Fruit & veg Flashcards

1
Q

Sunshine hours

A

time during which the direct solar radiation exceeds 120 W/m²

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2
Q

Most sunshine hours at

A

the equator and in the tropics

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3
Q

conversion efficiency from sunlight to food

A
Total solar energy  (-60% non absorbed wavelength)
(- 8% reflection- transmittion)
(- 8% heat dissipation)
(-19% metabolism)
> 5% carbohydrate
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4
Q

Efficiency of food production from solar energy to people

A

0.42% of solar energy is converted into winter wheat grain.

Conversion of grain into energy stores within the body of animals or humans = 10% efficiency.

10x more grain is required if people obtain their energy by consuming meat.

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5
Q

Daily per capita food availability

A

Global food production has been adequate every year since 1974 to meet minimal calorie requirements for everyone on earth (FAO).

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6
Q

Protein in the diet

% from what source

A

55% from grain staples
20% from animal products
13% from legumes

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7
Q

Adult daily protein intake should be

A

at least 50g/day

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8
Q

Legumes and grains provide which 4 proteins

A

= Ile L = Lys L
= Met G =Try G

Isoleucine Lysine
Methionine tryptophan

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9
Q

World food programmes (WFP) disaster food basket

A
400g of cereal flour/rice/bulgur
60gof pulses
25 g of oil (vit. A fortified)
50 g of fortified blended foods (Corn Soya Blend)
15g of sugar
15g of iodized salt
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10
Q

Nutritional value of WFP disaster food basket

A

Energy 2,100 Kcal
Protein 58 g
Fat 43g

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11
Q

Nutritional value of Peanut paste

A

Energy 545Kcal
Protein 13.6g
Fat 35.7g

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12
Q

Increases in world meat production

A

Rising incomes have increased meat consumption.

Chicken consumption is increasing in the US as people swap from eating red to white meat.

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13
Q

Strategies for reproduction

A

R strategy & k strategy

[Bennett et al., 2012]

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14
Q

R strategy selected

A
  • Mature rapidly
  • Short lived: Most die before they reproduce
  • Many offspring: Tend to overproduce
  • Most pest species
  • Population not regulated by density: boom and bust figures
  • Opportunistic: invade new areas
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15
Q

K strategy selected

A
  • Mature slowly
  • Long lived: Low juvenile mortality rate
  • Few offspring at a time
  • Most endangered species
  • Population stabilises near carrying capacity
  • Maintain numbers in stable ecosystems
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16
Q

Abiotic stress

A

Non-living =
oxygen Soil quality Temperature
Water status Mineral nutritions
Toxic minerals & allelochemicals Gravity
Humidity C2H4 (ethylene) Wind
Photoperiod Photosynthetic light
Photomorphogenic light

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17
Q

biotic stress

A

life and living organisms =
Herbivores Pathogens
Soil microorganisms Parasites

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18
Q

How short day rice variety response to light hour

A

Flowers if short daylight and long night without flash of light

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19
Q

How long day plant response to light hour

A

Flowers if long period of daylight or short day light with flash of light at night

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20
Q

Yield loss may due to

A

pests and unfavourable abiotic conditions

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21
Q

Plant defences against herbivores

A

= Chemical (secondary metabolites)
= Physiological
= Morphological

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22
Q

Example of chemical defence

A
  • Nitrogen compounds
  • Phenoloics
  • Polyacetylenes
  • Proteins
  • Terpenes
  • Other
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23
Q

Example of morphological defence

A
  • Bark and cell wall thickening
  • Spines and hairs
  • Waxy silica covered surfaces
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24
Q

Example of physiological defence

A
  • Compensate for yield loss

- Rapid repair of injured tissue

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25
Q

Pest outbreaks occur with changes in the environment

A
  • Physical environment becomes more favourable for pest reproduction, survival and growth.
  • Food plants become more abundant/ nutritious for pests
  • Natural enemies of the pest become less common
  • Competing species become less common
  • Environmental induces physiological, reproductive or genetic changes in the pest to make it better adapted to the environment/ crop
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26
Q

