1. THE SORGHUM PLANT, GROWTH STAGES AND ASSOCITED MANAGEMENT PRACTICESBy
IDK Atokple

2. Trait
Bicolor
Guinea
Caudatum
Kafir
Durra
Panicles
Medium sized open panicles with long, slightly stiff rachis branches
Long, loose, glabrous, and pendulous
Medium to large, oblong, dense to slightly open, hairy with stout peduncle with rigid primary branches
Erect, elongated, mostly semi compact and cylindrical panicles
Stiff, dense, compact, ovate to oblong, covered with dense pubescence; branches short, semi-erect, hairy; rachis elongated or hidden; peduncles often recurved, but occasionally erect
Glumes
Long, clasping, thick and coriaceous with obscure nerves, lower glumes are depressed and hairy
Involute, opening widely, hairy; awns conspicuous
Coriaceous, shorter than the large grain, pubescent
Glossy at maturity, moderately coriaceous, and much shorter than grains
Coriaceous on the lower half and slightly to strongly depressed with a central transverse wrinkle, tends to be lightly pigmented
Spikelets
Pedicellate- persistent
Pedicellate- both persistent and deciduous; Sessile- open when mature, thus exposing the grain
Pedicellate- deciduous; Sessile- ovate to elliptical
Sessile- hairy
Pedicellate- large, persistent; Sessile- Obvovate elliptic or rhomboidal
Grains
Elliptic to subglobose, enclosed by the glumes, persistently attached to the panicle, pigmented
Small to medium, biconvex and nearly ovate, some flattened, slightly pigmented
Flat on one side and round or bulging on the other (turtle backed), chalky white or pigmented
Broadly elliptic, sometimes compressed, flattened or biconvex
Medium sized to large, biconvex with broad tip, wedge-shaped base.

3. Sorghum Plant
Stem
Nodes and internodes
Length – 0.5 to 4.0m
Diameter: 0.5 to 5.0 cm
Leaf
Alternate arrangement in two rows
Sheath+blade/lamina
Width: 1.5 to 13cm
Length: 30 to 135cm
Number: 7 to 30
Panicle
Compound raceme
Width: 2 to 20cm
Length: 4 to 25cm
Central rachis; 1o,2o,3o branches
Peduncle: erect or recurved
Spikelets in pairs – i) sessile & bisexual; ii) pedicillate & male/sterile; Terminal sessile has two pedicillate spikelets

4. Outer glume
Inner glume
Outer lemma
Inner lemma
Outer palea
Inner palea
Lodicules
Anther
Filament
Stigma
Style
Ovary

5. Anthesis Sorghum - often-cross pollinated crop
Flowering pattern: basipetal
Lodicules swell, create pressure on glumes – flower opens
Stigma, anthers emerge simultaneously, varietal differences exist
Flowering starts in 1-4 days of complete panicle exertion
Flowers in a horizontal plane open at the same time.
Flowering is completed in 7 to 8 days – depends on size of panicle, temperature and humidity at flowering, genotype.
Pedicellate spikelets flower 2 to 4 days after the sessile spikelet on the same branches.
The blooming occurs at early in the morning at about midnight 2 am and continues until 8am in south India

6. Pollination Primarily wind pollination
Filaments elongate rapidly, anthers become pendant
Pollen viability – 3 to 6 hours in anther sac, 20 min. after release, depends on weather
Stigmas receptive for a day or two after blooming, but up to a week reported, depends on weather
2000 to 4000 sessile spikelets in a single inflorescence
5000 pollen grains in each anther on an average
Pollen under refrigeration is capable of fertilization for 3 to 4 days

7. Seed Development
After fertilization, ovule develops, changes color - light green, cream-colored; dark green to genotype specific color at maturity
Grain development stages - milky, soft dough, hard dough, physiological maturity, maturity
Physiological maturity – max. dry wt., black layer at the hilar region
Seed moisture level - 10 to 15% at 20 to 25 days after physiological maturity
Seed harvested at any time from physiological maturity to seed dryness; seed with more than 12% moisture to be dried before storage.
Seeds harvested and dried at physiological maturity – good quality

9. Growth stages Stage 0 (Emergence)
Seedlings seen above the soil surface.
Takes about 4 days.
Emergence depends on depth of planting, seed vigor and soil moisture, temperate and physico-chemical characteristics.
Management guide:
Adequate moisture in the top 015 cm soil profile to be maintained.
Use of pre-emergence herbicide, atrazine 1.0 kg ha-1) immediately after planting will prevent weed growth.
In case of crust, light sprinkler irrigation allow rapid emergence.

10. Stage 1 (3-leaf stage) Seedlings have three fully expanded leaves
Occur at 6 days after emergence (DAE)
Seedlings grow to a height of 20 cm.
Management guide:
Weed control is crucial for increasing crop yields.
Seedlings are infested by shoot fly at this stage.

