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Biodiversity in pears (Pyrus spp) charecterization and conservation of Germplasm from Azad Jammu and Kashmir.

Ahmed, Dr. Maqsood (2009) Biodiversity in pears (Pyrus spp) charecterization and conservation of Germplasm from Azad Jammu and Kashmir. PhD thesis, Bahauddin Zakariya University, Multan.



A survey of five pear growing districts of Azad Jammu and Kashmir i.e. Rawalakot, Bagh, Muzaffarabad, Sudhnoti and Kotli was conducted during the year 2003 and 60 accessions of distinct characters of horticultural importance were selected from 48 sites of these districts for characterization. For each accession, passport data were collected with the help of Pyrus descriptor as developed by International Board of Plant Genetic Resources. During the next two years (2004 and 2005), all the selected accessions were visited thrice each year at the time of flowering, fruit setting and fruit maturity. Data were recorded on growth habit of plants, incidence of diseases (fire blight and apple scab), precocity, intensity of flowering, fruit setting, productivity, time of ripening, fruit shape and fruit colour. Leaves and fruit of these accessions were also collected and leaf area, fruit size and fruit weight were measured. Ripe fruit were evaluated for organoleptic parameters, nutritional value (TSS, total sugars and vitamin C content) and postharvest life at ordinary room temperature (26 ± 2 ºC). The accessions differed for these parameters; however, the accessions with the same local name had almost similar characteristics. All the accessions locally called as Frashishi and Desi nashpati had the excellent fruit quality and can be exploited for commercial production in the area. Most of the other accessions, also had good fruit quality except few (locally called as Btangi, Btung, Raj btung and Pathar nakh), which are mostly used as rootstocks in the area. The accessions were characterized by using protein markers based on bio-chemical analysis (SDS-PAGE). The accessions differed in number of bands which ranged from 12-20. According to the banding pattern the accessions were divided into the various groups and sub-groups showing similarities and differences among them. Out of sixty local accessions, fifty six accessions along with eight varieties (used as reference control) were also characterized using DNA based SSR markers to assess genetic diversity and relationship among them. Nine out of 12 primers revealed clear and reproducible amplification banding pattern in 41 genotypes (33 accessions and 8 control varieties). Cluster analysis based on UPGMA dendrogram, grouped the genotypes into clusters subclusters and groups on the basis of relatedness and variability. Most of the accessions were absolutely homogenous and were classified into two homogenous groups, despite the fact that these accessions differed in there morphological and physico-chemical traits. Attempts were also made to preserve the local pear germplasm through in vivo and in vitro methods. For in vivo preservation, a nursery was established and nine pear genotypes i.e. Khurolli, Bagugisha, Pathar nakh, Desi nakh, Kotharnul, Desi nash, Frashishi, Kashmiri nakh and Raj btung were propagated through whip grafting on Btangi seedlings. The genotypes differed for growth parameters. Apical shoots of nine pear genotypes (already mentioned above except Desi nash but including Btangi) were preserved in vitro under minimal growth conditions using low temperature treatments, modification in medium strength and adding mannitol in the basal medium and also by reducing the concentration of BAP and using growth retardants for different storage periods i.e. 3, 6, 9 and 12 months. The genotype differed significantly for survival and regeneration percentages. Storage at 5 °C, MS medium containing 2.5% mannitol and MS medium with reduced concentration of BAP (0.50 mg l-1) were found significantly better as compared to other treatments. Storage for the minimum period (3 months) was better than other storage periods as assessed on the basis of survival and regenerability of the cultures.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Biodiversity, Pears, Characterization, Conservation, ,Germplasm, Azad Jammu, Kashmir, Genetic, Diversity, organoleptic, parameters
Subjects:Agriculture & Veterinary Sciences(a)
ID Code:3024
Deposited By:Mr. Javed Memon
Deposited On:01 Jun 2010 12:27
Last Modified:26 May 2011 12:12

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