Genetics of
Resistance to Pink
Stem Borer Attack in
Flint Maize
Populations
A. Butrón, P. Soengas, P.
Revilla, A. Ordás, and
R.A. Malvar
Misión Biológica de
Galicia
Introduction
• Pink stem borer is the main pest
in northwestern Spain
Average yield losses = 15%
Ear damage
Stem damage
Plant Breeding is one of the means
that can be used in a pest integrated
control system
Introduction
Life cycle of Sesamia
nonagrioides Lef.
Larva
Eggs
Pupa
Moth
Introduction
• Previous studies have identified
sources of resistance and
determined the genetics involved
• Nevertheless, resistance of flint
maize populations has not been
fully prospected
Objective: to test the variability
for resistance to pink stem borer
attack among flint maize
populations and to determine the
genetics involved
Introduction
• Local flint maize varieties
supply:
– Early vigor
– Early flowering
– Lower stem lodging
– Relative resistance to drough
stress
– High quality flours
Material and
methods
Diallel among 10 flint maize
populations
Population
• Gallego
• Gallego/Hembrillla norteño
• Norteño
• Norteño largo
• Basto/Enano levantino
• Fino
• Tremesino
• Relámpago 8 hileras
• Amarillo precoz de Simone
• Longfellow
Origin
North
North
North
North
East
Center
South
Argent.
Argent.
USA
Material and
methods
• Diallel was tested in 1998
and 1999
• Randomized complete block
designs
• Ten plants/plot were infested
with Sesamia nonagrioides
eggs
• Tunnel length to estimate
stem damage
• General appearance of the
ear to estimate ear damage
(1-9)
• Analysis II of Gardner and
Eberhart (1966)
Material and
methods
Analysis II (Gardner and Eberhart,
1966)
– Yij = µv + 1/2(vi + vj) + hij
»Yij = observed mean of the
cross of varieties i and j
»µv = mean of all varieties
»vi and vj = variety effects
»hij = observed heterosis
– hij =  (h +hi + hj + sij)
Results
Analysis of variance of the
diallel
Source
of variation
TL
GA
Population
Variety
Heterosis
P x Year
*
*
NS
NS
*
*
NS
NS
* Significant at the 0.05
probability level.
Results
Variety effects = difference between a
paticular variety mean and the mean of
all varieties
Population
TL
GA
Gallego
Gallego/Hn
Norteño
Norteño largo
Fino
Basto/El
Tremesino
Longfellow
Relámpago
Simone
LSD
-5.7
-5.6
1.5
2.2
10.5
-23.6
-6.3
0.5
10.0
16.6
16.5
-0.95
-0.33
-0.50
-0.50
0.75
-0.12
0.97
0.15
0.42
-0.03
1.12
Conclusions
Additive gene effects were
the most important effects
 Variability for stem
resistance was larger than
variability for ear resistance
Basto/Enano levantino could
be the base material in a
recurrent selection program