Year of Publication

2010

Degree Name

Doctor of Philosophy (PhD)

Document Type

Dissertation

College

Agriculture

Department

Plant Physiology

First Advisor

Dr. David Hildebrand

Abstract

Three oil crops, chia (Salvia hispanica L.), flax (Linum usitatissimum L.), and castor (Ricinus communis L.), were studied because of their nutritional and industrial values. Chia and flax are rich in an ω3 fatty acid, α-linolenic acid, and castor is a very high oil producer and high in a hydroxy fatty acid. Ethyl methanesulfonate (EMS) and gamma rays were employed to mutagenize chia seeds to produce early flowering mutants. The M1 population was grown and induced to flower by short-day photoperiods. The M2 population was planted in the field in Lexington, KY in 2008. Early flowering plants were found 55 days after planting while non-mutagenized plants did not produce any flower buds until the 7th of October, 82 days after planting, at a daylength of 11 hours and 32 minutes. 0.012% of the EMS-treated M2 population and 0.024% of the gamma radiation-treated population flowered much earlier than the controls. M3 early flowering mutant lines were able to flower at photoperiods of 12-15 hours in a greenhouse. Selected lines produced flower buds on the 7th of July, 47 days after planting, at a daylength of 14 hours and 41 minutes in the field in Lexington, Kentucky.

Different varieties of flax were evaluated for seed yield and field performance in Kentucky. Plant height and yield data were collected from three growing seasons. Yields from 2006 trial varied from 368-1,267 kg/ha. Yields from 2007 and 2008 were much lower due to drought. The variety ‘Carter’ gave the highest yield every season. Flax can be grown in Kentucky but yields are low.

Two high-yield castor varieties, ‘Carmencita’ and ‘TTU-LRC’, were crossed in greenhouse. The F1 population was grown in the field. Inflorescences were covered to ensure self-pollination. The F2 population showed a high degree of segregation for plant height, stem color, capsule color and seed yield in the following growing season. Data on plant height, number of branches, color, and yield was collected from 89 F2 individuals. Fifteen lines with the highest yield were selected to plant in the field in spring of 2009. New high-yield castor varieties are being developed for production in Kentucky.

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