Locusts turn from green to black when

A

their serotonin levels rise

27
Q

Crops yields are poor in the tropics because

A

Crop productivity is highly vulnerable to variations in climate

For rice in the hot temperature, after a single hot day, only the brown grains contain rice seed that will be harvested

depends on the rice cultivar diversity for response to high temperature

28
Q

rice cultivar diversity

A

Different spikelet fertility (%) of rice genotypes to high temperature at anthesis.
[S is susceptible, T is tolerant to high temp]

29
Q

Distribution of arable land and fresh water

A

arable land = Oceania > US/ Canada > EU > Latin America > Africa> Asia

fresh water = Oceania > Latin America > US/ Canada > EU > Africa > Asia

Big distrubution difference in latin , US & EU

30
Q

% of world land is used to grow crops

A

11 %

31
Q

Grain yields respond differently to rainfall, so farmers in semiarid regions

A

often plant 2 crops:

  • One that will yield some food if the rains fail to come.
  • One that will yield abundantly if they do come
32
Q

Plant lose water through

A

evaporation, from their surfaces and leaves the plant by diffusion through the stomata.

33
Q

Which crops photosynthesis C4 / C3

A

C4 = Sorghum/ Corn

C3= Bread Wheat/ Barley/ Rice

34
Q

Biomass produced per litre of water for C4 crops

A

Sorghum 0.0036 biomass /L H2O

Corn 0.0033 biomass /L H2O

35
Q

Biomass produced per litre of water for C3 crops

A

Bread Wheat 0.0020 biomass /L H2O
Barley 0.0019 biomass /L H2O
Rice 0.0015 biomass /L H2O

36
Q

Anatomical adaptations to the problem of living in hot places for C3 plant

A

Calvin cycle in mesophyll cell

37
Q

natomical adaptations to the problem of living in hot places for C4 plant

A

CO2> malate > pyruvate in mesophyll cell

Calvin cycle in bundle sheath cell

38
Q

C4 photosynthesis

A

Ccarbon fixation begins with dissolved CO2 to bicarbonate ion, HCO3-.

Bicarbonate is combined with phosphoenolpyruvate or PEP by an enzyme called PEP carboxylase. The product of this reaction is a molecule called oxaloacetate

Depending on the species, oxaloacetate may be either converted to an amino acid called aspartate or to malate.

Converting it to malate requires reducing power in the form of nicotinamide adenine dinucleotide phosphate (NADPH); converting it to aspartate requires another amino acid.

Either way, the CO2 has now been stored in a form that can be exported for the next step

39
Q

C3 photosynthesis

A

CO2 is fixed with the aid of the enzyme, rubisco, which attaches a molecule of CO2 to ribulose 1,5-bisphosphate.

The formed six-carbon sugar is an unstable intermediate and will rapidly break apart into two molecules of 3-phosphoglycerate.

Neither these steps nor the remaining steps in the reductive pentose phosphate cycle differ from those that occur in C4 plants; the C4 plants, however, have another cycle associated onto this first one

40
Q

essential plant nutrients

A

14 = 6 macronutrients; 8 micronutrients

low N - yellow leaves
low P - plant growth is retarded.
low K - brown scorching and curling of leaf tips/ more prone to frost damage and disease

41
Q

The nitrogen cycle

A

Nitrogen in the atmosphere > Ammonification > Nitrification > Denitrification > Nitrogen in the atmosphere

[Slide 27]

42
Q

Nitrogen fixing legumes

A

Nitrogen-fixing symbionts in root nodules

Supply nitrogen to cropping systems

Reduces need for nitrogen fertiliser on the subsequent crop.

43
Q

Soybean, red clover and alfalfa can fix how much N/ ha/ yr

A

45-225 kg of N/ha/yr.

