1. Crop Structure and Development
Montana Small Grain Guide

2. 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

3. 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

4. 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

5. 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

6. 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
= 12 GDD
Emergence usually 50% complete at GDD

7. 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: % soil moisture
min temp degrees
optimum temp degrees
max temp degrees

8. 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

9. 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.

10. 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 days