Victoria G. Benelli, Plant Science, University of Tennessee - Knoxville, Knoxville, TN and Fred L. Allen, Plant Sciences, University of Tennessee - Knoxville, Knoxville, TN
In the United States, niger (Guizotia abyssinica (L.f) Cass.) is primarily marketed as a seed of choice for American goldfinch (Spinus tristis) as well as other song and ground feeding birds because of its high oil content. In countries such as Ethiopia and India, niger is grown as an edible oilseed crop. The objectives of this study were to determine: (i) genetic variance, (ii) broad sense heritability, (iii) and gene effects using generation mean analysis of selected crosses. The traits analyzed included seed yield plant-1, seed number plant-1, branches plant-1, capitula plant-1, linoleic acid, oleic acid, and palmitic acid content. Fourteen niger plant introductions (PIs) of Indian, Ethiopian, and American origin were obtained from USDA/ARS germplasm collection at Pullman, WA. Ten replications of the 14 plant introductions were planted under field and greenhouse conditions at the East Tennessee Research & Education Center in Knoxville in August, 2012 using a completely randomized design. After initial assessments were made, 3 of the PIs were then selected for further evaluation, and crosses were made to produce four F1, eight BC, and four F2 populations. Seed were planted at the East Tennessee (2013 and 2014), Highland Rim (2013 and 2014), and Plateau (2014) Research and Education Centers. With the exception of seed yield, all traits had the greatest genetic variance in the F2 population. Results showed zero to moderate (0.00-0.44) broad sense heritability for all traits. Dominance gene effects were most influential on all traits. Epistatic gene effects were significant and had equal influence on traits as additive gene effects.