2. Ideotype term was given by C.M. Donald (1968)
Ideotype: “A biological model, which is expected to perform or behave in a
predictable manner within a defined environment.”
According to Donald: A crop ideotype is a plant model which is expected to yield
greater quantity or quality of grain, oil or other useful product when developed as
cultivar.
Ideotype Breeding: Ideotype breeding or plant type breeding can be defined as a
method of crop improvement which is used to enhance the genetic yield potential
through genetic manipulation of Individual plant character.
It aims to enhance genetic yield potential by modifying individual traits to their
predefined optimum levels. In ideotype generally morphological traits are included
but physiological, biochemical, anatomical and phonological traits should also be
included, wherever feasible.
C.M. Donald
4. IDEOTYPE OFWHEAT
1. A short strong stem - It imparts lodging resistance and reduces the losses
due to lodging.
2. Erect leaves - Such leaves provide better arrangement for proper light
distribution resulting in high photosynthesis or CO2 fixation.
3. Few small leaves - Leaves are the important sites of photosynthesis,
respiration and transpiration. Few and small leaf reduces water loss due to
transpiration.
4. Large ear - It will produce more grains per ear.
5. A presence of Awns - Awns contribute towards photosynthesis.
6. Single culm.
5.
6. IDEOTYPE OF RICE
● The concept of plant type in Rice was first introduced by
Matsushima in 1957, and later by Jennings (1964).
The Rice ideal or model plant type given by Jennings consists of
i. Semi dwarf stature.
ii. High tillering capacity.
iii. Short, erect, thick and highly angled leaves.
●
7. IDEOTYPE OF RICE
In 1969, Chandler proposed the ideotype of ‘dwarf rice’as follows –
1. Shorter culm length (100 cm or less).
2. Greater culm diameter
3. Lower relative internode elongation
4. Short erect leaves of medium width.
5. High tillering capacity.
6. More panicles/m2.
7. High (55% or more) harvest index.
8. IDEOTYPE OF RICE
● Janoria (1985) has suggested an alternative ideotype of rice that has been
developed to maximise utilization of available horizontal space and the
resources from the vertical space. The characteristic features of the novel
ideotype include -
1.Taller stature
2. Fewer, tough, non-lodging and all effective culms
3. Upright growth habit
4. Fewer, well spaced, thick, large but stiff leaves able to maintain
erect position
5. Heavy panicles with limited intra plant variation for panicle yield
6. High light transmission ratio and a deep, extensive root system.
9.
10. IDEOTYPE OF MAIZE
In 1975, Mock and Peace proposed ideal plant type of Maize.
1. Stiff-vertically-oriented leaves above the ear
2. Maximum photosynthetic efficiency
3. Efficient translocation of photosynthate into grain
4. Short interval between pollen shed and silk emergence
5. Small tassel size
6. Photoperiod insensitivity`
7. Cold tolerance
8. Long Grain-filling period.
11. In Sorghum improvement has been obtained through the use
of dwarfing genes. In this crop dwarf F1 hybrids have been
evolved which have made combine harvesting possible.
Swaminathan (1972) has listed several desirable attributes of crop
ideotypes with special reference to multiple cropping in tropics and
sub-tropics. These features consist of
1. Better protein quantity and quality.
2. Suitability to mechanization.
3. Photo and thermo insensitivity.
4. High productivity per unit of water.
12. 5. High productivity per day.
6. Crop canopies that can retain and fix maximum
of CO2.
7. Superior population performance.
8. Low photorespiration.
9. High response to nutrients.
10. High photosynthetic ability.
11. Multiple resistances to insects and diseases.
14. This ideotype was proposed by Singh and
coworkers in1974.
1. Plants of short stature (90-120 cm)
2. Compact and sympodial plant habit making
pyramidal shape.
3. Determinate fruiting habit with unimodal
distribution of bolling.
4. Short duration (150-165 days). It reduces cost of
crop management and allows double cropping.
5. Responsive to high fertilizer dose.
15. 6. High degree of interplant competitive ability. (It means the
ability to perform well at closer spacing, i.e. to use the
environmental resources efficiently.)
7. High degree of resistance to insect pests and diseases.
8. High physiological efficiency.
In addition, boll size is proposed to be in between 3.5 to 4 g,
and there should be synchrony of bolling in flush of flowering.
16. This ideotype was proposed by Singh and Narayanan in1993.
1. Short stature (75-80 cm) and compact plant habit.
2. Intermediate growth habit with at least two
monopodia.
3. Few smaller and thick leaves with spares hairiness.
4. Medium to big boll size (3.5 to 4 g).
5. Responsive to nutrients.
6. High degree of resistance to insects and diseases.
7. Synchronous bolling habit.
