Chapter 5 Seed Selection. Self-pollination Fixed traits (homozygous) = inbred

Chapter 5Chapter 5Seed SelectionSeed Selection

Self-pollination

• Fixed traits (homozygous) = “inbred”

Self-Pollination

Non-inbred

Inbred1x

Inbred2x

Cross-pollination

• Fixed traits (homozygous) = “inbred”

Controlled crosses

Controlled crosses

Controlled crosses

Cross-Pollination& hybrid vigor

B73 B73 x Mo17 Mo17

Cross-Pollination& hybrid vigor

B73 Mo17 B73 x Mo17

Avoiding self-pollination

• Pollen sterility - genetically engineered

CytoplasmicMale Sterility

Avoiding self-pollination

• Pollen sterility - genetically engineered Cytoplasmic Male Sterility

Avoiding self-pollination• Pollen sterility - genetically

engineeredCytoplasmic Male Sterility

Avoiding self-pollination• Pollen sterility - genetically

engineeredCytoplasmic Male Sterility

Sexual incompatibility

Sexual incompatibility

• Often found in the following plant families:– Solanaceae (nightshade family)– Rosaceae (rose family)– Scrophulariaceae (snapdragon family)– Fabaceae (bean family)– Poaceae (grass family)

Sexual incompatibility

• Examples in the rosaceae include:– Apples– Cherries– Plums

Sexual incompatibility

• Pollen prevented from reaching ovule.

• Pollen either does not germinate on the stigma or the pollen tube is prevented from traveling down the transmitting cells in the style

Sexual incompatibility

Normal pollen germination

Germinationprevented

Self-pollinating fruit trees

These include:

– Peaches

– Apricots

– Nectarines

Flower types for cross-pollination

• Dioecy (dioecious plants)– Example: Holly

Flower types for cross-pollination

• Dioecy (dioecious plants)– Example: Holly

Flower types for cross-pollination

• Monoecy (monoecious plants)– Example: Corn

Flower types for cross-pollination

• Dichogamy (monoecious plant flowering at different times)– Example: Squash

Male flower appears a few days earlier than female flower

Flower reproductive parts can be located away from each other

Ecotype

• A plant that has evolved in relation to its surrounding habitat

• Ex. Pseudotsuga menziesii– Coastal douglas fir– Rocky Mountain Douglas fir

Coastal Douglas fir

Rocky Mountain Douglas fir

Cline• A continuous variation in a species

• Ex. Acer rubrum (red maple)

Provenance

The geographic area

where a plant is

native to.

Controlling Genetic Variability

• Isolation

• Roguing

• Pure Stands

Controlling Genetic Variability

• Isolation

• Roguing

• Pure Stands

Controlling Genetic Variability

• Isolation

• Roguing

• Pure Stands