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Phenotypic assessment of sorghum (Sorghum bicolor L. Moench) germplasm reference set for yield and related traits under post flowering drought conditions

OAR@ICRISAT

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Relation http://oar.icrisat.org/3954/
 
Title Phenotypic assessment of sorghum (Sorghum bicolor L. Moench)
germplasm reference set for yield and related traits
under post flowering drought conditions
 
Creator Seetharam, K
 
Subject Sorghum
 
Description Sorghum reference set collection consisting of 384 accessions of five basic races,
10 intermediate races and five wild sub species was evaluated during 2008-09 (E1),
2009-10 (E2) post rainy season at ICRISAT, Patancheru, Andhra Pradesh and during
2009-10 at UAS, Dharwad (E3- Irrigated condition and E4 – Un-irrigated condition) and
RARS, Bijapur (E5- Un-irrigated condition). Data on seven qualitative and 11
quantitative traits were recorded to estimate the phenotypic diversity under post
flowering drought conditions and to identify the drought tolerant accessions.
The qualitative traits, white mid rib, pigmented plant, black and purple color
glume, one fourth glume covered, white, purple, and brown colored seeds occurred in
high frequencies in the sorghum reference set. These traits are useful markers since they
are associated with economically important traits such as increased fodder quality,
resistance to grain mould, preference in food and beverage industries.
Variance due to genotypes (σ2g) and genotype X environment (σ2ge) interactions
were significant for all the 11 quantitative characters and variance due to genotype X
drought interaction was significant for panicle exerstion, panicle length, panicle width
and grain yield. The seven flowering groups differed significantly for days to 50 per
cent flowering and plant height. The basic races and intermediate races as group differed
significantly from the wilds for panicle weight, grain yield and 100 seed weight. Grain
yield of entire reference set had significant positive correlation with panicle weight, 100
seed weight but had negative correlation with days to 50 per cent flowering, plant height
and basal tillers in all the environments. Principal component analysis in entire reference
showed that, nine characters in E1, E2 and its pooled and eight characters in E3, E4, E5
and its pooled were important in explaining the variation. Shannon-Weaver diversity
(H') index was high for plant height, 100 seed weight, grain yield, panicle weight,
SPAD1 and SPAD2 in entire reference set , in all the flowering groups, basic races,
intermediate races and wilds. Average phenotypic diversity index was similar in all the
environments. On the basis of phenotypic dissimilarity between pair of accessions, ten
pairs of most diverse accessions under drought conditions were identified. These
accessions could be used in breeding programs for selecting superior lines in segregating
population and for the development of mapping population. The hierarchical cluster
analysis grouped five basic races, ten intermediate races and five wild sub species into
three clusters in E1, E2, E4 and pooled over E1 and E2, two clusters in E3, five clusters
in E5 and four cluster in pooled over E3, E4 and E5.
Based on drought tolerance indices such as STI, MP, GMP, SSI, TOL and DTE a
total of 65 drought tolerant accessions were indentified representing the entire reference
set and seven flowering groups. Twenty nine accessions based on E1, E2 pooled and 22
accessions based on E3, E4 and E5 pooled were identified for high SCMR. Accessions
identified based on drought tolerance indices and with high SCMR were predominantly
from the race caudatum which was early flowering, had shortest plant height, high
panicle weight and grain yield. In addition to this, best twenty accessions were identified
for each of the traits, days to 50 per cent flowering, plant height, panicle length, 100 seed
weight, panicle weight and high grain yield. These diverse trait specific promising
accessions have the potential for their utilization in breeding programs for developing
improved sorghum cultivars with a broad genetic base. The information on phenotypic
diversity and trait specific accessions provided valuable baseline knowledge for further
progress on the selection and breeding for drought tolerance in sorghum.
 
Date 2011
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://oar.icrisat.org/3954/1/Thesis_Seetharam.pdf
Seetharam, K (2011) Phenotypic assessment of sorghum (Sorghum bicolor L. Moench) germplasm reference set for yield and related traits under post flowering drought conditions. PhD thesis, Tamil Nadu Agricultural University.