Presentation on theme: "THE SORGHUM PLANT, GROWTH STAGES AND ASSOCITED MANAGEMENT PRACTICES"— Presentation transcript:
1 THE SORGHUM PLANT, GROWTH STAGES AND ASSOCITED MANAGEMENT PRACTICES ByIDK Atokple
2 TraitBicolorGuineaCaudatumKafirDurraPaniclesMedium sized open panicles with long, slightly stiff rachis branchesLong, loose, glabrous, and pendulousMedium to large, oblong, dense to slightly open, hairy with stout peduncle with rigid primary branchesErect, elongated, mostly semi compact and cylindrical paniclesStiff, dense, compact, ovate to oblong, covered with dense pubescence; branches short, semi-erect, hairy; rachis elongated or hidden; peduncles often recurved, but occasionally erectGlumesLong, clasping, thick and coriaceous with obscure nerves, lower glumes are depressed and hairyInvolute, opening widely, hairy; awns conspicuousCoriaceous, shorter than the large grain, pubescentGlossy at maturity, moderately coriaceous, and much shorter than grainsCoriaceous on the lower half and slightly to strongly depressed with a central transverse wrinkle, tends to be lightly pigmentedSpikeletsPedicellate- persistentPedicellate- both persistent and deciduous; Sessile- open when mature, thus exposing the grainPedicellate- deciduous; Sessile- ovate to ellipticalSessile- hairyPedicellate- large, persistent; Sessile- Obvovate elliptic or rhomboidalGrainsElliptic to subglobose, enclosed by the glumes, persistently attached to the panicle, pigmentedSmall to medium, biconvex and nearly ovate, some flattened, slightly pigmentedFlat on one side and round or bulging on the other (turtle backed), chalky white or pigmentedBroadly elliptic, sometimes compressed, flattened or biconvexMedium sized to large, biconvex with broad tip, wedge-shaped base.
3 Sorghum PlantStemNodes and internodesLength – 0.5 to 4.0mDiameter: 0.5 to 5.0 cmLeafAlternate arrangement in two rowsSheath+blade/laminaWidth: 1.5 to 13cmLength: 30 to 135cmNumber: 7 to 30PanicleCompound racemeWidth: 2 to 20cmLength: 4 to 25cmCentral rachis; 1o,2o,3o branchesPeduncle: erect or recurvedSpikelets in pairs – i) sessile & bisexual; ii) pedicillate & male/sterile; Terminal sessile has two pedicillate spikelets
5 Anthesis Sorghum - often-cross pollinated crop Flowering pattern: basipetalLodicules swell, create pressure on glumes – flower opensStigma, anthers emerge simultaneously, varietal differences existFlowering starts in 1-4 days of complete panicle exertionFlowers 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 pendantPollen viability – 3 to 6 hours in anther sac, 20 min. after release, depends on weatherStigmas receptive for a day or two after blooming, but up to a week reported, depends on weather2000 to 4000 sessile spikelets in a single inflorescence5000 pollen grains in each anther on an averagePollen under refrigeration is capable of fertilization for 3 to 4 days
7 Seed DevelopmentAfter fertilization, ovule develops, changes color - light green, cream-colored; dark green to genotype specific color at maturityGrain development stages - milky, soft dough, hard dough, physiological maturity, maturityPhysiological maturity – max. dry wt., black layer at the hilar regionSeed moisture level - 10 to 15% at 20 to 25 days after physiological maturitySeed 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 015 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 hillSoil 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 DAEMeristem transforms from vegetative (leaf producing) to reproductive phase (panicle producing)Seedlings grow to a height of 95100 cm, develop 9-10 leaves, depending upon maturity group, and the basal 23 leaves become senescencedPanicle initiation can be observedCulm growth increases rapidly following this stage.Management guide:Top-dressing of nitrogen fertilizer to hasten the panicle growthInter-cultivation and weeding promotes root growth and conserve the soil moistureStem 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 DAEAppearance of tip of flag leaf in the whorlExhibit rapid leaf and culm elongationSeedlings grow to a height of cm,All the leaves except the top 34 are expanded, and the basal 35 leaves may be dropped due to senescenceManagement guide:Severe water, nutrient and insect pests damage reduces the potential seed numberInter-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 shapeMaximum leaf area attained and panicle development completedSeedlings grow to a height of cmPlant experiences high water demandManagement guide:Severe drought stress during this stage may shorten the peduncle length and prevent complete exertion of the panicleProtective 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 6870 DAE when 50% of the plants in the field are in anthesisPlant grow to a height of 150160 cm.Flowering typically start 57 days after panicle exertion and progress from the tip to bottom of the panicle.Flowering duration (from starting to end) usually takes 49 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 DAEPresence of little or no milk when kernel is squeezed between fingersThis stage signals the end of culm elongation, plants grow to about 170 cm tallAbout 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 DAESeed cannot be compressed between fingersPlants 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 windManagement 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 DAEDark spot (black layer) appears at the basal portion of seedSeed 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.