Combining ability analysis was done using 10 fine-aromatic rice genotypes in a partial
diallel crossing design to estimate General Combining Ability (GCA), Specific
Combining Ability (SCA) and nature of gene· action to heip in breeding fine-aromatic
rice varieties. Ctmsiderable variation among parents and crosses (F1s) for agronomic
parameters were observed The .parental mean for panicle weight (g) was 2.83 g while
the F1s was 3.16 g with an average heterosis of 0. 3 g (11. 3%) and a maximum heterosis
of 3.17 g (112.0%). Panical weight (g) being the important yield component was
analysed to estimate GCA, SCA and gene effects. The analysis of variance revealed
significant effects (P=0.01) due to GCA and SCA. The GCA estimates of parents
ARC10863 (0. 77) and IR43850 (0.33) were significant and positive, while those of ARC
10796 (-0.20) and Khumal-4 .(-0.28) were significant (P=0.01) Q!ld negative. The
superior crosses with hi~h positive effect on panicle weight were from the abo~e parents.
The additive variance (cl A) estimate was 0.30 and that of dominance variance (rl D) was
3. 79, thereby indicating low genetic he"itability (0. 064), and presence of both additive
and non-additive gene effects on·panicle weight of fine-aromatic rice. Implications of
this study in the selection of superior parents and crosses, developing suitable breeding
strategy and approaches for increased effectiveness and efficiency in breeding have
been discussed

Combining ability analysis was done using 10 fine-aromatic rice genotypes in a partial
diallel crossing design to estimate General Combining Ability (GCA), Specific
Combining Ability (SCA) and nature of gene· action to heip in breeding fine-aromatic
rice varieties. Ctmsiderable variation among parents and crosses (F1s) for agronomic
parameters were observed The .parental mean for panicle weight (g) was 2.83 g while
the F1s was 3.16 g with an average heterosis of 0. 3 g (11. 3%) and a maximum heterosis
of 3.17 g (112.0%). Panical weight (g) being the important yield component was
analysed to estimate GCA, SCA and gene effects. The analysis of variance revealed
significant effects (P=0.01) due to GCA and SCA. The GCA estimates of parents
ARC10863 (0. 77) and IR43850 (0.33) were significant and positive, while those of ARC
10796 (-0.20) and Khumal-4 .(-0.28) were significant (P=0.01) Q!ld negative. The
superior crosses with hi~h positive effect on panicle weight were from the abo~e parents.
The additive variance (cl A) estimate was 0.30 and that of dominance variance (rl D) was
3. 79, thereby indicating low genetic he"itability (0. 064), and presence of both additive
and non-additive gene effects on·panicle weight of fine-aromatic rice. Implications of
this study in the selection of superior parents and crosses, developing suitable breeding
strategy and approaches for increased effectiveness and efficiency in breeding have
been discussed