Fig. 2 Relationship between aboveground N content and green leaf area index at anthesis (r = 0.80, n = 23, P < 0.001), mid grain filling (r = 0.47, n = 25, P < 0.05), and maturity (r = 0.69, n = 21, P < 0.001) for nine sorghum hybrids grown under terminal water deficit. Total N content was the sum of green leaf N content, dead leaf N content, stem N content, and panicle N content. All graphs have less than 27 points, since at least one of these components was missing for a number of hybrids, preventing the calculation of total N uptake for those samples