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Corn Production Guide (R Stages (R1 (-This is the silking stage.
-This…
Corn Production Guide
R Stages
R1
-This is the silking stage.
-This stage begins when silk is visible outside the husks.
-The number of ovules fertilized is determined now.
-At this point, potassium uptake is about complete.
-Nitrogen and phosphorus uptake is rapid.
-Nutrient content of the leaf correlates highly with final yield.
-It takes 1400 MGDD to get to R1, and 75 days after planted.
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R2
--This stage is called blister.
-- It begins 10-14 days after R1.R2 kernels are white on the outside and resemble a blister.
--Kernels are beginning to accumulate dry matter.
-- Seed-fill is beginning.It takes 1600 MGDD to get to this stage, and 86 days after planting
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R3
--This stage is called milk.
--The R3 kernel is yellow outside
--The inner fluid is now milky white due to accumulating starch.
--Silks are brown and dry, or becoming dry.
--It takes 1925 MGDD to get to this stage
--96 days after planting.
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R4
-R4 is the dough stage of corn
-Dough stage takes place at around 2,190 heat units at around 108 days.
-This is when the inside of the kernel turns from a milky consistency to a doughy consistency.
-It is very similar to play dough.
-Starch accumulation continues into the endosperm.
-The shelled cob is a light red or pink.
-Kernel moisture is around 80% :
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R5
-R5 is the Dent stage of corn
-Dent stage takes place at around 2,450 heat units or around 119 days.
-At the start of Dent the kernels begin to lose moisture.
-The milk line begins at this stage.
-It marks the boundary between the milky and stretchy areas of the kernel.
-The milk line slowly disappears from R5 to R6 stage until it is gone shortly after maturity
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R6
-R6 is the final stage of corn.
-This is when corn has reached physiological maturity.
-This takes place at around 2,000 heat units or 132 days.
-Kernel dry weight reaches its maximum.
-Maturity begins shortly after the kernel milk lines disappear and just before the black layer forms at the kernel tip.
-The black layer eliminates any more moisture from entering the kernel.
-Kernel moisture at maturity can vary from 40-25% moisture.
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V Stages
V1
-when you can see the collar on the first leaf -first leaf is more rounded at the tip -other leaves start growing below surface -typically 3-4 days after emergence
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Variable
-Variable can be anything from V1 to V25
-Helps know when to spray some chemicals -V2 is typically around 200 GDU, V6-475, V8-610
Vegetative Emergence
-occurs when the coleoptile pushes through surface -can take5 days-3 weeks
-helps farmers have a field plan -Typically requires 100-120 GDU ![uploaded image]
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Vegetative Tassel
-as soon as the tassel emerges from the leaf wraps -This is when the plant reaches its maximum height
-tassel typically emerges a couple days before the silk emerges -helps the farmer keep track of the pollination in the field.
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