Concept of Ideotype Breeding

Ideotype Breeding:

·???? Ideotype breeding was first proposed by Donald in 1968 working on wheat.

·???? Crop ideotype is model plant for specific environment

·???? It includes morphological, physiological and biochemical traits

Features of Ideotype breeding:

·???? Emphasis on individual trait

·???? It includes yield enhancing trait

·???? Exploits physiological variation

·???? Slow progress

·???? Selection

·???? Designing of model

·???? Interdisciplinary approach

·???? Continuous process

Crop Ideotype Features:

1.?? Wheat:

·???? Short strong stem

·???? Erect leaves

·???? Few small leaves

·???? Larger ear

·???? An erect ear

·???? Presence of awn

·???? A single culm

2.?? Rice:

·???? Semi dwarf stature

·???? High tillering capacity

·???? Short, erect, thick, highly angled leaves

·???? More panicles

·???? High harvest index (55 % or over)

·???? Physiological traits

3.?? Maize:

·???? Mock and Pearce (1975) proposed ideal plant type of maize

·???? Stiffed, vertically oriented leaves above the ear

·???? Maximum photosynthetic efficiency

·???? Efficient translocation of photosynthate into grain

·???? Short interval between pollen shed and silk emergence

·???? Small tassel size

·???? Photoperiod insensitivity

·???? Cold tolerance

·???? Long grain filling period

4.?? Barley:

·???? Rasmusson in 1987 suggested ideal plant type of six rowed barley with features:

ü Short stature

ü Long awns

ü High harvest index

ü High biomass

ü Kernel Weight

ü Kernel Number

5.?? Cotton:

·???? For Irrigated Cultivation:

ü Short Stature (90 – 120 cm)

ü Compact and sympodial plant habit

ü Determinate in fruiting habit

ü Short duration (150 – 165 days)

ü Responsive to high fertilizer dose

ü High degree of inter plant competitive ability

ü High physiological efficiency

6.?? Rainfed Cotton:

·???? Singh and Narayanan, 1993 suggested ideal plant type of rainfed cotton

ü Earliness (150 – 165 days)

ü Fewer small and thick leaves

ü Compact and short stature, indeterminate habit

ü Sparse hairiness

ü Medium to big boll size

ü Synchronous bolling

ü High response to nutrients

ü Resistance to insects, pests and diseases

Factors affecting Ideotypes:

·???? Crop species

·???? Cultivation

·???? Socio-economic conditions of farmers

·???? Economic use

Steps in Ideotype Breeding:

·???? Development of conceptual model

·???? Selection of base material

·???? Incorporation of desirable traits

·???? Selection of ideal plant type