W2 - Lecture 2A - Optimising Grain Yield And Crop Physiology

Question 1

what are the 4 yields in cereal crops

Answer 1

• Economic Yield
• Biological Yield
• Potential Yield
• Actual Yield

Question 2

what is economic yield

Answer 2

grain yield

Question 3

what is biological yield

Answer 3

total biomass yield

Question 4

what is potential yield

Answer 4

perfect crop/weather

Question 5

what is actual yield

Answer 5

~ 60-65 % of potential

Question 6

what is definition of Harvest Index

Answer 6

gives an indication of the relative size of the grain yield (economic) to the rest of the plant (biological)

Question 7

what is the equation of Harvest Index

Answer 7

Harvest Index = Economic Yield /(divided by) Biological Yield

Question 8

Yield Components of Old and New
Cultivars
table
slide 6 & 12

Question 9

Yield Components for two modern Winter Wheat varieties - Madrigal and Savannah in a very high yield trial at UCD Lyons farm

Variety - Madrigal :

Ears/m2
Grains/ ear
1000 Grain Wt
Yield(t/ha)

Answer 9

Variety - Madrigal
Ears/m2 - 460
Grains/ ear: 54
1000 Grain Wt: 62
Yield(t/ha): 15.4

Question 10

Yield Components for two modern Winter Wheat varieties - Madrigal and Savannah in a very high yield trial at UCD Lyons farm

Variety - Savannah
Ears/m2
Grains/ ear
1000 Grain Wt
Yield(t/ha)

Answer 10

Variety - Savannah
Ears/m2: 500
Grains/ ear: 52
1000 Grain Wt: 60
Yield(t/ha): 15.6

Question 11

what has happened UK wheat yields 1885-2010

Answer 11

increased

Question 12

UCD Spring Oats Trial 2021
Heritage Lines v Modern
Cultivars

Lodging Issues(2)

Answer 12

• Lodging levels were extremely
  high on many of the heritage
  lines.
• All were salvageable but
  caused a lot of mechanical
  problems. 4 breakdowns due to
  lodging, all attributable to older
  genetic material.

Question 13

Name the 3 crop improvements in cereal crops

Answer 13

1. technical progress
2. genetics
3. mechanisation

Question 14

Technical progress - 5

Answer 14

Varieties
Fertilisers
Insecticides
Herbicides
Fungicides & PGRs

Question 15

Genetics

Answer 15

Genetic Improvement – crop breeding

Underpinned by the Recommended List variety testing program

Question 16

Mechanisation -3

Answer 16

Cultivations
Spraying
Harvesting

Question 17

Role of harvest index improvement in
yield improvement

Answer 17

Harvest index rises as yield ()\t/ha rises

eg
Har. Index Yield(t/ha)
36, 5.22
42 5.86
51 7.10
55 8.25

Question 18

Apical development

Answer 18

• floral (spikelet) initiation phase

Question 19

def: biological yield

Answer 19

total crop yield of wanted and
unusable components

Question 20

what is the Leaf Area Index (LAI) ratio

Answer 20

ratio of leaf area to ground area,

Question 21

def:
Net Assimilation Rate (NAR)

Answer 21

dry matter production / leaf area

Question 22

what does LAI stand for

Answer 22

Leaf Area Index

Question 23

what does NAR stand for

Answer 23

Net Assimilation Rate

Question 24

crop growth rate equation

Answer 24

LAI x NAR

Question 25

what is the Leaf Area Index

Answer 25

This is the crop canopy

Question 26

what is the optimum LAI FOR CEREALS

Answer 26

optimum for cereals is 4-5

Question 27

Potential Yield for GS30(end of tillering)

Answer 27

tillers - 8 per plant
spikelets - 19 per plant
florets - 5 per spikelet

Question 28

what is GS30

Answer 28

END OF TILLERING

Question 29

Potential Yield at GS75 (mid-grainfilling)

Answer 29

tillers - 2 per plant
spikelets - 15 per plant
florets - 2.5 per spikelet

Question 30

what is GS 75

Answer 30

mid-grainfilling

Question 31

Breakdown of Grain Site Losses

Answer 31

diagram slide 22