vegetable crops lectures 8-11

what is sustainability?

the idea of meeting the needs of the present without compromising the ability of future generations to meet their own needs

what are the pillars of sustainability?

environment, economy, equity

what is included in the ‘environment’ pillar of sustainability?

pollution, biodiversity, minimising waste, climate change

what is included in the ‘economy’ pillar of sustainability?

business development, job creation, productivity, trade

what is included in the ‘equity’ pillar of sustainability?

equity, health, culture, history, and livability

what are some effects of conventional food production on the environment?

• decline in soil productivity

• erosion of topsoil

• increased soil compaction

• loss of SOM

• loss of biological activity

• salinisation of soil and water on irrigated farms

what is monocropping?

continuously growing the same crop for multiple seasons

what are some characteristics of monocropping?

mechanisation, massive monocultures, chemicals

what are the disadvantages of monocropping?

• soil erosion

• reliance on chemical inputs

• crop easily decimated by pests/disease

what are the issues with seasonal tilling?

erosion, compaction, formation of plough pans

how are plough pans formed?

consistent ploughing of top 20cm of soil leads to an accumulation of minerals, which harden (Fe)

monocropping leads to soil fatigue, which means

the soil is unable to support plant growth

what agricultural substances pollute the environment?

pesticide run off, fertilisers, microplastics

how do microplastics pollute farms?

microplastics are small enough to be absorbed and pass into roots and leaves

what are the effects of eutrophication?

a thick algae layer doesn’t allow light penetration, which prevents plant growth and respiration, which depletes water O2 and kills off animals

how does rice production harm the environment?

wetting creates anaerobic conditions and producing methane, drying releases that methane into the atmosphere, resetting continues the cycle

what are some economical issues in agriculture?

small-scale independent farms replaced by large mono-cultural operations, limited market competition through supply chains, government subsidies end up with large companies

what are some social issues in farming?

income disparities caused by limited market competition and economic pressures, inequality and food security, more vulnerable to health issues

what does a sustainable food system look like?

encouragement of local production and distribution systems, food made available, accessible, and affordable, production of food is humane and just

what is a sustainability index?

an instrument used to measure the sustainability of a business across environmental and social factors

what is needed for more sustainable vegetable production?

• improve soil fertility

• increase use of biologicals

• replace chemical fertilisers with organic alternatives

• increase biodiversity

• support employees through education and policy

how is more sustainable vegetable production achieved?

• crop rotations, cover crops, reduced tillage

• IPM, bio-based products, cultural practices

• habitat creation and pesticide reduction

• support local suppliers, new tech, entry-level wages

what is used to manage and track business sustainability levels?

key performance indicators (KPI)

what are some environmental KPIs?

energy and resource consumption, emissions of pollutants into the air, nutrient pollutants in groundwater

what are some economical KPIs?

profitability, standard vs minimum wages, spending on local suppliers

what are some social KPIs?

labour practices, equality-diversity-inclusion (EDI), community engagement

what is organic vegetable production?

method of farming that uses natural processes and materials to grow vegetables without synthetic chemicals or genetically modified organisms

according to the USDA, what are the requirements for a farm to be organic?

• vegetables grown in soil not treated with prohibited substances for at least 3 years

• only organic or untreated seeds

• no use of GMOs

• cultural, mechanical, or biological pest and disease management

• submission of an Organic Systems Plan

• certified by National Organic Program

in the EU, what are the regulations for organic farming?

• GMOs prohibited

• use of onsite resources for natural fertilisers

• limited use of artificial fertilisers, pesticides, herbicides

• promote cultural, mechanical, biological pest and disease control

• minimum 95% organic ingredients in processed foods

what are GMOs?

organisms whose genetic material has been artificially modified in order to create a desired trait

why aren’t GMOs considered organic?

• direct genetic manipulation contradicts reliance on natural biological systems

• concerns about potential long-term effects on ecosystems, biodiversity, and human health

• organic farming guides by consumer expectations for minimal processing

what is CRISPR?

clustered regularly interspaced short palindromic repeats

originally a defensive immune system bacteria, now used in gene editing to add or remove genes in plants

how does CRISPR work?

• virus attempts to infect and highjack bacterial processes

• viral RNA recognised, Cas enzymes cut out foreign RNA

• foreign RNA integrated into host CRISPR array for immunological memory

• Cas9 proteins can detect foreign nucleotides and cleave

how do we use CRISPR?

generate RNA versions of target to be used as ‘guides’ for Cas9 enzyme

what are botanical extracts used for?

natural and organic pesticides that come from plants and minerals contain compounds to manage pests and diseases

what are the most important USDA regulations?

traceability and certification

what are the main goals of plant breeding?

to develop plant varieties that meet specific needs

what needs can plants be bred to meet?

sterility, pest and disease resistance, environmental tolerances, nutrition

is pedigree breeding through self pollination considered GMO?

no :)

how long can pedigree breeding take?

6–7 years

how does pedigree breeding work?

• parents either similar desirable traits crossed to develop a segregating F1 pop.

