Iron chlorosis resistance in dry bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata (L.) Walp.) : inheritance and marker-assisted selection /
Iron is essential for normal plant growth and development, and it is associated with many enzymes and proteins involved in photosynthesis and respiration. Iron deficiency in plants is manifested by a leaf yellowing or chlorosis. due to diminished chlorophyll synthesis. The primary cause of iron de...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739363861&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Iron is essential for normal plant growth and development, and it is associated with many enzymes and proteins involved in photosynthesis and respiration. Iron deficiency in plants is manifested by a leaf yellowing or chlorosis. due to diminished chlorophyll synthesis. The primary cause of iron deficiency is low solubility of Fe", which must be reduced to Fe 21 to be utilized by plants. Iron deficiency resistant plants induce genetically controlled biochemical reactions that make iron available in the usable form. Genetic differences for resistance have been found in bean and cowpea. I propose that molecular techniques, such as PCR and RAPDS, can improve the efficiency of and significantly accelerate breeding for iron chlorosis resistance. The objectives of the present investigation were to determine the genetic basis for resistance, and to identify RAPD markers associated with iron chlorosis resistance. Crosses between resistant and susceptible parents were made. Analysis of the F2 segregation patterns for greenness reconfirmed that 2 dominant genes are involved in the response to iron deficiency in bean, but the present study demonstrated that resistance is expressed when either dominant gene is present. A similar analysis in cowpea suggested that a single dominant gene confers susceptibility. Two DNA pools were constructed in both bean and cowpea and examined with 300 random primers. Analysis of polymorphisms allowed the selection of 28 RAPD markers, none of which was associated with iron deficiency resistance in bean. Eleven RAPD markers were assigned to 5 linkage groups and 17 markers were unlinked. In cowpea, the RAPD markers N7750 and 05800 appeared to be associated with the region controlling the iron deficiency response. These flanking markers could be simultaneously used for marker assisted selection of resistant genotypes. Three linkage groups were identified which included 16 of the 31 RAPD markers detected. Additional primers should be screened in order to assign the isolated markers to linkage groups, and to increase the probability of finding associations between RAPD markers and resistance to iron chlorosis in bean, and tighter associations in cowpea. |
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| Item Description: | Vita. "Major Subject: Plant Breeding". |
| Physical Description: | xi, 119 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 89-118. |