Crop Structure and Development

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Crop Structure and Development

• Montana Small Grain Guide

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Crop Structure

• Roots anchor plant, absorb water nutrients
• Seminal Roots first to emerge from embryo,
  function throughout plant life
• can have 3 to 6 seminal roots
• Crown roots originate from lower node of the
  main stem and tillers
• each tiller has crown roots

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Crop Structure

• Culms (stems) support for leaves and heads
• one culm, plus additional tillers
• divided into nodes and internodes
• Leaves photosynthesis
• each node produces one leaf
• Sheath part of leaf wrapped around the stem
• Blade visible part of leaf

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Crop Structure

• Collar thickened part where blade joins collar
• Ligule protective tissue within sheath at the
  collar area
• Auricles appendages at the base of the leaf
  blade
• Presence, size and shape of Ligules and Auricles
  used in plant identification

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Crop Structure

• Flag Leaf top leaf, stays green longest, may
  account for 80 of the filling of the grain
• Heads where seed is produced
• Wheat Head has several spikelets that
  contain 2-6 florets (usually only 2-3 produce
  seed)
• Barley Head has 3 spikelets
• 6-row barley each spikelet has one fertile
  floret
• 2-row barley only center spikelet has a fertile
  floret

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Crop Development

• Growing Degree Days average of minimum and
  maximum daily temps. Minus base temp (37 deg. F)
• ex temps 40 and 58
• avg. 98 / 2 49
• 49 - 37 12 GDD
• Emergence usually 50 complete at 85-100 GDD

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Crop Development

• Tillering begins at the 3 leaf stage
• Ideal conditions, new tillers formed at the
  formation of each new leaf after 3 leaf stage
• Stress will cause plant to skip some tillers
• Germination 35 - 40 soil moisture
• min temp 34-36 degrees
• optimum temp 59-65 degrees
• max temp 95-104 degrees

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Tillering

• May start 7 days after emergence
• Factors affecting tillering large seed size,
  high soil fertility, physical condition of soil,
  optimum soil temp, optimum water content,
  relatively low density of plants
• 2-6 tillers per plant common
• Tillering stage lasts about 4 weeks

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Jointing Stage

• Follows tillering, rapid growth period (boot
  stage, shooting)
• stems and leaf sheaths elongate rapidly
• Lowest internode lengthens first followed by next
  highest etc.

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Heading

• Boot as the head grows, it enlarges the sheath
  of the flag leaf
• Main stem develops first, followed by tillers in
  order of origin
• Uppermost stem continues to lengthen until head
  is above flag leaf
• Flowering begins a few days after head emerges
• Ripening 25-40 days

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