Contents - Faperta

Evaluation of Transgenic Plants and Mapping Populations for Resistance to Insect Pests 71
where GYI UN and GYI IN are the grain yields of the Ith genotype under uninfested (GYI UN)
and infested (GYI IN) conditions, respectively.
Selection based on loss in grain yield favors genotypes with low grain yield potential.
High loss in grain yield indicates more sensitivity to insect infestation.
Relative Efficiency Index
The Relative Effi ciency Index (REI) can be calculated to classify genotypes based on grain
yield (Graham, 1984; Rosales-Serna et al., 2000) under infested and uninfested conditions.
REI ( GY _______ I (IN)
GY ) (IN)
( GY _______ I (UN)
GY (UN)
where GY I (IN) and GY (IN) are the grain yields of the Ith genotype and average grain yield of
the test genotypes, respectively, under insect infestation, while GY I (UN) and GY (UN) are the
grain yields of the Ith genotype and grain yield of all the test genotypes, respectively,
under uninfested conditions. REI favors the genotypes with high yield potential and tolerance
to insect damage.
Fischer and Maurer’s Stress Susceptibility Index
The Fischer and Maurer’s Stress Susceptibility Index (FMSSI) has been used for selecting
genotypes for drought tolerance (Fischer and Maurer, 1978), and can be used to categorize
the test genotypes for insect resistance as follows:
FMSSI 1 (GY ___________________
I (IN)/GY I (UN))
1 (GYIN/GY UN)
where GY I (IN) and GY I (UN) are the average grain yields of the Ith genotype under infested
and uninfested conditions, respectively, whereas GY IN and GY UN are the mean grain yields
of all the test genotypes under infested and uninfested conditions, respectively. Selections
based on FMSSI favors genotypes with low grain yield potential and high yield response
under insect infestation. FMSSI values 1.0 or 1.0 indicate high or low tolerance to insect
damage, respectively.
Fernandez Stress Tolerance Index
The Fernandez Stress Tolerance Index (FSTI) is based on grain yield reduction adjusted to
the severity of insect damage in a particular environment (Fernandez, 1993).
FSTI ( GY _______ I (IN)
GY ) (IN)
( GY _______ I (UN)
GY ) (UN)
( GY ______ (IN)
GY (UN)
where GY I(IN) and GY (IN) are the grain yields of the Ith genotype, and all the test genotypes,
respectively, under insect infestation, while GY I(UN) and GY (UN) are average grain yield
responses of the Ith genotype, and all the test genotypes, respectively, under uninfested
conditions. High FSTI values indicate high tolerance to insect damage and high grain yield
potential.
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