Seed yield was 6 to 28 times more variable than chemical characters (oil, protein, iodine number). Use of incomplete block designs and other considerations justified long, narrow plots. Total cost (in hours) was 39.0% for obtaining yield and 61.0% for chemical attributes. Optimum plot size, apportioning cost among characters, was 3.2 times the basic unit ( 8 × 2 feet). Yield required 33, 50 and 700 times more replication than oil, protein and iodine number for comparable precision.