To

2.  Those characters that enable a plant to
avoid, tolerate or recover from attacks
of insects under conditions that would
cause greater injury to other plants of
the same species
 R.H. PAINTER (Father of HPR)
 Those heritable characteristics possessed
by the plant which influence the ultimate
degree of damage done by the insect
 MAXWELL

3.  Ecological Resistance or Pseudo resistance
(Apparent resistance in susceptible hosts
due to environmental conditions)
 Host evasion
 Induced Resistance
 Escape

4.  Based on no. of genes
 Oligogenic/ Polygenic
 Major / minor gene resistance
 Based on biotype reaction
 Vertical resistance: against specific biotypes (specific
resistance)
 Horizontal resistance: against all the known biotypes (Non
specific resistance)
 Based on population/Line concept
 Pure line resistance
 Multiline resistance
 Miscellaneous categories
 Cross resistance
 Multiple resistance
 Based on evolutionary concept
 Sympatric resistance (Acquired by coevolution of plant and insect )
 Allopatric resistance (Not by co-evolution of plant and insect)

5.  Antixenosis (Non preference)
 Host plant characters responsible for non-
preference of the insects for shelter, oviposition,
feeding, etc
 Antibiosis
 Adverse effect of the host plant on the biology of
the insects and their progeny
 Tolerance
 Ability to grow and yield despite pest attack. Due
tto plant vigour, compensation by growth of
neighbouring plants

6.  e.g. Trichomes in cotton - resistant to
whitefly
 Wax bloom on carucifer leaves - deter
feeding by DBM
 Plant shape and colour also play a role in non
preference
 Open panicle of sorghum - Supports less
Helicoverpa

7.  Chemical factors
 DIMBOA (Dihydroxy methyl benzoxazin)- Against
European corn borer, Ostrinia nubilalis
 Gossypol - (Polyphenol) Helicoverpa armigera
(American bollworm)
 Sinigrin - Aphids, Myzus persicae
 Cucurbitacin Cucurbit fruit flies, Bactrocera sp.
 Salicylic acid Rice stem borer, Scirpophaga
incertulus
 Physical factors
 Thick cuticle, glandular hairs, silica deposits,
tight leaf sheath, etc.

8. ADVANTAGES
 Specificity
 Cumulative effect
 Eco-friendly
 Easily adoptable by farmers
 Less cost involved
 Compatability with other components
 Decreased pesticide application
 Persistence - durable resistance for long
periods

9. Disadvantages
 Time consuming - 3-10 years by traditional
breeding programmes to develop a resistant
variety
 Biotype development - new population
capable of damaging and surviving on plants
previously resistant to other population of
same species
 Genetic limitation