Too old to mango?
How does the age of a mango tree affect the quality of the fruit?
Background
Mango has been called the king of fruits and India produces more than 20 million tons of mango each year, more than 40% of the world’s mango. Each year the harvest season, from April to July, marks the start of summer across the country for a nation of a billion people and mangos are part of history, culture, and big business alike. There are more than 1000 varieties of the fruit grown across India. Unsurprisingly, there is much research into the production of mangos.
There are many factors that affect the quality of mango fruit at harvest. Factors such as irrigation, soil, rootstock, nutrients, and pest management all influence the final product harvested from a mango tree and these have been studied within India and beyond. Mango growers have long known that the quality of the fruit changes over time, but there has been little scientific research to explore this phenomenon.
Exactly how does the age of a mango tree affect the quality of the fruit?
Dataset
Researchers at the Indian Agricultural Research Institute (ICAR) in New Dehli sought to answer this question with Amrapali mangos (Mangifera indica). These data were collected at the ICAR experimental farm.
The researchers selected mango trees from 6 year, 18 year, and 30 year age groups and grafted on seedling rootstock sourced from a single mother plant. All experimental trees were planted with 2.5m x 2.5m spacing.
160 fruits were selected from 10 trees of each age group and data was collected for analysis of functional and nutritional characteristics.
Variables
Tree age - This categorical variable indicates the age of the mango tree. It has the value of 6 year, 18 year, or 30 year.
Firmness (N) - This numeric variable was measured with a texture analyzer using a compression test and is measured in Newtons.
Total Sugar (%) - This numeric variable was measured by taking a sample of juice and using methylene blue indicator until rick red color appeared. Measured as percentage.
Ca content (mg/kg) - This numeric variable was measured with Microwave Plasma-Atomic Emission Spectroscopy and represents the concentration of calcium in the fruit.
Mg content (mg/kg) - This numeric variable was measured with Microwave Plasma-Atomic Emission Spectroscopy and represents the amount of magnesium in the fruit.
K content (mg/kg) - This numeric variable was measured with Microwave Plasma-Atomic Emission Spectroscopy and represents the concentration of potassium in the fruit.
Activity
Get to know the data
What does the distribution of Firmness look like when plotted?
What does the distribution of Total Sugar look like when plotted?
Do any variables for mineral content (Ca, K, Mg) appear correlated?
Key Questions
1.Does tree age seem to affect Total Sugar?
Create and paste a graph below as evidence for your answer.
2. Does tree age seem to affect Firmness of a mango at harvest?
Create and paste a graph below as evidence for your answer.
3. How does mineral content in the fruit change with the age of a mango tree?
4. Low firmness makes mangos difficult to transport long distances for sale. Based on these data, what recommendations would you make for orchard management if long distance transport of the fruit crop is desired?
Statistics Extension
5. After plotting firmness on Y and tree age on X, run a statistical test to further evaluate the recommendations you made in question #7.
6. Which statistical test did you run and why?
7. Explain how the results of the test support or do not support the recommendation that you made in question #7
