Allometric Model for Leaf Area Estimation in Black Pepper (Piper nigrum L.)

Abstract

Black pepper (Piper nigrum L.) is an important spice used in cooking and medicine. It is cultivated in more than 20 countries in Asia, Africa and Latin America. India is a major producer, consumer and exporter of black pepper. Leaf area (LA) is an indicator of crop growth and productivity. This study was undertaken to develop a method of estimating the individual LA of black pepper directly without the necessity for time-consuming area measurements. Ten black pepper lines were used in the study. Ninety matured leaves were collected from each line and an allometric relationship was derived bylogarithmic transformation between actual leaf area (ALA) measured using the electronic leaf area meter LI-3000 A (LI-COR, Inc., Lincoln, NB) and leaf length (LL). The correlation coefficient (r) between ALA and LL ranged between 0.8692 and 0.9644 and the standard error (S.E.) between 0.0822 and 0.1149. The allometric models for 10 lines were: Panniyur 1, LA¼0.7114 (LL)1.8409; Panniyur 2, LA¼0.3692 (LL)2.067; Panniyur 3, LA¼ 0.6148 (LL)1.8838; Panniyur 4, LA¼0.8355 (LL)1.7694; Sreekara, LA¼0.8984 (LL)1.6692; Subhakara, LA¼0.8384 (LL)1.738; Panchami, LA¼0.3691 (LL)2.0749; Pournami, LA¼0.4487 (LL)1.9718; Kottanadan, LA¼0.3474 (LL)2.0634; P-24, LA¼0.7579 (LL)1.654. These allometric models were used to calculate LA, which was then compared with the actual LA, and the correlation coefficient (r) between them was found to be > 0.99. These allometric models can be used to estimate the LA of individual leaves of black pepper. The approximate total LA of a vine can be obtained using following formula: total leaf area of black pepper vine (cm2) ¼ number of laterals per vine · number of leaves per lateral · leaf area of individual leaf.