Crop Genetics - Reproduction in Crop Plants

What does phenotype represent in plant breeding?

Phenotype = Genotype + Environment + (GxE) interaction

What is the formula that relates phenotype, genotype, and environment?

P = G + E + (G x E)

What are the two main categories of reproduction in crops?

Sexual and asexual reproduction

What reproductive modes fall under sexual reproduction in plants?

Self-fertilization (autogamy) and cross-fertilization (allogamy)

What is vegetative propagation?

A form of asexual reproduction using stem cuttings, tubers, suckers, bulbs, runners, etc.

Name three crops commonly propagated vegetatively.

Cassava, sweet potato, sugarcane (Bananas by suckers; potatoes by tubers)

What is apomixis in plants?

Asexual seed formation without meiosis or fertilization, resulting in clonal offspring

Give examples of apomictic species.

Citrus and many perennial forage species

What two key processes define sexual reproduction in angiosperms?

Meiosis and fertilization

What are the multicellular generations in plant life cycles?

Sporophyte (diploid) and gametophyte (haploid) generations

What do sporophytes produce, and via what process?

Produce spores via meiosis

What do gametophytes produce, and via what process?

Produce gametes via mitosis

In flowering plants, where are male and female gametophytes found?

Male in pollen grain; female in the embryo sac within the ovule

Why is reproductive mode important in breeding?

It determines methods used to develop improved cultivars

How does asexual reproduction benefit crop improvement?

It allows for fixing desirable traits in clones quickly

What’s special about breeding in vegetatively propagated crops like cassava?

Transformed traits can be immediately fixed without need for inbreeding/backcrossing

Self-pollination is also known as…?

Autogamy

Cross-pollination is also known as…?

Allogamy

Example of self-pollinating species mentioned?

Soybean

What enforces self-pollination in some flowers?

Physical traits like closed flowers, early anther dehiscence, or stigma obstruction

Vegetative reproduction forms genetically identical individuals known as…?

Clones

What process bypasses meiosis entirely?

Apomixis

Which process is referred to as clonal seed production?

Apomixis (agamospermy)

What reproduction type involves runners, rhizomes, suckers?

Vegetative (asexual) reproduction

Name a vegetatively propagated grass species mentioned.

Elephant grass (Napier grass)

What’s the reproductive advantage of apomictic cultivar development?

Enables fixing elite traits via clones through seed

What does “G x E” stand for in breeding?

Genotype x Environment interaction

Why are both meiotic and mitotic processes important in sexual reproduction?

Meiosis generates genetic diversity in gametes; mitosis develops gametophytes and sporophytes

What is the result of fertilization in angiosperms?

A diploid zygote that develops into sporophyte

Why is reproduction mode fundamental to cultivar development?

It determines breeding strategies suited to the crop