Morpho-molecular diversity analysis of wild species of rice (Oryza spp.) for yield traits and blast resistance
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Date
2022-12-02
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Palampur
Abstract
The present investigation entitled “Morpho-molecular diversity analysis of wild species of rice (Oryza spp.)
for yield traits and blast resistance” was conducted at CSK HPKV, Palampur (H.P.). Thirty accessions of
wild rice (Oryza nivara, Oryza barthii, Oryza glaberrima and Oryza meridionalis) and cultivated rice (Oryza
sativa) procured from School of Biotechnology, Punjab Agriculture University Ludhiana were grown in RBD
with two replications to study morphological and molecular diversity in wild species for yield and yield
contributing traits and to identify resistant sources for rice blast.
Analysis of variance revealed sufficient variability among all the test accessions except for kernel length,
kernel breadth and length breadth ratio. High PCV and GCV were observed for grain yield/plant followed by
harvest index. Moderate PCV and GCV were observed for plant height, tillers/plant, number of
branches/panicle, spikelets/panicle, spikelet fertility(%), biological yield/plant and 1000-grain weight. High
heritability coupled with high genetic advance was observed for number of spikelets/panicle, harvest index
and grain yield/plant. Grain yield/plant exhibited significant positive correlation with panicle length, number
of branches/panicle, spikelets/panicle, spikelet fertility(%), biological yield/plant, 1000-grain weight, harvest
index, kernel breadth, milling(%) and head rice recovery(%). Path analysis revealed that high positive direct
effects were shown by harvest index followed by biological yield/plant. Genetic diversity studied using
Mahalanobis D2
statistics, grouped 30 rice accessions into seven diverse clusters. Maximum inter-cluster
distance was observed between cluster VI and V followed by cluster V and III. Divergence studies indicated
that the two accessions of O. nivara (W124, W234) and one accession each of O. glaberrima (W8) and O. sativa
(HawaoM), respectively may be used as a suitable parents in future hybridization programme. At molecular level,
16 SSR primers amplified 41 polymorphic alleles with an average of 1.78 alleles/primers. Cluster analysis of
SSR data grouped the accessions into six major clusters. Genetic diversity based on D2
statistics revealed that
twenty accessions showed correspondence results with molecular diversity analysis. Disease reaction showed
that one accession each of O. barthii (W53), O. meridionalis (W1001), O. sativa (HawaoM) and seven accessions
of O. nivara (W116, W118, W144, W226, W234, W268, W308) were found resistant to all the three diseases
(blast, false smut and brown spot) and field screening for blast resistance, two accessions of O. glaberrima
namely, W2 and W8 showed resistance and exhibited resistant gene i.e., Pi9 195 and Nbs2 Pi9. O. nivara
accessions showed desirable characteristics like early flowering, early maturity, high biological yield/plant,
grain yield/plant, harvest index and long kernel length; O. glaberrima accessions showed early maturity, long
flag leaf length, good spikelet fertility(%), 1000-grain weight, high harvest index and good kernel breadth; O.
barthii accessions showed early maturity, long panicle length and good spikelet fertility(%) and O.
meridionalis accessions had good biological yield/plant. Different accessions of wild species showed
superiority for various test traits that directly and indirectly affects the grain yield. Thus, these accessions can
be employed in pre-breeding programmes for rice breeding.