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Study of the interrelationship of important traits contributing to the resistance of shoot fly in Sorghum bicolor (l.) moench

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Title Study of the interrelationship of important traits contributing to the resistance of shoot fly in Sorghum bicolor (l.) moench
 
Creator Vijayalakshmi, K
 
Subject Sorghum
Entomology
 
Description Investigations on the interrelationships of important traits that
contribute to shoot fly (Atherigona soccata Rondani) resistance in sorghum
genotypes selected earlier empericaily for shoot fly resistance were carried
out at the International Crops Research Institute for the Semi-Arid Tropics
(ICRISAT), Patancheru, Andhra Pradesh, India in the 1991 -92 postrainy and
1992-93 rainy seasons in shoot fly infested and uninfested conditions.
The experiment was conducted in completely randomised block design
with ten tall and ten dwarf genotypes originating from the same pedigree or
pedigrees of related parents. Data recorded on various morphological,
agronomic traits and shoot fly resistance parameters (percentage plants with
eggs, number of eggs/100 plants, deadheart percentage) were subjected to
statistical analyses to estimate mean performance, genetic variances for
different traits, the direct and indirect effects of various morphological, and
agronomic traits on shoot fly parameters.
Emperical selection for shoot fly resistance and grain yield was
effective as the tall lines, SPSF 1128 and 1169 and the dwarf lines, SPSF
1170 and 1101 in the postrainy season, and the tall lines, SPSF 1029 and
11 18, and the dwarf lines SPSF 1014 and 1126 in the rainy season showed
shoot fly resistance with desirable grain yield. Grain yield under infestation
was reduced by 14 per cent in the talls, and 18 per cent in the dwarfs in the
postrainy season, while the reduction was 70 per cent in the talls, and 61 per
cent in the dwarfs in the rainy season when compared to the yield potential
under uninfested condition. The talls were superior (12 per cent in infested
and 7 pe cent in uninfested condition) to the dwarfs in the postrainy season.
while the dwarfs were superior (25 per cent in infested, and 3 per cent in
uninfested condition) in the rainy season.
Shoot fly infestation with infestor rowtfish meal technique was
extremely high in rainy season and moderate in postrainy season.
Heritabilities for various traits and their genetic gains were high under
moderate (about 85 per cent deadhearts in the susceptible checks)
infestation. The tall genotypes were slightly more vigorous and glossy and
had long, broad, and droopier leaves with more dense trichomes and higher
ovipositional preference (in postrainy season) than dwarf genotypes. At
maturity dwarfs were significantly short compared to tall genotypes while
there were no differences in their heights in the early stage of development
in both the seasons.
Path analyses indicated that selection should aim to reduce drooping
depth (perhaps without reducing leaf lengh,tf, and increase glossiness
intensity and early plant height in talls to further enhance the levels of shoot
fly resistance. In dwarfs, increasing trichome density, glossiness intensity
and leaf length (without increasing droopiness or reducing early plant height)
would be desirable. However, the correlations and heritability studies
indicated that undue emphasis should not be placed on increasing trichome
density (in dwarfs) or reducing the leaf droopiness (in talls) to increase shoot
fly resistance as this might lead to reduced grain yields. Therefore, the traits
shown to be neutral such as glossiness, early plant height and vigour should
be given more emphasis in the selection in both talk and dwarf groups.
Thus, the study showed the need to have separate selection schemes
to breed dwarf (female) lines and tall (restorer) lines in sorghum.
 
Date 1993
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://oar.icrisat.org/675/1/60750.pdf
Vijayalakshmi, K (1993) Study of the interrelationship of important traits contributing to the resistance of shoot fly in Sorghum bicolor (l.) moench. PhD thesis, Andhra Pradesh Agricultural University.