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00000ctm a2200000Ia 4500 |
| 001 |
in00000088545 |
| 005 |
20220104090732.0 |
| 008 |
820730s1981 xx bm 000 0 eng d |
| 035 |
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|9 AAK5385AM
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|a (OCoLC)08646412
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|a (OCoLC)8646412
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|a (OCoLC)ocm08646412
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| 040 |
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|a TXA
|b eng
|c TXA
|d OCLCQ
|d OCLCF
|d OCLCO
|d OCLCQ
|d UMI
|d TXA
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| 049 |
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|a TXAM
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| 099 |
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|a 1981
|a Disser-
|a tation
|a T917
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| 100 |
1 |
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|a Tuleen, Darlene Mae.
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| 245 |
1 |
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|a Screening, selection and evaluation of gamma irradiation-induced mutants of Zea mays L. for resistance to southern corn leaf blight.
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| 264 |
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|c 1981.
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| 300 |
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|a xi, 101 leaves ;
|c 29 cm
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| 336 |
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|a text
|b txt
|2 rdacontent
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| 337 |
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|a unmediated
|b n
|2 rdamedia
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| 338 |
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|a volume
|b nc
|2 rdacarrier
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| 500 |
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|a "Major subject: Plant Pathology."
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| 500 |
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|a Typescript (photocopy).
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| 500 |
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|a Vita.
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| 502 |
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|b Ph. D. in Philosophy
|c Texas A & M University
|d 1981
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| 504 |
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|a Includes bibliographical references (leaves 82-95).
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| 520 |
3 |
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|a The maternally inherited pollen-sterility character used prior to 1970 in commercial production of maize (Texas male-sterile system) conditions a hybrids' reaction to Bipolaris (Helminthosporium) maydis race T. Although certain hybrids and inbreds are more susceptible than others, any Texas male-sterile cytoplasm (cms-T) is more susceptible than its counterpart in the wild type, or normal, cytoplasm. Genes which restore pollen fertility, do not change this cytoplasmic susceptibility. The objective of this study was to induce durable and effective resistance to the disease caused by this organism, southern corn leaf blight, in an agronomically useful genetic background. Kernels of the cms-T version of an inbred with restored fertility, Tx441Rf, were exposed to four dosages of gamma-irradiation from ('60)Co. Dosages were subsequently evaluated for their efficiency and effectiveness in producing chlorophyll mutations. Both efficiency and effectiveness increased with increasing dosage based on the biological criteria used in calculations. First generation (M(,1)) plants were self-pollinated and their progeny evaluated for resistance to southern corn leaf blight. M(,2) and M(,3) seedlings were screened for resistance in a field trial (natural infection) in 1979 and in the greenhouse (controlled inoculation) in 1981. Intense selection pressure was applied in controlled inoculations with B. maydis race T by providing ideal conditions for disease development. Progeny of two resistant selections from the field trial exhibited resistance following the controlled inoculation. Four additional putative mutants with superior resistance were selected from among inoculated M(,2) seedlings. These resistant variants were evaluated in family studies where the frequency of chloroplast defects and viviparous mutants in the irradiated population was recorded. Success in the prescribed genetic manipulation of an agronomically important plant species can served as a prototype and speed progress in attaining disease resistance in maize and other crops. Our present understanding of this host-parasite interaction and mitochondrial membrane permeability is advanced by the discovery of phytotoxicity to s-triazine herbicides in cms-T maize. In vivo and in vitro studies demonstrated a greater sensitivity to atrazine and simazine for certain cms-T inbreds than for inbreds in normal cytoplasm.
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| 650 |
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|a Corn
|x Disease and pest resistance.
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| 650 |
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0 |
|a Plant mutation breeding.
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| 650 |
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0 |
|a Plants
|x Effect of gamma rays on.
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| 650 |
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4 |
|a Plant Pathology
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| 655 |
|
7 |
|a Academic theses
|2 lcgft
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| 700 |
1 |
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|a Bockholt, Anton J.,
|e degree committee member.
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| 700 |
1 |
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|a Frederiksen, Richard A.,
|e degree supervisor.
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| 700 |
1 |
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|a Smith, James D.,
|e degree committee member.
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| 700 |
1 |
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|a Toler, Robert W.,
|e degree committee member.
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| 710 |
2 |
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|a Texas A & M University,
|e degree granting institution.
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| 856 |
4 |
1 |
|u http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=749776811&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD
|z Link to ProQuest Copy
|t 0
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| 856 |
4 |
1 |
|u https://hdl.handle.net/1969.1/DISSERTATIONS-98875
|z Link to OAKTrust copy
|t 0
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| 994 |
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|a C0
|b TXA
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| 999 |
f |
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|s 2037d739-4c97-3355-a57a-01b911c6f348
|i a5300522-2de3-3930-939b-a72c010a9c5f
|t 0
|
| 952 |
f |
f |
|p noncirc
|a Texas A&M University
|b J.J. Pickle Campus
|c High Density Repository
|s HDR
|d Remote Storage
|t 0
|e 1981 Dissertation T917
|h Other scheme
|i unmediated -- volume
|m A14841003909
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| 952 |
f |
f |
|a Texas A&M University
|b College Station
|c Electronic Resources
|s www_evans
|d Available Online
|t 0
|e 1981 Dissertation T917
|h Other scheme
|
| 998 |
f |
f |
|a 1981 Dissertation T917
|t 0
|l Remote Storage
|
| 998 |
f |
f |
|a 1981 Dissertation T917
|t 0
|l Available Online
|