Morphological and Molecular Characterization of Native Dendrobium Orchid Species of East Siang District, Arunachal Pradesh
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Date
2022-07-16
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College of Horticulture and Forestry, Central Agricultural University, Pasighat -791102
Abstract
An investigation was carried out on “Morphological and Molecular Characterization of Native Dendrobium Orchid Species of East Siang District, Arunachal Pradesh”at Department of Floriculture and Landscape Architecture, College of Horticulture and Forestry, CAU (Imphal), Pasighat, Arunachal Pradesh during the year 2021-22. The experiment was laid out in Completely Randomised Design with 15 species (treatments) in three replications. The objectives of the investigation was to characterize the Dendrobium species based on DUS testing guidelines and to assess the genetic and molecular diversity amongst the species.
A total of 15 Dendrobium species were characterized for 52 traits by adopting DUS testing guidelines developed by PPV &FRA, New Delhi. Amongst these 21 measurable characters, 5 were monomorphic, 5 dimorphic and 11 polymorphic and out of 31 visuallyassessed DUS descriptors, 2 were monomorphic, 6 dimorphic and 23 polymorphic. Eight traits were identified for grouping of the species viz., plant height, internode number, inflorescence number per shoot, flower width in front view, flower predominant colour, lip predominant colour, lip colour pattern and flowering season.
The evaluation of 15 species for quantitative traits revealed that Dendrobium thyrsiflorum and Dendrobium densiflorum werefound promising for highest flower number per inflorescence (32.67 and 29.67 respectively), whereas, Dendrobium aphyllum and Dendrobium lituiflorum hadhighest number of inflorescence and can be used for hanging baskets. Dendrobium nobile (17.33 days) and Dendrobium nobile var. alba (15.67 days) were found promising for cut flower. Earliest flowering (February) was noted in Dendrobium lituiflorum andthe late flowering (May) was observed in Dendrobium wardianum. All the other species flowered during mid-season (March-April).The Dendrobium orchid species were divided into two groups based on hierarchical clusters of the quantitative traits, which is limited to principal component analysis.
The highest GCV and PCV values for flower number per inflorescenceare136.13% and 136.35%,respectively.Maximum heritability (99.74%) was observed in inflorescence length and the genetic advance was found highest in plant height (50.44); while genetic advance as percent of mean was noted to be highest in flower number per inflorescence (279.97%). Highest positive and significant genotypic correlation was exhibited in inflorescence number per plant by number of leaves (0.809) which specify the importance of the character in selection for improvement of flower yield. While positive phenotypic correlation on inflorescence number per plant was exerted by number of leaves (0.730) followed by internode number (0.675).
DNA extraction was carried out with CTAB method followed by PCR amplification using 25 SSR primers. Eighteen primers showed clear, bright amplicons and polymorphic in nature. The highest PIC (0.90) was shown by CXY09 followed by CXY08 and DOeSSR59 (0.89), respectively. The dendrogram was generated and the species were grouped into 3 major groups by using pooled binary data from SSR analysis.
Description
An investigation was carried out on “Morphological and Molecular Characterization of Native Orchid Species of East Siang District, Arunachal Pradesh” at Department of Floriculture and Landscape Architecture, College of Horticulture and Forestry, CAU (Imphal), Pasighat, Arunachal Pradesh during the year 2021-22. The experiment was laid out in Completely Randomised Design with 15 species (treatments) in three replications. The objectives of the investigation wasto characterize the Dendrobium species based on DUS testing guidelines, to assess the genetic and molecular diversity amongst the species.
A total of 15 Dendrobium species were characterized for 52 traits by adopting DUS testing guidelines developed by PPV & FRA, New Delhi. Amongst these 21 measurable characters, 5 were monomorphic, 5 dimorphic and 11 polymorphic and out of 31 visuallyassessed DUS descriptors, 2 were monomorphic, 6 dimorphic and 23 polymorphic. Eight traits were identified for grouping of the species viz., plant height, internode number, inflorescence number per shoot, flower width in front view, flower predominant colour, lip predominant colour, lip colour pattern and flowering season.
The evaluation of 15 species for quantitative traits revealed that Dendrobium thyrsiflorum and Dendrobium densiflorum werefound promising for highest flower number per inflorescence (32.67 and 29.67 respectively), whereas, Dendrobium aphyllum and Dendrobium lituiflorum hadhighest number of inflorescence and can be used for hanging baskets. Dendrobium nobile (17.33 days) and Dendrobium nobile var. alba (15.67 days) were found promising for cut flower.Earliest flowering (February) was noted inDendrobium lituiflorum andthe late flowering (May) was observed inDendrobiumwardianum. All the other species flowered during mid-season (March-April). Based on hierarchical clusters of the quantitative traits, the Dendrobium orchid species were grouped into two, which is confined to principal component analysis.