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Title: Wide hybridization in the genus Vigna savi
Author: Sailan, Abdulla Abdulgabar
ISNI:       0000 0001 3545 385X
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 1991
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Wide hybridization in the genus Vigna savi was attempted utilizing wild relatives, cultivated and wild species. This investigation elucidated some imcompatibility barriers to interspecific crosses, between cultivated, wild relatives and wild species. The possibility of transferring gene(s) from wild relatives and wild species to the cultivated species was also investigated. Post-fertilization barriers existed between the Asian species that belong to subgenus Ceratotropis, while pre-fertilization barriers were found in the crosses between African and Asian species. Bridging crosses were attempted in order to overcome cross incompatibility. Pollen germination and pollen tube growth was studied mainly in crosses between African (V.unguiculata-cultivated) and Asian (V.umbellata-cultivated and V.glabrescens-wild). Pollen of African species were found not to germinate on stigmas of Asian species. However pollen of Asian species germinated on stigmas of African and penetrated style tissues for a maximum of 3 (mm) then ceased growth. Temperature and growth regulator treatments were used in order to improve pollen germination of African species on stigmas of Asian species, and pollen growth of Asian species in the styles of the African species. Some of these treatments initiated pollen germination but did not significantly improve pollen tube germination. Growth regulators applied to the pedicel were found to improve pod retention and allow further embryo development. Developed embryos were rescued in culture media for hybrid plants produced. These techniques were applied in crosses where post-fertilization incompatibility was found. In vitro pollination/fertilization techniques were attempted in order to overcome barriers between African and Asian species. Style pollination, ovary pollination, and placental pollination were used. No pollen germination was found on the style in all species used. In ovary pollination, some pollen germinated on cultured ovaries; increased pollen germination of African species was found when stigmatic exudate from African stigma was applied to the cut surface of the Asian ovary prior to pollination. Both media used for placental pollination maintained ovules for more than 4 weeks by which time the ovules had often increased in size. Placental pollination showed that pollen from both types germinated on both placental and part of the ovary cultured with ovule, but pollen tube growth was not sufficient to penetrate the micropyle.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Pollen germination