2008 A P P L I E D A N D N A T U R A L S C I E N C E F O U N D A T I O N ANSF JANS Journal of Applied and Natural Science 9 (1): 274– 279 (2017) Effect of plant spacing and fertility level on leaf area variation at different phenological stages of cape gooseberry (Physalis peruviana L.) grown in sodic soil Angrej Ali 1* and B. P. Singh 2 1 Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Wadura Campus, Sopore-193201 (J&K), INDIA 2 Department of Horticulture, Narendra Dev University of Agriculture and Technology, Kumarganj, Faizabad - 224229 (UP), INDIA *Corresponding author. E-mail: anghort@gmail.com Received: January 28, 2016; Revised received: October 26, 2016; Accepted: January 26, 2017 Abstract: Vegetative and reproductive growth in cape gooseberry ( Physalis peruviana L.) proceed concomitantly during the greater part of the life cycle thereby foliar traits (e.g. leaf area) become important in photosynthetic action of the plant. In present study, the leaf area variation in cape gooseberry was studied at five phenological stages i.e. pre-flowering (30 DAT), start of flowering (60 DAT), early fruiting (120 DAT), peak fruiting (180 DAT) and late fruiting (240 DAT), grown at three spacings (60 × 75, 75 × 75 and 75 × 90 cm) and four NPK levels (control, 60:40:40, 80:60:60 and 100:80:80 kg ha -1 ). Leaf area increased from per-flowering (73.51 cm 2 ) to start of flowering (82.26 cm 2 ) and thereafter, it was decreased gradually at later stages i.e. early fruiting (79.17 cm 2 ), peak fruiting (73.15 cm 2 ) and late fruiting (60.21 cm 2 ). Spacing had no significant effect on leaf area at pre-flowering and start of the flowering, but at later stages, widest spacing (75 × 90 cm) exhibited significantly maximum leaf area at early fruiting (82.44 cm 2 ), peak fruiting (78.22 cm 2 ) and late and fruiting (65.31 cm 2 ). Leaf area increased due to increased NPK levels with maximum values under 100:80:80 kg NPK ha -1 at all the phenological stages: pre-flowering (78.99 cm 2 ), start of flowering (90.97 cm 2 ), early fruiting (88.47 cm 2 ), peak fruiting (80.74 cm 2 ) and late fruiting (67.22 cm 2 ). Spacing × NPK Interactions was significant only at peak fruiting and late fruiting stages with maximum leaf area (75.22 and 71.02 cm 2 , respectively) at 75 × 90 cm + NPK @ 100:80:80 kg ha -1 . These findings can be further helpful in leaf sclerophylly studies in cape gooseberry. Keywords: Cape gooseberry, Leaf area, NPK, Phenological stage, Physalis peruviana L., Spacing INTRODUCTION Morphomertic monitoring of crops plants during the growing season becomes increasingly important in order to adjust the crop husbandry and to provide in- formation for obtaining optimum yield. In growing crop canopies, foliar traits such as leaf area index and leaf mass per unit area are the important factors in leaf light harvesting capacity and photosynthetic potentials. Leaf area of crop is one of the most important parameter required in the estimation of several plant growth indices and various models for predicting crop growth and dry matter production, development rate, yield potential, radiation use efficiency (Centritto et al., 2000; Williams and Martinson, 2003), quantifying crop-weed competition, energy and water exchanges in the plant soil-atmosphere continuum, as they are associated with photosynthesis and evapo-transpiration (Guo and Sun, 2001). Leaves of the same canopy often show different rates of photosynthesis and transpiration, therefore, estimations of leaf area linked to physiological characteristics are essential to define the overall contribution of each canopy portion to fruit quality and ISSN : 0974-9411 (Print), 2231-5209 (Online) All Rights Reserved © Applied and Natural Science Foundation www.jans.ansfoundation.org yield (Serdar and Demirsoy, 2006; Ribeiro and Macha- do, 2007). Apart from genetic potential of the crop, the growing environments have profound effects on crop develop- ment resulting in modified overall canopy structure and appearance. Altering the soil fertility by providing balanced nutrition as per the crop requirements is one of the easiest ways to boost up crop productivity. A reliable supply of nitrogen, phosphorus and potassium is crucial and especially significant for synthetic events within growing cells. Leaf expansion is particularly sensitive to nutrient supply (especially nitrogen, phosphorus and potassium), primarily to the needs of enlarging cells for synthesis of new materials and generation of turgor. Leaf area and vertical L profile influence the interception and utilization of solar radiation of crop and consequently, the dry matter production (Boote et al., 1998). Better correlation appeared between leaf areas and weights at the high nitrogen rate than at the low nitrogen rate (Miller et al., 1967). Since the interception in the supply of major nutrients even for a brief period is determined by pattern of crop growth and development which may