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