research Questions:

1. Does the response to N depend on plant population and hybrid (or phenotypic traits)?
2. Does the response to nitrogen depend on whether a foliar fungicide was applied at tasseling, and does this response depend on the hybrid (or phenotypic traits)?
3. Does the response to nitrogen depend on whether Acapela was applied in a high population?
4. When yields were affected by nitrogen, plant population, and foliar fungicides what were the main physiological and yield components affected?

Objectives

To characterize the response of corn hybrids with different genetic backgrounds to N for possible interactions across plant populations and the foliar fungicide Acapela.


Methodology

Experimental Protocol:

• A field study proposed between London and Ridgetown, Ontario, Canada (105‐108 CRM)
• Previous crop = wheat (not underseeded to a legume) or soybean
• Experimental design = Split‐split‐split plot with 4‐6 reps (pending resources). See Figure 1.

Main Plot Plant Population (final stand):

1. 32,000
2. 44,000

Split‐plot Foliar Fungicide (applied at VT‐R1) applied with JD 4760 sprayer modified for research

1. Untreated
2. Acapela

Split‐split Nitrogen Rate (lbs N/acre) injected between crop rows with variable rate applicator

1. 0
2. 120
3. 180
4. 240

Split‐split‐split Hybrid (hybrids TBD):

1. PO216AM‐R
2. PO474HR ?
3. PO621R ?
4. 35F50AM‐R ?

Proposed List of Measurements:

• N levels at planting
• Final plant populations in all plots
• SPAD of ear leaf at R2 and R4 stage of development
• Incidence and severity of leaf disease by disease at VT and R4
• Plant harvest at silking and maturity for biomass and HI calculations, and nitrogen harvest index calculations (pending level of funding)
• Carbon Exchange Rate (CER) (Li‐Cor 6400) measured 3 times during grain‐fill, pending funding
• Yield data (grain yield, MC, test weight, thousand kernel weight)
• % barren plants
• Lodging
• Basal stalk diameter at maturity in all plots
• Anthesis‐silking interval