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Crop Structure and Development. Montana Small Grain Guide. 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
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Crop Structure and Development Montana Small Grain Guide
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
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
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
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
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
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
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
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.
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