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dc.contributor.authorBlischak, Leslie Anneen_US
dc.date.accessioned2014-03-14T20:41:23Z
dc.date.available2014-03-14T20:41:23Z
dc.date.issued2005-07-06en_US
dc.identifier.otheretd-07132005-154708en_US
dc.identifier.urihttp://hdl.handle.net/10919/33989
dc.description.abstractGametophytic selection was examined as a breeding tool in developing Phalaenopsis hybrids that are more cool or warm temperature tolerant. Two hybrid Phalaenopsis, P. (Taisoco Windian à Sogo Sogo Yukidian) by P. hybrid unknown, were reciprocally cross-pollinated and exposed to 14°C/9°C for 7 days as a cold pollination treatment. Plants were pollinated again and exposed to 30°C/25°C for 3 days for the warm pollination treatment. Each cultivar was placed in either of two growth chambers during the pollination treatments and exposed to the selected temperatures, an 11-h photoperiod with an irradiance of 180 Mmol⠢m-2⠢s-1 and a relative humidity of 70%. The plants were returned to the greenhouse after pollination and the green capsules were collected after 150 days. Seeds obtained from these treatments were surface-sterilized and equal volumes were placed on Phytamax® medium. Evaluation of protocorm development was done after 73 days on a thermogradient table ranging from 10 to 30ºC. For the first family for which reciprocal crosses were available, the number of protocorms per plate ranged from 0 in the coldest treatments to 290 at 28°C. For cold pollinated seeds, protocorm development was optimum at 22 and 28°C (means of 290 and 250 protocorms per plate, respectively) whereas the greatest protocorm development for warm pollinated seeds occurred at 20°C (103 protocorms per plate). Of the 1471 total protocorms obtained 1095 were from cold pollinations, whereas 376 were from the warm pollinations. Protocorms were evaluated for leaf and root formation 125 days after initial plating. Transfer to warm or cold incubators occurred as protocorms developed leaves and roots. Seedlings were finally transferred to dried sphagnum and placed in growth chambers set to original pollination temperatures. One year after initial plating seedlings were evaluated on the following criteria: wet weight, number of leaves, leaf area, number of roots, and root length. The pollination treatment significantly affected the number of roots per seedling whereas germination temperature during germination significantly affected the weight (g). Weight of the seedlings, number of roots and the average root length were significantly affected by the interaction between pollination treatment and germination temperature. The weight, number of leaves, and average root length were significantly affected by the interaction between pollination treatment and incubator/growth chamber. These differences indicated that seedlings derived from warm pollination were more vigorous under warm growing conditions and those derived from cold pollination were more vigorous under cold growing conditions. The significance of the interaction between pollination treatment and incubator/growth chamber indicates that gametophytic selection for thermotolerance in Phalaenopsis can be successfully used as a plant breeding tool. Additional replication is required to confirm the greater germinability of seed derived from pollination occurring over a greater range of temperatures.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartthesisphalaenopsis.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectPhalaenopsisen_US
dc.subjectOrchidaceaeen_US
dc.subjectmale gametophytic selectionen_US
dc.subjectthermotoleranceen_US
dc.subjectgametophyteen_US
dc.titleGametophytic Selection for Thermotolerance in Phalaenopsisen_US
dc.typeThesisen_US
dc.contributor.departmentHorticultureen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
dc.contributor.committeechairVeilleux, Richard E.en_US
dc.contributor.committeememberNiemiera, Alexander X.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07132005-154708/en_US
dc.contributor.committeecochairNowak, Jerzyen_US
dc.date.sdate2005-07-13en_US
dc.date.rdate2012-05-08
dc.date.adate2005-08-18en_US


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