Reciprocal Effects and Selection for Altered Fatty Acid Composition of Soybean Oil.

Abstract

ABSTRACT GILSINGER, JESSE JOHN. Reciprocal Effects and Selection for Altered Fatty Acid Composition of Soybean Oil. (Under the direction of JOSEPH W. BURTON)

This study focused on increased oleic acid content of soybean oil and consisted of three objectives: (1) to study maternal effects for fatty acid composition , (2) to study reciprocal effects for heritability and stability of increased oleic acid content, and (3) to examine how other traits are affected by selection for increased oleic acid content. Maternal effects were evaluated in 2005, 2006, and 2007 by analyzing reciprocal F1 seed resulting from crosses between the mid-oleic line N98-4445A and Dare, Haberlandt, Ogden, Arksoy, Midwest, and Peking. Reciprocal F1 seeds from a cross between the increased palmitic line N02-4441 and Dare were grown in vitro. The results showed that maternal effects for fatty acid composition were significant across a wide range of genetic materials and environments. Maternal effects for the F1 seed dissipated while differences between parents were maintained when grown in vitro. Reciprocal effects for heritability and stability were examined in twelve F2 derived populations over two years developed from reciprocal crosses between N98-4445A and Arksoy, Dare, Haberlandt, Midwest, Ogden, and Peking. Significant differences in heritability and stability between reciprocal populations were observed, suggesting it may be advantageous to make reciprocal crosses when developing populations for altered fatty acid selection in soybeans. To investigate selection for increased oleic acid content, two populations consisting of approximately 60 F4:6 lines were generated by crossing N98-4445A with the cultivars Dare and Tracy and planted as replicated trials at two North Carolina locations in 2006. Fatty acid composition, height, lodging, seed size, seed quality, yield, and maturity were measured for each plot. Plants were also genotyped with SSR markers. An increase in oleic acid was correlated with a decrease in yield and seed quality. Significant marker-trait associations for oleic acid content, seed quality, and yield were observed in both populations. These results demonstrate that these markers could be useful for marker-assisted selection for the mid-oleic trait across populations and could be used to improve seed quality and yield.