The first generation derived from crossing two different plants. The seeds from the F1 plant are not likely to produce plants exactly like the plant they came from. A blue flowering F1 hybrid might produce seeds that produce plants that flower in white or pink or some other color. p fairy ring:

First generation offspring derived from breeding two distinct pure-bred lines. They are vigorous and uniform plants. Seeds produced from F1 Hybrids will not come true to their parents.

A first generation hybrid of two different plants

A first generation cross between two stable parents. More vigorous and uniform than an ordinary hybrid. Does not breed true.

the first generation offspring created by cross-pollinating two different parent plants. These plants have good uniformity, yield, and vigour. Seeds saved from F1 plants will not produce plants that a [..]

the first generation offspring from two distinct, purebred plants; these plants are vigorous in growth and uniform in appearance; f1 stands for fist filial

The result of crossing two related, pure-bred plants with certain desirable characteristics. Also known as a first-generation hybrid.

 The first generation derived from crossing two different plants. The seeds from the F1 plant are not likely to produce plants exactly like the plant they came from. A blue flowering F1 hybrid might p [..]

  First generation of a hybrid cross between 2 different parental inbred          strains.  Genetically identical mice that are heterozygous at all loci.