physicochemical

J.Res. ANGRAU 39(1&2)28-33, 2011
COMBINING ABILITY ANALYSIS FOR YIELD AND YIELD COMPONENT TRAITS
IN RICE (Oryza sativa L.)
P. SAIDAIAH, M.S. RAMESHA, S. SUDHEER KUMAR and J.SURESH
Department of Genetics and Plant Breeding,
College of Agriculture, Acharya NG Ranga Agricultural University, Rajendranagar, Hyderabad – 500 030
ABSTRACT
One hundred and fifteen hybrids were developed utilizing Line (5 CMS lines) x Tester (23 testers) fashion.
The hybrids along with parents were evaluated for eight characters during kharif, 2007 at RARS, Warangal to
understand the gene action in rice. The combining ability analysis revealed significant differences among the
parents for all the characters studied indicating the predominance of dominance gene action in governing yield and
related traits. This suggests the possibility of exploiting heterosis. Two CMS lines (APMS 6A and CRMS 32A) and
six testers (1096, 612-1, GQ-70, GQ-120, KMR 3 and SG 27-77) were found to be good general combiners for yield
and other yield attributes. The hybrids APMS 6A x 612-1, PUSA 5A x KMR-3, CRMS 32A x IR 43 exhibited higher
specific combining ability with at least one of the parent possessing positive alleles for grain yield. The interrelationship
of sca with sca revealed that predominance of non additive gene action viz., additive x dominance and dominance
x dominance type for gene interaction for most of the hybrid combinations which could be exploited for heterosis
breeding programme in rice.
Substantial increase in rice (Oryza sativa L.)
production can be achieved only with the use of
suitable hybrids. This can be further hastened by
choice of suitable outstanding parents with favourable
alleles, which on crossing would give heterotic
hybrids. The line x tester analysis of combining ability
proposed by Kempthorne (1956) is the most common
method used to find out the general and specific
combiners and study the nature of gene action
governing the inheritance of different characters. The
main objective of this investigation was to identify
good general and specific combiners for yield and its
component characters.
MATERIALS AND METHODS
Five CMS lines viz., IR 58025A, IR 79145A,
APMS 6A, PUSA 5A and CRMS 32A were crossed
with 23 diverse elite restorers selected from rice
germplasm maintained at Directorate of Rice
Research (DRR), Hyderabad during rabi, 2006 using
line x tester design. The resultant 115 F 1
s and 28
parents were grown in Complete Randomized Block
Design with two replications during kharif, 2007 at
Regional Agricultural Research Station, Warangal,
Andhra Pradesh. Two hybrids (KRH 2 and PA 6201)
and two pure lines (Jaya and IR 64) were used as
standard checks. Twenty 25 days old seedlings were
transplanted at a spacing of 20 x 15 cm and all the
recommended agronomic practices were followed. In
each entry, five plants were selected randomly from
each replication and biometrical observations were
recorded for plant height, productive tillers per plant,
panicle length, panicle weight, filled grains per panicle,
spikelet fertility %, 1000 grain weight and grain yield
per plant. Days to 50% flowering was recorded on
plot basis. The mean data were analyzed for
combining ability following the standard method of
Kempthorne (1956).
RESULTS AND DISCUSSION
Presence of significant and high variance due
to genotypes for all the traits studied (Table 1)
indicated the existence of wide variability among the
genotypes. The combining ability variance of lines
and testers was significant for productive tillers per
plant and filled grains per panicle. In addition, the
lines for panicle weight, spikelet fertility, grain yield
plant -1 and productivity day -1 were also showed
significance. The high and significant mean squares
of lines x testers revealed that lines and testers
interacted and produced markedly different combining
ability effects and it might be due to wide genetic
diversity of lines and testers. The estimates of
variance due to SCA were much higher than that of
due to GCA variances for all the nine characters
revealing the importance of dominance and epistatic
Email: saidu_genetics@yahoo.co.in
28