Chapter 14: Plant Breeding, Propogation, and Biotechnology

What percentage of the calories consumed by humans is provided by plants?

80%

What are the six species that provide most of the calorie consumption by humans?

Wheat, rice, corn, sweet potato, cassava

How many living species of flowering plants are there?

250,000

What are the eight additional plants that complete the list of major crops for human consumption?

Sugar cane, sugar beet, bean, soybean, barley, sorghum, coconut, and banana

What does the reproductive success of a domesticated plant depend on?

Human intervention

What type of process is the genetic alteration of domesticated plants?

Ongoing evolutionary process

How many years ago did people began to domesticate plants in Near East?

10,000 years ago

When did domestication in Asia and New World occur after first domesticated plants?

1,000 to 3,000 years later

What were the first crops to be domesticated?

Cereal grains

What crops were domesticated 1,000 to 2,000 years later after cereal grains?

Root crops and legumes

Which crops followed root crops and legumes to be domesticated plants?

Vegetables, then oil, fiber and fruit crops

What are the usages of plants first domesticated about 2,000 years ago?

Forage, decoration, and drugs

Where was agriculture originally believed to have originated from?

In one region in a short period of time near the Upper Euphrates River

Where are first crops said to have been domesticated now?

In several locations over a prolonged time period

What was the first altered trait during domestication?

Seed dispersal

Which plant were people more likely to gather seeds from?

Plants that retained them

Which seeds were favored by humans?

Large seed seeds that were produced in large numbers

Which type of seeds were most likely to be selected?

Seeds that germinate immediately without need for dormancy

What type of evolution is plant breeding?

Accelerated evolution guided by humans rather than nature

What do breeders replace natural selection with to modify plant genetics?

Human selection

What is the goal of plant-breeding programs in order to improve yield?

Disease resistance, pest resistance, and stress tolerance

What does genetic variation provide?

Foundation for improving plants through breeding

What is a self pollinating plant capable of?

Fertilizing itself

What does a self-pollinating plant tend to be?

Highly homologous (genes from same parent)

What are examples of plants that have undergone significant inbreeding?

Wheat, rice, oats, barley, peas, tomatoes, peppers, some fruit trees: apricots, nectarines, citrus

How are the seeds grown in a pure-line selection?

Seeds from individual plants grown in same row and most desirable is selected

How must a cross-pollinating plants be fertilized?

From other individuals

What do cross-pollinating plants tend to be?

Highly heterozygous

What are examples of cross-pollinating plants?

Corn, rye, alfalfa, clover and most fruit, nuts, and vegetables

What occurs to the plants in mass selection?

Many plants from a population is selected

What occurs to the seeds of a plant during mass selection?

Seeds from best plants chosen and propagated, for many generations

Who is known as the “Father of Green Revolution”

Norman Borlaug

What did Norman Borlaug win the Nobel Peace Price for?

Increasing the world food supply

What did Norman Boulaug develop?

New, high-yielding strains of wheat

What does outcrossing in cross-pollinated crops often result in?

Hybrid vigor (heterosis)

What does self pollination of cross-pollinating plants result in?

Inbreeding depression due to depression of deleterious recessive alleles

What do modern breeders force self-pollination in cross-pollinated species to create?

Inbred lines in which deleterious alleles eliminated

What are selected inbred lines crossed to produce?

Hybrid seed

What are hybrid seeds successful in?

Corn

What are Heirloom varieties grown as?

Open-pollinated populations

What does genetic variability allow crop production to thrive under?

Different environmental conditions

What is required for an improvement in population?

Genetic variability for trait

What is Germplasm the sum total of?

A plant’s gene

Why are current agricultural varieties not good sources of new genetic variability?

Often genetically uniform

What makes current agricultural variates vulnerable to pest outbreaks?

Homogeneity

What are gene banks established to meet?

Current and future demands of plant genetic diversity

Where are seeds or other propagules put in gene banks?

Into long-term storage

What does Protoplast fusion use across species boundaries?

Incompatible Germplasm

Where are the cells of each species grown in during protoplast fusion?

Liquid nutrient solution

What are the cell walls chemically stripped to produce during protoplast fusion?

Protoplasts

What are protoplasts of two species mixed together and stimulated with aid of?

An electric current or chemical solution to fuse with each other

How are hybrid fusions grown during protoplast fusion?

By tissue culture

Somatic hybrids

New plants that carry genes from two distantly related species