INTRODUCTION

1.1 Background of the study

Mango (Mangifera indica L.), one of the species among the 73 genera of the family Anacardiaceae in order of Sapindals, is important tropical fruit in the world. It is also known as “King of the fruits” (Purseglove, 1972). It originates from the Ushongo Local Government region, with 41 recognised mango species, which originate as a resinous and fibrous forest tree (Mukherjee, 1951 and 1967). In Nigeria, Mango grown on an area of 2500 thousands ha, with production of 18002 thousands M. tons, and productivity of 7.2 MT/ha.

Leaf area index is defined as the estimated area of leaves over a unit of land (m2/ m2), so one LAI unit means 10,000 m2 of leaf area per hectare. The amount of leaves in the canopy of the plant is one of the essential ecological characteristics generally quantified by the leaf area index (LAI). LAI is one of the principal driving forces of net primary photosynthesis, use of water and nutrients and carbon equilibrium. It is an important variable used for the prediction of primary photosynthetic development and evapo-transpiration. In theoretical ecology of development, LAI plays a key role. Light interception is directly related to the overall dry matter production of a number of crops (Duncun et al., 1973) which is also ideal for fruit trees (Jackson and Palmer, 1977). Efficient light distribution within the foliage and its interaction with various parts is critical to maximizing photosynthetic activity, flower bud development and colour development (Rajan and Lal, 1999). Leaves are an active medium of energy, carbon and water exchange among tree canopies and the atmosphere. Assimilate production depends on the area of the leaf and its light exposure, expressed by the volume of the canopy, the density of the leaf and the interception of the leaf light. The Leaf Area Index (LAI) which regulates certain physiological processes, including evapo-transpiration, photo- synthesis, etc. can be used to define the leaf canopy component (Villalobos et al., 1995). The leaf area index in coincidence with sunlight interception is useful as a basis for analyzing canopy productivity (Fischer, 2011).

Photosynthesis is probably the mechanism most observed and modelled, not least because of its direct influence of CO2 on the photosynthetic pace. Leaf area index varies with many variables (e.g. recurred climate, water and nitrogen availability and a certain level of CO2) (Drake et al., 1997). Latest investigations have shown that canopy photosynthetic activity increases with the leaf area index (Rochette et al., 1995). The Leaf Area Index (LAI) measures the quantity of leaf quantifiable in the ecosystem, imposing essential controls on photosynthesis, respiration, rainfall and other processes that connect plants to the environment

1.2 Statement of the problem

Mango farmers who do not properly manage branch growth run the risk detriment of quality and harvest volume. The resulting unattractive appearance disqualifies the fruit from the export market due to stringent quality requirements. Producers get low returns from such blemished fruits as the fruits are sold in the local market and to local juice processors. Effect of fruit position on the uncultured branch tree changes and quality of the mango and these problems resulted in low fruit yield. 

1.3 Objective of the study

The general objective of this study is to determine number of mango branches produce per plant. The specific objectives of this study are:

1. To determine the relationship between branch number (m3), Leaf area index and yield of the mango

2. To determine the relationship between leaf area index and yield per tree of mango

3. To determine the relationship between plant branch number and yield per tree of mango