Relationships between extractable chlorophyll and SPAD values in muskmelonleaves

Chlorophyll content of muskmelon is usually determined by destructively sam pling plant leaves. However, a hand-held SPAD-502 Chlorophyll Meter provide s rapid and nondestructive measurements of leaf chlorophyll content. This s tudy aims to determine the relationships between extractable chlorophyll an d SPAD values in muskmelon leaves. SPAD readings were significantly related to extracted chlorophyll of muskmelon leaves both on a fresh weight and le af area basis. Quadratic equations best described their relationships. At 1 0 days after nitrogen (N) fertilization, the r(2) values for chlorophyll a, b, and total chlorophyll on a fresh weight basis were 0.84, 0.86, and 0.85 , respectively, while on a leaf area basis, r(2) values were 0.92, 0.95, an d 0.94, respectively. At 17 days after fertilization, the r(2) values, for chlorophyll a, b, and total chlorophyll on a fresh weight basis were 0.57, 0.49, and 0.56, respectively, while on a leaf area basis, r(2) were 0.72, 0 .67, and 0.71, respectively. Therefore, the SPAD-502 Chlorophyll Meter can be used to measure chlorophyll content of muskmelon leaves.