A crop that is self-fertilized (self-pollinated) over successive generations produces what is known as a pure-line variety. In self-fertilizing crops, pollen from a flower fertilizes the ovule of the same flower or another flower on the same plant. Over many generations of self-fertilization, the offspring become increasingly homozygous (genetically uniform), producing a true-breeding line where parents and offspring are virtually identical for key traits.
Examples of self-fertilizing crops include rice, wheat, cowpea, groundnut, tomato, and soybean.
The other terms have different meanings:
A mutant is an organism that has undergone a sudden, heritable change (mutation) in its genetic material. This is not related to the method of fertilization.
A hybrid is the offspring produced by crossing two genetically different parents (cross-fertilization), which is the opposite of self-fertilization.
Recessive describes a type of gene allele that is expressed only when two copies are present (homozygous recessive). It is a genetic term for allele behaviour, not a type of crop.
Exam tip: Self-fertilization leads to homozygosity and pure lines. Cross-fertilization leads to heterozygosity and hybrids.
