ESTIMATION OF GENE ACTION, COMBINING ABILITIES AND HETEROSIS IN Grewia optiva Drummond
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Date
2013
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Abstract
ABSTRACT
The present investigation entitled “Estimation of gene action, combining abilities and heterosis in Grewia optiva
Drummond” was carried out in the Department of Tree Improvement and Genetic Resources, Dr Y. S. Parmar University of
Horticulture & Forestry Nauni, Solan (HP) during 2010-2012. There is collection of Grewia optiva genotypes from different
districts of Himachal Pradesh and were maintained in the nursery from which ten genotypes was included in the study and
the plant material of 6 females (SO-1, SO-2, SO-4, SO-8, CH-2 and SI-15) and 4 male (SO-3, SI-6, BI-4 and HA-4)
genotypes were control crossed using Line X Tester (6X4 factorial) mating design. Out of twenty four controlled crosses
attempted all the crosses successfully produced viable seeds. The per cent successful crosses was highest in SO-2 X SO-3 (
88.10 %) and minimum was for SO-8 X HA-4 (23.81 %). Maximum seeds per flower (3.80) was recorded for SO-8 X HA-4.
Maximum germination percentage (72.72) was recorded for crosses involving SI-15 X BI-4 (70.59), survival percentage was
in SO-1 X BI-4 (97.73 per cent) recorded highest per cent survival, while, CH-2 X BI-4 (57.69 per cent) recorded lower
survival per cent. GCA variances were highly significant for seed diameter, seed length, germination per cent, survival per
cent, nursery characters like plant height, collar diameter, number of leaves, internodel length and leaf area. Higher
magnitude of SCA variances as compared to GCA variances for collar diameter (six months) and fodder quality characters.
SO-8 the female parent genotype was proved to be good general combiners for all nursery characters, male parents BI-4
expressed its positive general combining ability for plant height, collar diameter (for two months data) and number of leaves
per plant. SI-6 and SO-3 showed positive general combining ability for collar diameter while SI-6 and BI-4 for internodel
length. For fodder quality parameter, SO-8 and SO-4, while SI-6 and BI-4 were good general combining ability with respect
to crude protein content. The F1 SO-4 X HA-4 recorded positively significant SCA effects for most of the parameters. The
genetic components of variance in F1 generation revealed that dominance components (H1 and H2) and additive component
(D) were highly significant for all the characters. The regression line exhibited that most of the characters were controlled by
dominance and over dominance type of gene action. Over dominant gene action with low to high narrow sense and broad
sense heritability was observed for many character studied. For nursery characters, SO-8 and SI-6 showed over dominant
gene action for plant height, collar diameter with high broad and narrow sense heritability. In SO-8 X SI-6 over dominant
gene action was observed for plant height, collar diameter and number of leaves. For fodder quality characters SI-15 X BI-4
gave the highest positive significant SCA effects for crude protein content. From Wr/Vr graph maximum dominant gene
action for nursery character were observed in SO-1, SO-2, SI-15,CH-2 and SO-4 and for fodder quality character, female
parent CH-2, SO-8 and SI-15and male genotype SO-3, SO-8 and HA-4 exhibited over dominant gene action for crude
protein, crude fat and nitrogen free extract. SI-15 X BI-4 showed higher mid parent heterosis for plant height (49.06 %), SO-
8 X BI-4 expressed its heterotic ability for collar diameter (98.63 %) and Internodel length (46.63 %). Whereas, SO-8 X SI-6
cross showed higher heterosis for number of leaves (23.16), leaf area (122.57 %), leaf weight (171.56), crude protein content
(35.77 %) and crude fiber (19.52 %). The paternity analysis using molecular markers disclosed the fact that F1’s are highly
similar to their male parents. The 14 RAPD markers data showed that 23 out of 24 hybrids were highly similar to their male
parents, whereas, eleven ISSR markers disclosed that 20 out of 24 hybrids were highly similar to their male parents.
Description
Keywords
hybrids, biological phenomena, crossing over, genes, heterosis, genetics, exhibitions, genotypes, planting, rapd, Grewia optiva Drummond.