11. Stage 2 (5-leaf stage) Seedlings have five fully expanded leaves
Occur at 16 days after emergence (DAE)
Seedlings grow to a height of 50 cm.
Seedlings enter in to ‘grand period of growth’
Management guide:
Shoot fly, weed competition, nutrient, and water stress reduce the crop stand. Prolonged cold, wet, and cloudy weather causes purple coloring on the leaf sheath and blades, besides iron chlorosis.
Crop should be thinned to one seedling per hill
Soil application of carbofuan 3G (20 kg ha-1) or phorate10G (15 kg ha-1) for shoot fly; and need-based application of carbofuran 3G or phorate 10G inside the plant whorls 8 and 12 kg ha-1) at 30 and 45 DAE protects the plant from stem borer damage.

12. Stage 3 (Panicle initiation stage )
Identified at 32 DAE
Meristem transforms from vegetative (leaf producing) to reproductive phase (panicle producing)
Seedlings grow to a height of 95100 cm, develop 9-10 leaves, depending upon maturity group, and the basal 23 leaves become senescenced
Panicle initiation can be observed
Culm growth increases rapidly following this stage.
Management guide:
Top-dressing of nitrogen fertilizer to hasten the panicle growth
Inter-cultivation and weeding promotes root growth and conserve the soil moisture
Stem borer can be managed with the application of carbofuran granules inside the plant whorls

13. Stage 4 (Flag leaf (final leaf) visible)
Identified at 50 DAE
Appearance of tip of flag leaf in the whorl
Exhibit rapid leaf and culm elongation
Seedlings grow to a height of cm,
All the leaves except the top 34 are expanded, and the basal 35 leaves may be dropped due to senescence
Management guide:
Severe water, nutrient and insect pests damage reduces the potential seed number
Inter-cultivation should be avoided to prevent pruning of expanding root system, loss of soil water, and nutrient uptake.
Continuous stem tunneling by the spotted stem borer may delay the emergence of flag leaf.

14. Stage 5 (Boot stage) Identified at 60 DAE
Swollen flag leaf sheath enclosing the panicle, gives the appearance of boot shape
Maximum leaf area attained and panicle development completed
Seedlings grow to a height of cm
Plant experiences high water demand
Management guide:
Severe drought stress during this stage may shorten the peduncle length and prevent complete exertion of the panicle
Protective irrigation under moisture stress over a period of >10 days help realize maximum yields.
Due to stem tunneling by stem borer, panicle exertion may be either affected or delayed.

15. Stage 6 (50% flowering)
Identified at 6870 DAE when 50% of the plants in the field are in anthesis
Plant grow to a height of 150160 cm.
Flowering typically start 57 days after panicle exertion and progress from the tip to bottom of the panicle.
Flowering duration (from starting to end) usually takes 49 days.
Management guide:
Moisture stress results in poor seed filling.
Midges will get attracted due to flowering panicles, and lay eggs inside the florets resulting in poor/no seed setting.
Head bug is another insect pest that affects grain development.
These pests can be managed by spraying of endosulfan 35EC or carbaryl 50 SP 1 L in 500 Lt water ha-1).

16. Stage 7 (Soft dough stage )
Identified at 80 DAE
Presence of little or no milk when kernel is squeezed between fingers
This stage signals the end of culm elongation, plants grow to about 170 cm tall
About 8 to 10 functional leaves are observed and may vary with the cultivar.
Management guide:
High humid conditions and prolonged rainfall following flowering result in grain mold, and cause loss in grain weight and quality.
Head bug population buildup may increase rapidly, if unchecked, which may result grain shriveling and predispose the seed to grain mold infections.
Spraying malathion 10D 20 kg ha-1 helps manage headbugs.

17. Stage 8 (Hard dough stage )
Identified at 96 DAE
Seed cannot be compressed between fingers
Plants become susceptible to lodging and charcoal rot if the crop suffers from severe moisture stress, severe pest and disease attack, heavy rain or hail driven by wind
Management guide:
Adequate application of farm yard manure helps retain soil moisture for longer period.
Management of stem borer enhance crop yield.
The use of appropriate maturity duration cultivars and those with genetic tolerance to grain mold are best ways to minimize damage due to grain mold.

18. Stage 9 (Physiological maturity stage )
Identified at 106 DAE
Dark spot (black layer) appears at the basal portion of seed
Seed moisture content at this stage varies between 25% and 35% and seeds gain maximum dry weight.
The crop could be harvested at 20% seed moisture content. The seeds but must be dried to 14% moisture content for safe storage.
Management guide:
Crop should be harvested immediately after physiological maturity to avoid the grain mold incidence and crop lodging.
Grain mold incidence to some extent can be controlled by spraying captan (0.3%) plus dithane M-45 (0.3%) thrice at 10 day intervals during grain filling stage.
Harvested grains are predisposed to storage pests when kept for long term storage. The seed may be treated with malathion 10% dust 2 g kg-1 seed to protect from storage pests.

19. How a sorghum plant grow & develop

20. Thank You