PHENOTYPIC AND MOLECULAR CHARACTERIZATION OF THE LAND RACES OF PEARS CULTIVATED IN NORTHERN PAKISTAN

MOHAMMAD ISLAM, . (2015) PHENOTYPIC AND MOLECULAR CHARACTERIZATION OF THE LAND RACES OF PEARS CULTIVATED IN NORTHERN PAKISTAN. Doctoral thesis, HAZARA UNIVERSITY MANSEHRA.

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Abstract

Biosystematic treatment of 110 taxonomically unknown specimens collected from the land races of Pyrus trees available in nature and traditional farms of moist temperate region of Northern Pakistan is presented here. The landraces were surveyed in 100,565 Km2 area and best representative trees of different types were selected for morphological, DNA and ribosomal gene analyses. For morphological trait analyses, numerical parameters viz. petiole length, leaf area, pedicel length, fruit length, fruit width and fruit weight were considered. The morphological analyses sorted out all the collected specimens into 14 species viz., Pyrus pashia, P. calleryana, P. bretschneideri, P. pyrifolia, P. pseudopashiae, P. communis, P. sinkiangensis, P. hopeienses, P. serrulata, P. ovoidea, P. turcomanica, P. ussuriensis, P. xerophila and P. armeniacaefolia. Only two species i.e. P. pashia and P. communis were previously known from Pakistan. A substantial amount of genetic diversity was observed in all the land races with respect to all the parameters, except the leaf area. Mean values shows that the landraces Kushbago Batang (Kbb), Atti Bating (Ab) and Shardi Tanchi (Srt) had longer petioles with mean of 56 mm, 49 mm and 48 mm, respectively while the landraces Batangi and Glass Batang (Gb) had minimum values of 30.60 mm and 30.67 mm for petiole length, respectively. For pedicel length, landraces Batangi, Ghata Zira Tangai (Gzt), Klak Nak (Kn) Shardi Tanchi (Srt) had minimum value of 15-20 mm where as in Kushbago Batang (Kbb) a maximum pedicel length of 65.5 mm was recorded. For fruit length, Glass Batang (Gb) had the highest means (95.2 mm) followed by Kado Batang (Kb) and China batang with a mean of 73.1 mm and 72.2 mm, respectively. The land races Batangi, Gzt and Srt had the minimum fruit length. For fruit weidth, the land race Cb had highest (59.3 mm) value and the land races Batangi, Srt and Kzt had the lowest value of 23 mm, 23 mm and 25 mm, repectively while land races Kado batang (Kb) and Glass batang (Gb) proved similar in fruit width, 50.50 mm and 50.37 mm, respectively. The fruit weight was maximum in Cb and Gb which ranged from 148.0-163.7 g, followed by Kb, Kbb and Nhs while the minimum values were showed by land race Batangi, Srt, Kb and Kzt, ranging from 8.7-11.8 g. The numerical parameters like petiole length, pedicel length, fruit length, fruit width and fruit weight provides strong basis for the identification of Pyrus species and should be kept under consideration in taxonomic studies. For molecular characterizations a handy protocol for DNA isolation was optimized and tested on herbarium specimens using bark, wood and leaves, yielding 100, 68 and 53µg/µl quantity of DNA, respectively. The DNA yield was used both for marker assisted elaboration of the specimens and nucleotide sequencing of 18S RNA. PCR amplification of 36 landraces with 60 RAPD primers showed that only 28 primers successfully generated 304 reproducible bands, with the band sizes ranging from 150-2600 bp. The average bands per primer were 10.85 with 100% polymorphism. Fourteen among the primers showed land race specificity by producing 35 different size bands ranging from 150-2100 bp. Out of the 14 land race specific primers, 8 primers showed specificity to single land races with 1-2 loci. The primers D-16, K-09, J-05 and F-13 were specific to three different groups of landraces in the range of 4, 5 and 6, respectively. The homology tree based upon the reproducible bands categoriged all the 36 Pyrus landraces into 6 major groups with 62%-100% homology. The clustering pattern showed that most of the land races shared 80%-100% phylogeny and lineage similarity with each other. Results based upon 24 land races evaluated through 8S rRNA showed that Ktt was closely related to P. pyrifolia cv. Shinil, whereas Gtt occupied an intermediate position between P. pyrifolia cvs. Nijisseiki and Okusankichi. The accession Gzt showed its close relationship with P. pyrifolia cv. Mansoo, Zm showed its close relationship with P. communis cv. Clap's Favourite. Khan Tango was closely related to P. pyrifolia cv. Nijiseeki and P. pyrifolia cv. Okusankichi. The Pakistani Nashpati had close affinities with P. pyrifolia cv. Minibae. Parawoo Tango occupied an independent position in Pyrus sub clade I and Pekhawry Tango showed its close affinity with P. pyrifolia cv. Mansoo whereas the Pakistani land race Nak Tango showed its close resemblance with P. communis cv. Favorite. Asmasy Tango showed close relation with P. communis cv. Beurre. Mamosay-8 showed close relation with P. pyrifolia cv. Shinsui. Mamosay-12 occupied an intermediate position between P. pyrifolia cv. Miwang and P. communis cv. Conference, ?Mamosay Batal-14? showed the land race lies in between P. pyrifolia cvs. Shinsui and Niitaka. Mamosay-B15 showed close relation with P. communis cv. Clapps-Favourite. The Pakistani land race Gultar Tango was similar to P. communis cv. Clapp's Favorite. Hary Tango-Batal was closely related to P. communis cv. Clapp's Favorite. Kado Batang showed close resemblance with P. communis cv. Clapp's Favorite. The Pakistani land race of Malyzay Tango showed close relationship with P. communis cv. and Mamosranga showed close relationship with P. pyrifolia cv. Gamcheonbae. Guraky Tango showed close relationship with P. pyrifolia cv. Nijisseiki. Shaker Batang occupied an intermediate position in between P. pyrifolia cvs. Nijisseiki and Okusankichi. Similarly, the land race Pak-24 was in between the P. pyrifolia cv. Nijisseiki and Okusankichi. Shaker Tango proved to be closely related with P. communis cultivar Pachkan's Triumph.The biosystematics analysis of all the 110 specimens collected from northern Pakistan, added 12 new species to Pyrus from Pakistan. The study established phylogenetic relationship of Pakistani land races of pears with the recorded cultivars available in different parts of the world. We concluded that the land races Ktt, At, St and Pak-24 were hybrid in nature and their origin can be traced from their potential proginators as provided in their respective phylogentic trees.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: PHENOTYPIC,MOLECULAR,CHARACTERIZATION,LAND,PEARS,CULTIVATED,NORTHERN
Subjects: Q Science > QK Botany
Depositing User: Ms Maryam Saeed
Date Deposited: 25 Oct 2017 10:46
Last Modified: 25 Oct 2017 10:46
URI: http://eprints.hec.gov.pk/id/eprint/6699

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