1. MAIZE (Zea mays) PRODUCTION

2. INTRODUCTION Originated in central America (Mexico)
Came to Africa in the 16th century (traders)
In Zimbabwe production started in 1913
Before, staple food were millets and wild fruits
Today the staple food of Zimbabwe, why?

3. USES OF MAIZE 3rd most important cereal after wheat and rice
Human food
Animal feed
Cooking oil, soap margarine, ice cream cones cornflakes, zapnaks etc
Brewing, starch, confectionary industries,
Ethanol production in Brazil (petrol blend)

4. PRODUCTION IN ZIMBABWE
White and yellow maize produced by farmers.
NR11 has used to have the largest hectares under maize, statistics altered by the land reform programme.
Grown in all natural regions 11-V of Zimbabwe
Have different varieties bred to suit all agro-ecological areas of Zimbabwe.

5. MAIZE PRODUCTION TREND
National average yields over years (t/ha)
1913:
1950: : : : : :

6. Reasons for the trend Use of OPVs (Hickory king, Salisbury white)
Improved varieties (SR52) 1st single cross hybrid in the world to sold commercially.
Improved agronomic practices through Research.
Disease and pest control
Use of fertilizers etc

7. MAIZE GROWTH STAGES
Divided in to vegetative, reproductive and maturation stages
Stage 0: From planting until seed is visible above the soils surface (germination -emergency). Takes 6-10 days, temperature depended. Optimum 20-30C. 60%RH.
Stage1: Four leaves completely unfold. Predetermined genetically in varieties.

8. Seed maize before emergency

9. Growth stages cont...
A new leaf unveils every 3 days. Apical bud will be below the soil surface.
Stage 2: eight leaves completely unfolded. LA increases 8-10 times. Expansion phase, lots of water needed. Ear initiation + tillers begin to develop. Apical bud, 5-7cm above soil surface
Stage 3: Twelve leaves completely unfolded. Tassel start developing rapidly Lateral shoot bearing cob (6-8 node)develop rapidly= wk 4.

10. Growth stages cont...
Stage 4: Sixteen leaves completely unfold. Stem lengthen rapidly. TD. Coz of high nutrient demand. Tassel almost fully developed. Silk begin to develop and lengthens from the base of the ear. 4-6wks. High nutrient demand
Stage 5: Silk appear, pollen shading began. All leaves unfolded and tassel visible for 2-3 days. 2nd TD. High nutrient demand.
Stage 6: Green mealie stage, sugars begin to accumulate in the endosperm- the milk stage.

11. Growth stages cont...
Stage 7: Soft dough stage. Sugars converted to starch resulting in starch accumulation in seed
Stage 8: Hard dough stage. Sugars in kernel disappear rapidly. Starch accumulates in the crown of the kernel.
Stage 9: Physiological maturity stage. Beginning of the drying process. Increased water loss from the seed in prep for storage.
Stage 10: biological maturity stage. Seed dries up to 12.5% moisture contend, Takes about 210 days

12. CLIMATIC REQUIREMENTS
Is a warm weather crop.
T min for germination is 10oC (base temp)
T opt 20-30oC. Above 32 pollination is affected, pollen sterilised. Prone to frost.
About 10-16kg of grain is produced for every mm of water used/ha (Water requirements)
Soils with good effective depth, morphological properties, opt moisture regime, balance nutrition. Clay loams soils are best.

13. varieties SR52 R215 SC403 SC513 SC615 SC709 PHB30B50 PHB3253 PHB30G97
PAN53
CG4141
ZM521

14. SELECTION OF MAIZE CULTIVARS
Growing season (late, medium and early maturing varieties and examples) add 3.7 days for every 100m increase in alt.
Consumer prefence (white/ yellow for food/feed)
Yield potential of variety
Pest and diseases resistance
Altitude and air temperature

15. SELECTION OF CULTIVARS CONT..
Hybrid perfomance vs OPVs

16. CULTIVARS SELECTION CONT...
Level of management (Is farmer as well as variety depended)
PLANT POPULATION
Optimum plants/ha most dryland areas
If potential for higher yield exists can increase upto plnts/ha. (dryland/ irrigated)
To increase population var shld resist lodging, short(growth regulators shorten internodes), have erectrophile leaves

17. Plant population/ Tillage
Aim at plnts/ha if target yield is >10t/ha
Under marginal conditions decrease population to even plnts/ha (Lowveld)
TILLAGE
Types: (primary and secondary)
Practices: (conventional, conservation, reduced/minimum, zero ?
Conventional,reduced,conservation
Crop rotations (soyabeans, groundnuts, field beans, cotton