Fig. 1.

Leaf carbon isotope discrimination (δ¹³C) in field-grown plants. Diverse Spring (G) and Semi-Winter (SW) accessions of Brassica napus were grown in the field in Maricopa, Arizona, under irrigation. (A) Leaf tissue was collected prior to flowering, and δ¹³C was measured. A wide variation in δ¹³C was found between accessions. (B, C) δ¹³C of selected accessions including accessions with higher water use efficiency (G302) and lower water use efficiency (G284). Error bars denote the SEM. Statistical values for differences within categories were calculated using a one-way ANOVA followed by Tukey’s multiple comparisons test.