CROP IDEOTYPE CONCEPT- WHEAT, BARLEY, MAIZE AND COTTON

1. CROP IDEOTYPE CONCEPT AND ITS
APPLICATIONS IN PLANT BREEDING
Varsha p vengilat
2017600823

2. • Alternative breeding strategy.
• Concept by Donald in 1968.
• Literal meaning: ‘A form denoting an idea’
• Definition: A crop ideotype is a plant model,
which is expected to yield a greater quantity or
quality of grain, oil or other useful product
when developed as a cultivar.
• Synonyms: model plant type, ideal model plant
type and ideal plant type.

3. Types of ideotype
• Isolation Ideotype- performs best when space planted.
- lax, free tillering, leafy spreading
plant in case of cereals.
• Competition Ideotype- in gentically heterogenous
populations.
-tall, leafy, free tillering plant
(cereals)
• Crop Ideotype- Best at commercial crop densities; a
poor competitor.

4. Development of ideotypes
Following knowledge while developing ideotype:
• Target area and target environment
• Quality considerations
• Current agronomic practices
• Adequate information
• Simulation models can be used as aids

5. Characteristics of a crop ideotype
• A weak competitor
• Efficient in utilizing environmental resources
• Sensitive to cultural practices
• Include morphological and physiological
characteristics that result in high harvest index
• Should be grown in a weed free envt
• Planned selection done for features of crop ideotype

6. Ideotypes of selected crops
RICE
First introduced by Matsushima in 1957, later by Jennings.
Ideotype for dwarf rice(By Chandler):
 Shorter culm length.
 Greater culm diameter
 Lower relative internode elongation under
 heavy nitrogen application
 Short erect leaves,medium length
 High tillering capacity
 More panicles/m2

7. WHEAT
Proposed by Donald(1968)
Short strong stem
Erect leaves
Few small leaves
Large, erect ear
Presence of awns
Single culm
Reduced height
Photoperiod insensitivity
Rust resistance etc.

8. MAIZE
By Mock and Peacre(1975)
 Stiff vertically oriented leaves
above,
and horizontal leaves below
 Max. photosynthetic efficiency
 Efficient translocation
of photosynthates
 Short interval between pollen
shed and silk emergence
 High prolificacy
 Grain filling period should be as
long as possible
 Cold tolerance

9. COTTON

11. PULSES
Determinate plant type
Erect and upright plant
Early vigour, early flowering and synchronous
maturity
Pod bearing from well above the soil surface
More pods/plant & no. of seeds/pod
Hgh Harvest Index
Yield stability

12. STEPS IN IDEOTYPE BREEDING
• Development of conceptual Model
• Selection o base model
• Incorporation of desirable traits
• Selection of Ideal Plant type

13. MERITS
• Effective method of enhancing yield. It exploits both morphological and
physiological variation.
• Provides solution to several problems at a time like disease, insect and
lodging resistance, maturity duration, yield and quality .
• Genes for specific traits can be introgressed from unimproved to
improved gene pool to develop desirable variability for the trait.
• Efficient method of developing cultivars for specific or environment.
• An effective method of breaking yield barriers through the use of
genetically controlled physiological variation for various characters
contributing towards higher yield.

14. LIMITATIONS OF IDEOTYPE BREEDING
• Incorporation of several desirable morphological and
physiological and disease resistance traits from different
sources into a single genotype is a difficult task.
• A slow method of cultivar development
• Changes with change in knowledge, new requirements,
national policy, etc.