Tuesday, November 14, 2006

Cytoplasmic Effects on Fatty Acid Stability and Maternal Effects in Glycine Max.

Joseph Burton and Jesse Gilsinger. "USDA-ARS, NC State Univ.", 3127 Ligon Street, Raleigh, NC 27607, United States of America

Cytoplasmic and maternal effects on fatty acid composition in soybean (Glycine max (L.) Merr.) are being investigated.  In recent years, there has been a major effort to produce soybean lines with modified unsaturated fatty acid profiles in order to improve quality and develop new uses for soybean oil.  Several studies have shown significant genotype × environment interaction for unsaturated fatty acid composition of soybean lines with various fatty acid profiles.  The differences in fatty acid content are likely due to the different weather conditions from year to year and location to location.  Due to the high level of genotype × environment interaction, heritability estimates are often low making breeding for altered fatty acid composition somewhat cumbersome.  To date, at least six unique cytoplasmic groups have been described in G. max as revealed by restricted fragment length polymorphism (RFLP) analysis. Whether or not cytoplasm type affects soybean oil composition stability across environments is currently being investigated using the mid-oleic soybean line N98-4445A.  Maternal effects for fatty acid composition in soybeans are also being investigated. It is believed that most maternal effects are not heritable and only a reflection of the environmental effect during seed development since the seed-filling period depends on nutrients the plant transports to the seed. However, to rule out possible within seed genetic factors, maternal effects on fatty acid composition are being studied using real time PCR to examine the expression of a mutant and wild type gene in F1 soybean seeds exhibiting maternal effects for 16:0.  Maternal effects are also being studied by examining the growth and maturation of these F1 seeds In vitro. Results of these studies will be presented.