Figure 12.20 The proportion of incident radiation intercepted by potato canopies as a function of leaf area index. The different symbols indicate agronomic treatments over two growing seasons. In 1979: □ cv. Record, ○ cv. Pentland Crown. In 1980: cv. Pentland Crown with three treatments (see text): ●Treatment 1, ▲Treatment 2, ■ Treatment 3. (Based on Khurana and McLaren 1982)