Plant Biotechnology and Breeding

Why are some plants breeded?

increased yield of protein and starch, for vegetative structures, for non-food products, develop new cultivars

What qualities does a new cultivar need to have?

distinctness, uniformity, and stability

What are crops being VCU trialed in Ireland?

barley, wheat, oats, grasses, clovers, forage maize, winter oilseed rape, potatoes

environmental costs of intensive farming

increased ghg, decline in soil productivity, overgrazing, hazards to life, detrimental effects on food quality, destruction of wildlife, pollution of surface waters

conventional agriculture

ultimate goal is the safe, efficient provision of foods in abundance at a low price

organic agriculture

more environmentally friendly and more sustainable than conventional high yield agriculture

integrated farm management

combines the best of traditional farming with responsible use of modern technology

first generation energy crops

sugars and oils from standard arable crops

second generation energy crops

any form of biomass

What are dedicated energy crops and trees in Ireland?

perennial rhizomatous grasses and short rotation coppice willows

What are the two major sources of genes for breeding?

crop wild relatives and landraces

crop wild relative

relative of the crop but growing wild and not domesticated; genes can be used via conventional breeding as they are closely related to the crop

landrace

a variety of crop and has been domesticated; often have high diversity and used to make cultivars

How is chromosome number and ploidy measured?

chromosome counts and flow cytometry

aneuploids

gain or loss of one or a few chromosomes

Why are homozygous lines required in cultivars?

for uniformity

double haploids

generates homozygosity without inbreeding over many generations

autopolyploids

have more than 2 genomes from the same species

allopolyploids

combine genomes from more than one ancestral species

describe the floral dip method

plants grown to just flowering, inflorescences are dipped briefly in a suspension of agrobacterium, plant grown until mature and progeny seeds harvested, seeds germinated on selective medium

Why do scientists make transgenic plants?

GM crops, plant molecular pharming, investigation of plant genes

What is algal agriculture?

cultivating in a controlled or semi-controlled environment for commercial use; combines traditional agriculture with aquaculture

What are the main macro-crops of algae?

nori, sweet kombu, wakame, cottonii, spinosum, ogo

Grasses for bioenergy or building materials

Miscanthus, Panicum, Phalaris, Bambusoids, Arundo

What are the grass subfamilies?

BEP, PACCMAS, Early Diverging lineages

examples of c3 pooids and ehrhartoids

wheat, rye, rice

examples of c4 panicoids

maize, miscanthus, sugarcane

general structure/parts of grass

roots, culm, sheath, ligule, blade, inflorescence, spikelets/florets, nodes

What type of roots does grass typically have?

adventitious often with rhizomes

grass inflorescence types

panicle, racemes, spike

spikelet

may contain many florets

rachilla

disarticulates at maturity

lodicules

highly reduced petals

lemma and palea

protective bracts

typical grass fruit

a caryopsis, single seeded fruit pericap fused to see coat

What is research and development?

exploration and manipulation of biological systems and living organisms to create novel solutions

endophyte

any organisms able to live within the plant (virus, archaea, bacteria, fungus)

How are endophytes horizontally transmitted?

wounds, stomata, lenticels, nodules, cuticleH

How are endophytes vertically transmitted?

seed

What are the approaches to working with microbiomes?

environmental microbiome manipulation and crop inoculants

general suppressiveness of soils

collective microbial community

specific suppressiveness

due to the concerted activities of specific groups of microorganisms

syncoms

engineering the soil microbiome

What are the sources of variation for breeding?

new germplasm, new crosses, mutagenesis, genetic engineering

How to choose which breeding method to use?

It depends whether the traits are single gene or quantitative and the mode of plant reproduction

selection for trait controlled by recessive alleles

only requires one round of selection

selection for trait controlled by dominant alleles

requires several rounds of selection before it’s fixed in a population

quantitative trait loci (QTL)

stretches of DNA linked to or containing the genes determining a quantitative trait (polygenic); can be mapped to chromosomes

cleistogamy

flower fails to open; easily selfed; sometimes occurs under stress; has the potential to control GM cross pollination

What are some self pollinated crop examples?

barley, wheat, oat, rice, clover, lettuce, peanut, tomato, cotton

single seed descent

often used to quickly obtain uniformity of new hybrid seed for trialing

Why is male sterility often used in breeding?

can ensure cross pollination, control direction of pollination, plants may lack male organs

cytoplastic male sterility (CMS)

transmitted through female parent in mitochondria; abnormal protein causing sterility is expressed in mitochondria in all cells of a plant but in pollen development it is toxic

crossing and selection

relies on allele segregation/assortment to generate genotypic variation

pure line selection

used to develop a new variety by selection of single best progeny in a pop; self pollinated descendant of a self pollinated plant; assumes desirable types already exist in population