44
Q

Global Fertiliser use trend

A

Decreasing in developed countries

Increasing in developing countries

Global use of nitrogen fertilisers increased by 33% in past 20 years

45
Q

Strategies for improving soil quality

A
  • Hydroponic cultivation
  • Pests and pest management
  • Diversify cropping systems by crop rotation
  • Keep the ground covered - reduce wind and water erosion and improve water availability
  • Prevent soil compaction
  • Avoid excessive tillage- reduce loss of organic matter and protects the soil surface with plant residue.
  • Enhance organic matter
46
Q

Hydroponic cultivation

A
  • Allows controlled nutrient application
  • High energy cost
  • No problem with water availability to the crop
  • Can cause problems with diseases that like high humidity
  • Rapid growth
47
Q

Pests and pest management

A
  • Herbicides – usage and problems
  • Pests
  • Problems with pesticides
  • Integrated pest management
48
Q

Disease triangle

A
  • Favorable environment
  • Pathogen
  • Susceptible host
49
Q

worldwide crop losses in farming from insect and pest mites (1988- 1990, comparing to 1965)

A
  • Potatoes has great increase in crop loss

- Rice has reduce its crop loss

50
Q

Strategies used in integrated pest management

A
= Biological control
= Cultural Control  
= Mechanical and control
= Reproductive and genetic control 
= Chemical control
51
Q

Pest Biological control

A

The use of natural enemies to control pest population

52
Q

Pest Cultural Control

A

Modification of crop management practices or the crop itself

53
Q

Pest Mechanical and control

A

The control of pests using physical means i.e traps, barriers heating etc.

54
Q

Pest Reproductive and genetic control

A

To reduce the reproductive success of pests

55
Q

Pest Chemical control

A

Pesticides; Behaviour disrupting pheromones

56
Q

Ex of biological control agents

A

Parasitic wasps

57
Q

Parasitic wasps as biological control agents

A

Adults free living feed on nectar, F & M mate
> Eggs inserted into host by ovipositor of female
> Parasite larvae develop within body of host
> Mature larvae emerge from body of now dead host and spin cocoons to pupate
> Adults emerge from cocoons at suitable time for new generation of host
> Adults free living on nectar

58
Q

Organic farming practice

A

Shallow ploughing, manuring and crop rotations including nitrogen fixing plants are used to maintain soil fertility without the use of soluble fertilizers.

Herbicides are not allowed and only a few pesticides can be used under strict conditions.

As far as possible livestock are land-based and supported from the farm’s own resources with a minimum of bought in feeds.

Required to maintain habitats for wildlife, such as hedges and field margins

59
Q

Plant breeding

A

Genes are located on chromosomes

In a diploid genome there are two alleles of each gene

Some traits are controlled by singles genes

Many traits are controlled by more than one gene

Some genes are part of ‘gene families’

60
Q

Traits to breed for

A
Height
Stem thickness
Root depth
Flowering time
Flavour
Increased nutrition
Drought tolerance
Less requirement for NPK
61
Q

Gregor Mendel (1822-84)

A

Observation of characters including round vs wrinkled peas, white vs purple flowers

when two pure breeding lines were artificially crossed the progeny (F1) are all identical but similar to one of the parents.

But when the F1 plants were allowed to self the progeny resembled one or other of the original parents.

62
Q

Mendel discovered

A

Traits are controlled by heritable factors

Factors are passed from parent to offspring via reproductive cells

Each plant contains PAIRS of factors (gene alleles ) (excepting reproductive cells)

Each reproductive cell receives ONLY ONE of the factors of a pair

Probability as to which one is received is random

Probability as to which factor it pairs with in new plant is random

Factors show dominance (recessive) over one another

Two, or more, pairs assort independently

Crosses help determine the genotype of the parental lines.

63
Q

Dihybrid crosses

A

Where smooth (S) is dominant to wrinkled (s) and yellow (Y) is dominant to green (y). Such that the heterozygotes (SsYy) would be smooth and yellow.