Browsing by Author "Wettasinghe, Ruwanthi"
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Item Development of castor (Ricinus communis) var. brigham with ultra low ricin content by analyzing soluble seed proteins(2012-08) Wettasinghe, Ruwanthi; Auld, Dick L.; Allen, Randy D.; Fokar, Mohamed; Abidi, Noureddine; Payton, Paxton R.Castor (Ricinus communis L.) is one of the oldest cultivated oil crops in the world. The unique oil produced in castor seeds contains ricinoleic acid, an essential specialty product that is widely used as a raw material in numerous commercial applications. In addition, the pressed cake of oil extraction is a value added by-product of animal feed and organic fertilizer industries. Also, castor seeds contain storage proteins that include ricin, a potent cytotoxin found only in the endosperm of the seed. Following oil extraction, ricin remains in the pressed cake which constitutes up to 5% of the dry matter. Ricin has been categorized as a potential bioterrorism agent by the United States Centers for Disease Control and Prevention hence, the presence of residual toxin in the byproduct hinders its usage as an animal feed and organic fertilizer in commercial applications. The purpose of this study was to identify castor var. Brigham seeds with low ricin content in each seed. This goal was accomplished by partial seed analysis and by image processing of an identified band that was recognized as ricin. Advance biotechnological strategies and tools utilized in this study, incorporated into castor breeding programs, may play a pivotal role in the development of castor var. Brigham with ultra low ricin content. Low ricin castor cultivars would eliminate the cost and time needed in ricin detoxification of pressed cake therefore, contributing to change human perception of the toxicity of castor and providing a global prospective to cultivate castor as an agronomically important crop.Item Investigation of random amplified polymorphic DNA (RAPD) as markers for soluble solids in onion(Texas Tech University, 1996-05) Wettasinghe, RuwanthiBulbing onions (Allium cepa L.) are one of the widely consumed vegetables in the United States. They are consumed fresh in salads, dehydrated to produce chips and powder which are used to enhance flavor of processed foods, and stored to use during the off-season. The multiple uses of onions are dependent upon the composition of soluble solids which are an economically important quality factor for both growers and processors. Typically, soluble solids in onion are improved using traditional breeding techniques which dependent upon selection. Selection based upon the phenotype is laborious and time consuming. Molecular markers have provided a valuable tool to improve the pace of selection in breeding programs. One such marker that is suitable to assist in the selection process in breeding is random amplified polymorphic DNA (RAPD). The purpose of this study was to investigate the utility of RAPDs as markers to screen for soluble solids in onion. This goal was accomplished by comparing four DNA extraction protocols and by contrasting two DNA polymerases to generate reliable RAPD profiles. Suitable protocol and polymerase were selected and were then used to generate and compare RAPD markers in two pooled DNA bulks which comprised of low and high soluble solids. DNA polymorphisms are generated and used as markers to tag and identify economically important traits such as soluble solids in onions. The application of RAPDs play a vital role in developing soluble solids onion cultivars.