Contents - Faperta

138 Biotechnological Approaches for Pest Management and Ecological Sustainability
Sorghum
Resistance to the sorghum shoofl y, A. soccata is controlled by additive effects, and is
expressed as a partially dominant trait at low to moderate levels of infestation (Rana,
Jotwani, and Rao, 1981; Dhillon et al., 2006a). The additive component increases at high
infestation, but the dominance component is unaffected (Borikar and Chopde, 1980).
However, P.T. Gibson and Maiti (1983) reported that resistance is expressed as a recessive
trait conditioned by a single gene. Additive effects control the expression of resistance to
the spotted stem borer, C. partellus (R.S. Pathak and Olela, 1983). Additive gene effects
govern resistance to leaf feeding and stem tunneling, while resistance to deadheart formation
is controlled by a nonadditive type of gene action (R.S. Pathak, 1990). Additive
type of gene action controls leaf feeding and deadheart resistance to spotted stem borer,
C. partellus, while resistance to tiller production and exit holes is governed by additive
and dominance effects, while resistance to stem tunneling is governed by dominance
type of gene actions (Sharma et al., 2007). Sorghum resistance to greenbug, S. graminum
biotype C, was fi rst detected in Sorghum virgatum (Hack.) Stapf. Resistance in the sorghum
genotype SA 7536 is inherited as an incompletely dominant trait (Weibel et al., 1972).
Resistance to biotypes C, E, F, and I is inherited as an incompletely dominant trait controlled
by a few major genes (Weibel et al., 1972; Puterka and Peters, 1995; Tuinstra, Wilde,
and Krieghauser, 2001). Resistance to the sorghum midge, S. sorghicola from AF 28 is
inherited as a recessive trait, and is controlled by two or more loci (Boozaya-Angoon
et al., 1984, Rossetto and Igue, 1983), and by additive gene effects (Widstrom, Wiseman,
and McMillian, 1984; H.C. Sharma et al., 1996, 2000), which varies across locations
(H.C. Sharma, Mukuru, and Stenhouse, 2004). However, resistance to sorghum head bug,
C. angustatus, is inherited as a partially dominant trait controlled by both additive and
nonadditive gene action (H.C. Sharma et al., 2000b), while resistance to the African head
bug, Eurystylus oldi (Poppius) is largely controlled by the additive type of gene effects
(Ratnadass et al., 2002; Aladele and Ezeaku, 2003). Expression of resistance in the F1 hybrids is infl uenced by cytoplasmic male sterility, and resistance is needed in both parents
to produce sorghum hybrids with resistance to shoot fl y, A. soccata, sugarcane aphid,
M. sacchari, midge, S. sorghicola, and head bug, C. angustatus (H.C. Sharma et al., 1996,
2005c, 2004; Dhillon et al., 2006a, 2006b).
Cotton
Most of the characters associated with resistance to bollworm, H. armigera, in cotton are
governed by oligogenes, and can be transferred into locally adapted cultivars. Growth and
development of H. armigera was considerably reduced on some of the male sterile lines of
cotton (Natarajan et al., 1985). Inheritance of gossypol-containing glands in cotton, which
is associated with resistance to bollworms is due to the G 13 allele (Calhoun, 1997). Diallel
analysis has indicated that the additive type of gene effects account for approximately 90%
of the total genetic variance in cotton for resistance to the tobacco budworm, Heliothis
virescens (Fab.), and number of gossypol glands (Wilson and Lee, 1971; Wilson and Smith,
1977). Wilson and George (1979, 1983) evaluated the combining ability for resistance to
seed damage by pink bollworm, Pectinophora gossypiella (Saunders), and observed that gene
action contributing to resistance in progeny was additive, and only a few genes conditioned
resistance. Trichome density in Gossypium species, which is associated with resistance to
the leaf hopper, A. biguttula biguttula, has been associated with fi ve genes referred to as t 1–t 5
(Lacape and Nguyen, 2005).