Fitness of full-sib apomictic and sexual progeny of buffelgrass /
Breeding apomictic grasses is based on either the direct
| Main Author: | |
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739668081&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Breeding apomictic grasses is based on either the direct selection of apomictic land races or the selection of elite apomictic F, hybrids from crosses between sexual and apomictic plants. The development of sexual cultivars has not been attempted in apomictic species because sexual plants are rare and believed to have inferior fitness when compared to apomictic land races or hybrids. The fitness of sexual and apomictic progeny was investigated in this study. The S, and F, progeny segregating for method of reproduction and the parents (apomictic male and sexual female) were established in 1994 and 1995 to study the vegetative and reproductive fitness of sexual and apomictic plants. The F, progeny showed 39% and 38% heterosis over the mid-parent value for forage yield and seed set, respectively. Forage yield of the F, progeny suggested that sexual hybrids were as vigorous as their apomictic counterparts. Inbreeding depression was observed in the S, population with forage yield and seed set being 40% and 75% less than the sexual parent, respectively. Low seed production in sexual plants and the severe inbreeding depression in S, progeny may explain the low frequency of sexuality in apomictic species. The construction of an RFLP map was initiated using heterogeneous DNA probes. Nine linkage groups were identified for the sexual parent and five for the apomictic parent using single dose DNA restriction fragments. While the DNA markers clearly demonstrated polyploidy of buffelgrass, the limited number of DNA markers did not permit the determination of the nature of polyploidy or allow the detection of associations between selected phenotypes (method of reproduction, inflorescence type and rhizome) and RFLP markers. |
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| Item Description: | Vita. "Major Subject: Plant Breeding". |
| Physical Description: | ix, 69 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 41-48. |