Effect of cytoplasm and cytoplasmicnuclear interaction on downy mildew resistance in pearl millet (Pennisetum glaucum (L.) R. Br.)
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Date
2014
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Publisher
CCSHAU
Abstract
Forty eight hybrids and their parents of pearl millet were evaluated to study the effect of
cytoplasm and cytoplasmic- nuclear interaction on downy mildew (S. graminicola) disease resistance.
Genotype mean squares were highly significant for all the characters studied indicating high variability
among genotypes. The non-significance of A×R vs. B×R hybrid comparisons for downy mildew
incidence revealed that downy mildew is not affected by the cytoplasm. Higher/ equally good number
of cytoplasmic effects for various characters in case of A4 and A5 CMS system lines revealed that these
lines should be used extensively in breeding programme. The preponderance of magnitude of fixed
effect variances due to sca revealed that non-additive gene effects governed the inheritance for almost
all the characters except downy mildew. The studies on combining ability revealed that none of the
parents– lines (sterile as well as maintainer) and tester proved to be good general combiner for all the
characters. The line 4 (81B1) representing A1 system fertile cytoplasm (maintainer) combined favorably
for grain yield, dry fodder yield and effective tillers. The tester G73-107 combined favourably for
downy mildew resistance. The hybrid 3×11 (81A5×ERC) combined for grain yield and other important
traits and also expressed significant positive sca with high per se performance. The same hybrid
expressed significant positive heterosis for grain yield, effective tillers, panicle girth, harvest index and
downy mildew resistance (negative heterosis) both at 30 days and 60 days. This cross combination
3×11 (81A5×ERC) needs further vigorous testing. The molecular analysis of parental lines by SSR
markers (twenty six) exhibited monomorphic pattern for all lines indicating the genetic purity of lines.
The study emphasizes on continued and sustained efforts on the cytoplasmic as well as genetic
diversification of seed as well as pollen parents.
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Keywords
Diseases, Hybrids, Cytoplasm, Millets, Yields, Environment, Crossing over, Developmental stages, Heterosis, Biological phenomena