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GENETIC DIVERGENCE IN COTTON (Gossypium hirsutum L.)

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Title GENETIC DIVERGENCE IN COTTON (Gossypium hirsutum L.)
 
Creator ESWARA RAO, G
 
Contributor CHENGA REDDY, V
 
Subject GENETIC, DIVERGENCE, COTTON
 
Description The present investigation was carried out during kharif, 2007-2008 at
Regional Agricultural Research Station, Lam Farm, Guntur with 60 genotypes of
cotton (Gossypium hirsutum L.) to study the genetic variability, heritability,
genetic advance as per cent of mean, genetic divergence, character association and
the magnitude of direct and indirect effects of yield component traits with seed
cotton yield in respect of 16 characters viz., plant height (cm), days to 50%
flowering, number of monopodia per plant, number of sympodia per plant, number
of bolls per plant, boll weight (g), ginning out-turn (%), seed index (g), lint index
(g), 2.5% span length (mm), micronaire (10-6g/in), bundle strength (g/tex),
uniformity ratio (%), fibre elongation (%), lint yield per plant (g) and seed cotton
yield per plant (g).
The genotypic coefficients of variation for all the characters studied were
lesser than the phenotypic coefficients of variation indicating the masking effect of
the environment. Number of monopodia per plant, number bolls per plant, lint
yield per plant and seed cotton yield per plant exhibited moderate to high
variability. High heritability coupled with high genetic advance observed in the
case of number of monopodia per plant and lint yield per plant indicate the
predominance of additive gene action and hence, simple selection might play a
role to some extent. High heritability coupled with moderate genetic advance was
observed in case of plant height, 2.5% span length and seed cotton yield per plant
revealing the role of both additive and non additive gene action. The other traits
viz., number of sympodia per plant, number of bolls per plant, boll weight, seed
index and uniformity ratio showed moderate heritability and low genetic advance
indicating major role of non additive gene action.
The correlation studies revealed that plant height, number of sympodia
per plant, number bolls per plant, boll weight, seed index, lint index, micronaire,
uniformity ratio, elongation and lint yield per plant had significant positive
association with seed cotton yield per plant. The path coefficient analysis
revealed that plant height, days to 50% flowering, number of monopodia per
plant, number of bolls per plant, seed index, lint index, uniformity ratio, and lint
yield per plant exerted direct positive effect on seed cotton yield per plant.
Selection based on these attributes may be helpful in evolving high yielding
varieties of upland cotton.
The results of multivariable analysis resulted in random distribution of 60
cotton genotypes into fourteen clusters in case of D2 analysis and into eight
clusters in case of principal component analysis was at random indicating no
relation between genetic diversity and geographical diversity. Based on the intra
and inter- cluster distances among the groups, suggestions were made to attempt
crosses after confirming their general combining ability between cluster VIII
(CPD 787) and cluster X (CNHO 12), followed by cluster XIII (GISV 218) and
cluster XIV (CSH 3047) to obtain better and desirable segregants.
Principal component analysis identified six principal components (PCs),
which contributed 78.21 per cent of cumulative variance. The population with
high PC1 values were characterized by high number of monopodia per plant and
bundle strength whereas, population with high PC2 values were characterized by
lint yield per plant and number of bolls per plant. In PC3, characters like 2.5% span
length and elongation showed maximum weightage.
Therefore, major emphasis should be laid on selection process with more
number of bolls per plant and simultaneous selection of other traits viz., boll
weight, seed index, number of sympodia per plant and lint index for realizing
higher seed cotton yield with desirable fibre quality.
 
Date 2016-08-02T10:37:38Z
2016-08-02T10:37:38Z
2008
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/70463
 
Language en
 
Relation D8375;
 
Format application/pdf
 
Publisher ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD