“GENETIC DIVERGENCE, COMBINING ABILITY AND STABILITY FOR YIELD AND YIELD CONTRIBUTING TRAITS IN HYBRID RICE (Oryza sativa L.)”
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Date
2008
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
The present investigation was undertaken to identify the diverse parents in rice and
study the combining ability, heterosis and stability of experimental hybrids for yield and
yield components and to correlate genetic diversity of parental lines with standard heterosis
of experimental crosses.
During kharif, 2006 eighty six genotypes were evaluated for genetic diversity
at Research Farm, Directorate of Rice Research, Rajendranagar, Hyderabad. The analysis of
variance revealed significant differences among the genotypes for all the 13 characters
studied. Based on Mahalanobis D2 analysis the 86 genotypes were grouped into 10 clusters.
The pattern of distribution of genotypes into various clusters revealed that there was no
relationship between geographical distribution and genetic diversity. Greater genetic
divergence was found between clusters I and X, suggested exploitation of these two clusters
by intermating the genotypes in a definite breeding designs to explore the fullest range of
heterosis and to realize good recombinant lines. Based on genetic divergence studies, the
genotypes IR 45 and SG 26-120 from cluster I, CRMS 32B,GQ 25, GQ 70, APMS 6B, IBL
57, GQ 120 and 1005 from cluster II, IR 79156B and PUSA 5B from cluster IV, IR
58025B and SC5 2-2-1 from cluster V, IR 55, IR60 and BR827-35 from cluster VI, SG27-
77 from cluster VII , KMR3, 1096 and 612-1 from cluster VIII, GQ 37-1, 619-2, 517, 611-
1, 124 and SC5 9-3 from cluster IX and EPLT 109 and 118 from cluster X were selected
for hybridization programme as they were expected to produce high heterotic crosses .
Five CMS lines (viz., IR 58025A, IR 79156A, APMS 6A, PUSA 5A and
CRMS 32A) were crossed with twenty three restorers (viz., 1096, 1005, 619-2,612-1, 611-1,
GQ-25, GQ-37-1, GQ-70, GQ-120, KMR-3, IBL-57, BR827-35, EPLT-109, SC5 2-2-1,
SC5 9-3, SG27-77, SG26-120, 118, 124, 517, IR 43, IR55 and IR60) and the resultant 115
crosses along with the parents and four checks(viz., KRH2, PA 6201-hybrid checks ; Jaya
and IR 64-varietal checks) were evaluated for combining ability (Line X tester design),
heterosis and stability (Eberhart and Russel,1966) of the hybrids at three locations viz.,
Warangal, Hyderabad and Jagtial of Telangana region during kharif, 2007 .
The pooled analysis of variance for combining ability revealed significant
differences due to environments, parents, hybrids and various interactions indicating the
existence of wider variability in the material under studied. The ratios of GCA / SCA
variances revealed that non-additive gene action was predominant in the inheritance of days
to 50% flowering, plant height, flag leaf length, flag leaf width, productive tillers, spikelet
fertility per cent, 1000 grain weight, grain yield and per day productivity.
The gca effects of the parents in pooled analysis revealed that lines viz.,
APMS 6A, PUSA 5A and CRMS 32A and testers viz., 1096, 1005, GQ-70, KMR-3, IBL-57,
SG 27-77, SG 26-120 and 124 were found to be promising general combiners for grain yield
per plant and other traits. Based on significant sca effects, fifteen hybrids viz., APMS 6A x
GQ-25, PUSA 5A x IR 43, PUSA 5A x IR 55, APMS 6A x SC5 9-3, APMS 6A x 1005, IR
79156A x IBL-57, PUSA 5A x KMR-3, APMS 6A x 612-1, IR 58025A x GQ 37-1, IR
79156A x SG 27-77, IR 79156A x GQ-70, IR 79156A x KMR-3, IR 58025A x GQ-70,
APMS 6A x GQ-120 and IR 58025A x IR 60 were identified as promising for grain yield
per plant and other yield contributing characters.
Based on per se performance, sca effects and heterosis for yield and its
attributes in pooled analysis, five cross combinations viz., APMS 6A x 1005, PUSA 5A x
GQ-25, PUSA 5A x IR 43, APMS 6A x SC5 9-3 and PUSA 5A x KMR-3 proved to be
superior for yield and yield attributes.
Results of stability analysis revealed that six hybrids viz., CRMS 32A x 517,
APMS6A x 118, PUSA 5A x IR 55, PUSA 5A x 124, APMS 6A x GQ-120 and APMS 6A x
SG 27-77 are identified as stable and best performing hybrids for grain yield per plant and
other traits hence, suitable for wider environments. These hybrids also exhibited significant
positive sca effects, heterobeltiosis and standard heterosis along with per se performance for
grain yield per plant and other traits. Three hybrids PUSA 5A x 1096, IR 58025A x KMR-3
and CRMS 32A x GQ-120 performed well in favourable environments, whereas the hybrid
CRMS 32A x GQ-70 excelled in grain yield under poor environmental conditions.
A simple correlation worked out between JGT-SSRs based genetic diversity among
the parental lines and standard heterosis of the hybrids revealed that there is no significant
correlation between them. The main reason for non-significant correlation may be the lack
of linkage between genes controlling the traits measured and the markers used.
Based on the present study, it can be emphasized that CRMS 32A x 517, APMS 6A
x 118, PUSA x IR 55, PUSA x 124 and APMS 6A x GQ 120 are stable with the desirable
sca effects, heterosis and per se performance for grain yield and other important attributes.
These hybrids may be further tested over locations, seasons and years and recommended for
commercial release.
The three heterotic hybrids identified in the investigation viz., APMS 6A x 1005,
APMS 6A x SC5 9-3 and IR 79156A x SG27-77 have been included in station trial/
Initial Hybrid Rice Tri
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Keywords
GENETIC, DIVERGENCE, COMBINING, ABILITY, STABILITY, YIELD, YIELD, CONTRIBUTING, TRAITS, HYBRID RICE