Commercial-Cassava-Production-Technical_Bulletin-Final

Recommendations

Info

Commercial Cassava Production Technical BulletinTissue Cultured Planting MaterialRECOMMENDED VARIETIESCaribbean producers recognise two types of cassava: bitter andsweet. Both contain cyanide but the content is higher in the bittertype. The sweet cassava only requires cooking in order to reducethe cyanide content to non-toxic levels. However, the bitter cassavarequires more thorough preparation before consumption.There are many local varieties and growers in each country inthe Region have their particular preferences. Some of these are:Sugarloaf, Butterstick, Puntstick, Red Stick, Blue Stick, MaracasBlack Stick, Green stem, Pickne Moma and Guyana Sweet.Tissue cultured cassava planting material at the in vitro multiplication stageTubers of a local varietyTissue culture cassava plantlets hardened and ready for plantingPlantlets generated by the tissue culture method will provide alarge quantity of clean (i.e. free of insects, mites and pathogens)planting material of consistent quality. Tissue culture refers to theproduction of cassava plantlets resulting from the growth of cellsfrom the apical meristem or shoot tip of the cassava plant. Thisis done under controlled and hygienic conditions in test tubes(in vitro) in a laboratory. Eventually, the plantlets are weanedand hardened under a Saran netting shed to ensure that theyare properly rooted, vigorous and properly acclimatized beforedistribution to the farmer for planting in the field. The tissue culturefacilities at Orange Hill Station in Saint Vincent and the Grenadinesstores a selected germplasm collection in vitro and accepts ordersfor young plants.There are also improved varieties from CIAT, which are generallyhigher yielding and have been bred for tolerance to particularpests such as bacterial blight, super-elongation and thrips.The CARDI Unit in St Vincent and the Grenadines evaluatedseveral varieties obtained from CIAT. The Institute subsequentlyconducted evaluations of selected varieties in Montserrat andSt. Kitts and Nevis.Tubers of an improved variety6
Commercial Cassava Production Technical BulletinTable 1: Characteristics of cassava CIAT varieties evaluated by CARDI in St. Vincent and the GrenadinesClonePLANTINGBitter/SweetTime toharvest(mths)FleshcolourDry matteryield(t/ha)Cassava stakes can be planted slanted, vertically or horizontally.For wet areas, it is better to plant vertically or slanted, as horizontalplanting may cause the stakes to rot. In dry areas, place the stakeshorizontally. Stakes should be planted 5–10 cm [2–4 in] deep. Forstakes that are planted slanted or vertically, only one node shouldbe visible above ground.Dry mattercontent (%)HCN(ppm)CassavaBacterialBlight*SuperelongationDisease*CM 3306-4 Sweet 9-11 White 9-12 38 51 I I RCM 6740-7 Sweet 11-12 White 9-14 37 92 R I RCM 4919-1 Bitter 9-11 Yellow 9-15 38 593 R S RCM 4843-1 Bitter 8-11 White 9-12 35 331 R R IM Bra 383 Sweet 10-12 White 9-11 34 95 I S RCM 7514-8 Bitter 10-11 White 9-15 40 156 R I R*R: resistant, S: Susceptible, I: Intermediate, ppm: parts per million, mths: months, t/ha: tons (1000kgs) per hectare, HCN: Hydrogen Cyanide.The CIAT varieties evaluated are available from the Orange Hill Tissue Culture Laboratory.Thrips*Establish single rows on each prepared bed. Space plants 50 cm[20 in] between each other for those varieties with a compact habitand 75 cm [30 in) for those plants with a spreading habit.Where the terrain allows, use mechanical planters to ensuremore uniform spacing and depth of planting. Mechanized plantingburies the stake horizontally from 5 to 20 cm [2 to 8in] deep. Tworows can be planted at the same time and some planters alsodeliver chemical fertilizers during planting.Cassava PlanterCassava stake placed horizontally by the mechanical planter (circled)APPLYING FERTILIZERSCassava plants have a long growth period, requiring adequateamounts of the major nutrients—nitrogen, phosphorus, potassiumand magnesium—as well as other nutrients particularly, boron,manganese, zinc and calcium at specific times in the life cycle ofthe crop. Remember that the cassava plant grows best at a pH of5.5 to 6.5 because it is at this pH that nutrients become availablefor plant growth.Fertilizer use is closely associated with the growth phases ofcassava. Fertilization is critical during the first phase at 6-8 weeksafter planting. This is when the thin and thick roots are being rapidlyproduced and can absorb the nutrients from the soil. Fertilizationis also important during the second phase, at 16 weeks afterplanting, when the tubers begin to bulk up and there is a highdemand for sucrose, which is stored in the tubers. Potassium isthe most important fertilizer to apply at this time because its helpsin mobilizing the sucrose produced in the leaves and translocatingit to the tubers where it is converted to starch.7
Page 2 and 3: ContentsPREFACE 3INTRODUCTION 3THE
Page 4 and 5: Commercial Cassava Production Techn
Page 16: Commercial Cassava Production Techn

Commercial-Cassava-Production-Technical_Bulletin-Final

Create successful ePaper yourself

Delete template?

Save as template?