Method for Leaf Area Determination in Chinese Potato (Plectranthus rotundifolius)

Abstract

A method for leaf area determination in Chinese potato (Plectranthus rotundifolius) was developed at Central Tuber Crops Research Institute, Thiruvananthapuram, India. There was significant positive correlation (r = 0.97) between length (L) and area (A) and breadth (B) and area (A) of leaf (r = 0.97). The factor (F) of relationship between L and A of leaf was 3.412 and that between B and A of leaf was 4.59. The relation between product of length and breadth (P) and A of leaf was also significant (r =0.99) and the F between P and A was 0.727. The linear regression equation between L and A, B and A and between P and A were Y = 5.949 x - 15.51, Y = 8.486 x - 17.81 and Y = 0.686 x + 1.114 respectively. The coefficient of determination (r2) values between L and A, B and A and between P and A were 0.948, 0.726 and 0.987 respectively. The coefficient of determination (r2) value observed between P and A near to 1 suggested that the regression equation was good fit. Therefore, using the F value derived from P, the total leaf area of a plant can be calculated by the formula: Total leaf area= P of a single leaf (average value of few observations) x 0.727 x total number of leaves per plant. The linear regression equation (y = 0.141 x + 7.833) and r2 value (r2 = 0.742) and significant positive correlation coefficient value (r = 0.861) between area and weight of dry leaf suggest that the dry leaf weight method can be also used for calculating leaf area of Chinese potato plant. The factor (F) derived between weight of dry leaf and area of leaf was 0.227. From the F value, the total area of a plant can be calculated by the formula: Total leaf area = weight of a single dry leaf (average of few leaves) x 0.227 x total number of leaves per plant.