Sjaak van Heusden

History and Impact of Plant Breeding

Sjaak van Heusden

Domestication

▪ Humans have domesticated plants and animals for the permanent use of their most favourable characteristics.

▪ Domestication (Latin domus, house) is the process in which humans changed animals and plants (through selection and breeding) in a way that they are more and more useful for humanity (food, ornamentals, medicine, clothes etc.)

7

Breeding/Domestication

Balter, Science 2007 12

Plant Breeding

▪ History

▪Was it successful?

▪ Is it still needed?

▪What are the main goals?

▪ How do they Plant Breeders operate nowadays

● Can they do it alone (without other scientists)?

History of Plant Breeding

12,000 years ago

First accidental discovery of genetic variation followed by

domestication

- 10,000-3,000 years ago

Primitive agriculture, saving seeds of best material

- 1870 - 1910

Mendel and rediscovering laws of Mendel

- 1930

More and more science involved

History of Plant Breeding

1960

Involvement Celbiology (Embryo rescue)

1985

Plant biotechnology met Genetic Modification and “Marker

Assisted Selection”

2000

Sequencing whole plant genomes, new possibilities for

breeding ( easier to identify essential genes)

Methods like “Genomic Selection”

2010

- More and more biotechnology, site directed mutagenesis

(CRISPR-cas9)

Why is breeding important for the

Netherlands

▪ Over 350 companies:

● Plantbreeding/selection

● Production cuttings, seeds, young plants

● Tissue culture

● Export of plant material (8.5 x 109 Euro)

● NL world biggest exporter of seeds and seedlings

LandbouwBloemenGroentezadenJonge planten

Plantum 2012

Plant Breeding - Definitions

▪ The art and science of changing (the genetics of) plants for the benefit of mankind

● Improvement in the quantity or quality of the economic product of plants

▪ Plant Breeding is evolution directed by the will of man (Vavilov 1887 -1943, gene banks, supported Mendel and de Vries, not Lysenko, inheritance gained characteristics )

Objectives Plant Breeding

▪Development of crop cultivars with improved yield

(both quantity as quality) and stability of

performance and possessing resistance to

abiotic (thermo tolerant, drought, salinity, frost,

cold etc.) & biotic stress (diseases and insect

pests) with value added traits (also biobased

applications)

Plant Breeding

▪ Use of biodiversity

▪ New combinations of genetic material

● Intraspecific and interspecific hybridisation

▪ Mutation breeding - Ploidy manipulation - More and

more science driven

Mutation Breeding

▪ Limitations mutation breeding

● It is random and cannot be directed

● Time, place of occurrence and frequencies are

unpredictable

● Most mutations are of no practical value

● Desired single gene mutations are often accompanied by

additional chromosomal damage

Overall

▪ Mutation breeding has become an adapted method on limited scale and complementary to other methods

▪ Today there are three groups of breeders:

● Mutation breeding is useless, we can accomplish the same thing with conventional methods,

● Mutation breeding will produce a breakthrough given enough effort,

● Mutation breeding is a tool, useful to meet specific objectives

● New methods can replace mutation breeding

All important cultivatedornamental plants are interspecific (polyploid)hybrids

Breeding in ornamentals

▪ Quality traits

● Mutation Breeding

● Chromosome and ploidy manipulation

● Germplasm exploration

● Overcoming interspecific hybridization barriers

● Embryo rescue

Polyploidy in Breeding

▪ Polyploids

● increased cell size, vigorous growth especially flower parts

● pollen inviability and reduced fertility

● combination of characters of parental species

Overcoming interspecific hybridization

barriers

Inhibition of pollen tubegrowth in the style

Ovary with ovules

Pollination

Style manipulations:cut-style, grafted style

Cut style pollination

Grafted style pollination

When became Breeding really successful?

▪ 20th century

● Involvement of science in breeding

● Selection also driven by genetics, phytopathology, entomology, biochemistry, statistics, agronomy

● Technological developments: DNA level, molecular markers, sequencing, computer science

The value of Plant Breeding

Corn Wheat Rice* Cotton

Year litre/a litre/a kg/a kg/a

1910 1000 500 42 79

1940 1050 556 57 114

1970 2635 1128 117 198

2010 5896 1600 176 287

~ 6 ~ 3 ~ 4 ~ 3.5

• More rounds of

cultivation/year

What contributed to yield increase

▪ Climate change

▪ Fertilizer

▪ Herbicides

▪ Better equipment/ favourable culture conditions

▪ Improved use of Genetic Potential- Plant Breeding

● Depending on conditions, 20-90% of the increase

Breeding objectives - how to set these objectives?

▪ High yield; nice regular shape and size of product

▪ Resistance to lodging – bending or breaking over of plants before harvest

▪Winter hardiness

▪ Heat and drought tolerance

▪ Marketing division of company: questions growers, traders and processors and consumers (= chain) for their demands

▪ Product Quality

▪ New growing conditions

Changing greenhouse conditions

▪What do the new developments mean for the plants in the greenhouse ?

energy use per kg of product

0

20

40

60

80

100

1980 1990 2000 2010

Realization until 2002 Commitment until 2010

▪ In a greenhouse there is an interaction with humidity

moisture

Heath (energy)

32% of energy gets lost

After period with energy surplus in summer

warm aquifer filled, cold aquifer empty

18 oC 5 oC

Heath exchanger

After winter:

warm aquifer empty, cold aquifer filled

18 oC 5 oC

Heathpump

Heath exchanger

Closed greenhouse

Breeding objectives - how to set these objectives?

▪ Pathogen/pest pressure

● Which pathogen/pest is serious enough to warrant investments in introduction of resistance?

▪ Legislation

● If pesticides are outlawed, more priority should be given to resistance breeding

Breeding objectives

• Complex

genetics

• Many genes

involved with

minor effects

• Whole

genomic

selection

Breeding objectives : Yield

Quality

Breeding objectives

Lambada

quality

Breeding objectives

▪ Improvement of quality traits

▪ protein & starch content (potatoes, cassava, beans, peas,..)

▪ protein composition (soy bean, wheat, rice)

▪ baking quality (bread wheat)

▪malting quality (barley)

▪ digestibility (silage maize)

▪ frying quality (potatoes)

▪ tastiness (fruits, vegetables,..)

▪ shelf life (fruits) or vase life (flowers)

▪ Etcetera, etceteraGenetics : simple → complex

Breeding objectives

▪ Yield stability, yield security

▪ Mixing cultivars with different characteristics. Why or why not ??

▪ Biotic & abiotic stress factors

▪ Healthier?

▪ One cultivar accounts for 95 percent of the global export market Cavendish)

▪ Resistant to Fusarium in the 1950s

▪ New strain

▪ Threatens all Cavenishbananas

Developments

Ecuador

India

Ghana