Previous work by our group developed transgenic cottonseed lines with elevated levels of oleic acid content (ranging from 20% to 35%; Chapman et al.,2001, JAOCS; 78: 941-47). These changes in fatty acid composition were accomplished through the introduction of a canola nonfunctional delta-12 fatty acid desaturase (FAD2), and were targeted for seed-specific expression via a phaseolin promoter. These transgenic lines consistently showed reduced seed germination, and pooled samples of T2 seed from these lines showed a marked reduction in seed oil content-- reduced from 20% oil by weight (in Coker 312 wildtype or null segregants) to about 12% oil by weight or lower in all seven independent transgenic lines examined. As anticipated, the severe reduction in embryo oil content resulted in decreased seed size and increased lint percent in transgenics. In addition, morphological analyses of mature seeds revealed a reduced accumulation of intracellular lipid bodies in cotyledon cells of transgenic lines, and severely disrupted cellular organization in lowest oil-containing seeds. Efforts by others to elevate oleic acid content in cottonseeds by FAD2-antisense suppression (Sunilkumar et al., 2005, Plant Biotech J 3: 319-330) or FAD2-RNA interference (Liu et al., 2002, Plant Physiol 129: 1732-1743) was not reported to lower seed oil content or affect seedling vigor. This suggests that altered oleic acid composition, per se, does not contribute to low cottonseed oil content or poor seedling performance, but instead points to the canola FAD2 allele as a possible mechanism for interfering with oil accumulation and subsequent seed germination. Future work is aimed at using these canola-FAD2 cottonseed lines to examine in detail the participation of FAD2 in seed oil biosynthesis and seedling performance.