• record kept of each parent-progeny details

• next gen is selfed, then next and continued until traits and characteristics become apparent

what is a potential issue of pedigree breeding?

inbreeding depression

is another culture considered GMO?

no :)

how does anther culture work?

uses the totipotence of plant cells to create haploid plants, in which recessive traits can be identified (homozygous)

immature pollen from anther is cultured on nutrient medium

is transgenic modification GM?

yes

what is transgenic modification?

introduces a new trait to the plant which does not naturally occur in the species (e.g. golden rice with beta carotene)

is cisgenic modification GM?

depends on how the gene was targeted and moved

what is cisgenic modification?

indroduction of new traits from one plant to another from the same species (e.g. cabbage to cabbage)

how does CRISPR knock out genes?

suppresses expression

is CRISPR considered GM?

yes :(

how were most transgenic plants developed?

agrobacterium-mediated approaches

agrobacterium: pathogenic bacterium that infects wounded cells and causes crown galls

how does agrobacterium affects genes?

• cuts TDNA from plasmid

• injects into plant cell

• transports to plant cell nucleus

• TDNA injected into plant cell DNA to aid agrobacterium survival and reproduction

what is the main reason for potato’s success as a crop?

easy to grow, can be grown in many different climates, excellent source of nutrients, carbs, proteins, antioxidants

what family do potatoes belong to?

Solanaceae

why are potatoes grown as annuals?

biennial = year one focuses on development of storage organs and energy, which is what we want to harvest

how hardy are potatoes?

half-hardy, quite frost sensitive

how are potatoes generally propagated?

vegetatively through tubers

when do potato flowers bloom?

60–70 days after planting

how are potatoes primarily pollinated?

bumblebees, self pollination

why don’t we eat potato fruits?

HIGHLY TOXIC

where do we use sexual reproduction in potatoes?

crop improvement

what do potato leaves look like?

pinnately compound, alternate, 7–9 ovate leaflets with one terminal leaf, serrated or entire

why are potato leaves important?

photosynthesis = generation of energy = bigger tubers

what can lodging cause in potatoes?

development of toxic substances when tubers are exposed to the sun

what is the lifespan of a potato plant?

80–150 from planting to maturity

what does stem density affect in potatoes?

stem height (higher density = taller stems = lower axillary branching)

what is ‘burning’ when referring to potatoes?

destroying the stem for easier harvest

what kind of root architecture do potato’s have?

initially fibrous and shallow

what are stolons?

modified underground stems

what are tubers?

enlarged portions of stolons

what triggers stolen formation?

colder soil temps, shorter photoperiods, growth hormones

who is the biggest global producer of potatoes?

china

what are the four potato growing zones in china?

northern single crop zone, central double crop zone, southwestern mixed crop zone, winter crop zone

how many unique chromosomes do potatoes have?

4 (tetraploidy)

why is genetic expression difficult in potatoes?

relies on all four chromosomes having certain gene

what is the main disease in potatoes?

potato blight (phytophthora infestans)

when did the potato famine happen?

1840s

how can growers fight potato blight?

regular application (up to 15) of fungicides at high rates and short intervals throughout the growing season

50% of main crop potatoes grown in ireland are

roosters

when is true seed used in potato growing?

when disease pressures are too high for seed tubers

how is vegetative reproduction done in potatoes?

seed pieces cut and allowed to suberize for 7–10 days

what is suberisation?

process that allows for a corky protective layer to form around seed piece, which prevents decay and decreases pathogen and pest penetration

what is true seed (potatoes)?

cross-pollination is manipulated for crop improvement in quality and insect/disease resistance

why can potato’s cause problems in breeding programs?

many cultivars are pollen sterile

when are early potatoes planted and harvested?

march, june-july

when are second-early potatoes planted and harvested?

april, july-august

when are main crop potatoes planted and harvested?

april-may, september-october

what is tissue culture used for in potato production?

perpetuate disease-free seed stock, which can be stored in vitro until needed

what is the ideal soil for potatoes?

well drained, well aerated for root aeration and tuber development, slightly acidic 5.5-7.0

why is conservation tillage unsuitable for potatoes?

big clods, stones, impediments can disrupt even tuber growth

what is potato scab?

soil-borne pathogen from dry conditions (skin peels, bacteria enters)

how is potato scab managed?

soil moisture and pH

what is the ideal seedbed depth for potatoes?

at least 12 inches for good drainage and soil aeration

why is mounding done for potatoes?

strong sunlight triggers chlorophyll + solanine production in tubers

when does sprouting occur in potatoes?

2–4 weeks after planting

how much NPK do potatoes need?

good amounts for good yield, fertiliser application affects yield, tuber size and quality

what is a sign of N deficiency in potatoes?

yellowing in leaves

how can excess N affect potatoes?

delay in tuber development, foliage susceptible to disease and blight

what are signs of P deficiency in potatoes?

bluish tint, browning at leaf tips and edges

what can phosphorus encourage in potatoes?

early rooting, later maturity, harder skins, may reduce tuber blight