Agricultural Science: Potatoes and Barley (Strand 3)

Comprehensive practice questions covering Irish potato production, growth cycles, cultivation methods, disease management, and genomics as detailed in the lecture notes.

How many hectares of potatoes are grown on average in Ireland each year?

$9,000$ hectares.

What is the average annual potato consumption per person in Ireland today?

Around $85\,kg$ per person (decreased from $140\,kg$ in the 1990s).

Which five counties in Ireland account for $80\%$ of potato production?

Meath, Dublin, Donegal, Cork, and Louth.

What is the Latin name and family of the potato?

Latin Name: $Solanum\,tuberosum$; Family: Solanaceae.

Structurally, what part of the plant is the potato tuber?

A modified stem used for food storage in the form of starch.

List the five stages of the potato growth cycle.

1. Sprout development, 2. Vegetative growth, 3. Tuber initiation, 4. Tuber bulking, 5. Maturation.

During which stage of the growth cycle does the plant flower above ground?

Tuber initiation.

What is the approximate maturation time for First Early potatoes?

About $3.5$ months (approximately $100$ days).

What variety accounts for $70\%$ of the Irish main crop, and what is its typical texture?

Rooster; it is generally a floury potato with a high dry matter (DM) content.

Why is Donegal specifically chosen for the growing of certified seed potatoes?

It is isolated from main ware potato regions and has low numbers of aphids due to a cool climate with high winds, resulting in fewer viruses.

What are the three main viral diseases tested for in the production of seed potatoes?

Leaf mosaic virus, Leaf roll, and Virus Yellow (Virus Y).

What are the rotation requirements for ware potatoes versus seed potatoes?

Ware potatoes should not be grown in the same place more than $1$ year out of $4$; seed potatoes should not be grown more than $1$ year out of $5$.

What is the optimum soil pH for potato growth?

A pH between $5.5$ and $6.0$.

What depth should potatoes be ploughed to in the Autumn?

$22\,cm$.

What is 'Chitting' and why is it beneficial?

The process of triggering the seed potato to produce sprouts before planting; it allows for an earlier harvest and increases yield and quality.

What are three functions of the 'Earthing up' process?

1. Reduces weeds; 2. Prevents zoo spores falling from leaves onto tubers; 3. Prevents tubers from going green when exposed to light.

What are the negative effects of applying excess Nitrogen ($N$) to a potato crop?

Increased tuber size due to water (lowering cooking quality), making the crop more prone to disease (especially blight), and delayed development/harvest.

What is the primary role of Potassium ($K$) in potato nutrition?

It is necessary to prevent bruising and to increase tuber size.

What fungus causes Potato Blight and in what conditions does it spread?

$Phytophthera\,infestans$; it spreads in temperatures above $10^\circ\text{C}$ with high humidity.

What causes Common Scab, and what cultural method can prevent it?

The bacteria $Streptomyces\,scabies$; it can be prevented by irrigating dry or sandy soils for the first $6$ weeks of tuber growth.

Name two notifiable bacterial diseases of potatoes not currently present in Ireland.

Brown Rot ($Ralstonia\,solanacearum$) and Ring Rot.

Which pest causes damage by boring into tubers and is a particular problem when potatoes follow grass in rotation?

Wireworms (Click Beetle larvae).

What toxin is produced when potato tubers are exposed to light and turn green?

Solanine.

What is 'desiccating' or 'burning off' in the context of potato harvesting?

Killing off the haulms (foliage) with herbicide before harvesting to make harvesting easier and prevent blight transmission.

What are the typical yields for Early versus Maincrop potatoes?

First and Second Earlies: $7\text{--}10$ tonnes per hectare; Maincrop: $30\text{--}40$ tonnes per hectare.

At what temperature should a potato storage unit be maintained to prevent sprouting?

$4\text{--}6^\circ\text{C}$.

How does genomics contribute to the sustainability of potato production?

By selecting for disease resistance (reducing pesticide reliance), improving quality (reducing wastage), and lowering financial costs related to chemicals and labour.