Definition - What does Cross mean?
In genetics, a cross is the breeding of two parents with different genes that produce offspring that have characteristics of both parents. In plant biology, the two parent plants have to be closely enough related to be genetically compatible. For example, they might be similar varieties of plants or species close enough related that they can breed.
In cannabis cultivation, a cross is a strain of marijuana that has been created deliberately by crossing two carefully selected parent plants to achieve a more highly valued offspring. This is how new marijuana strains continue to enter the market.
A cross can have parents that are both sativas, both indicas, or a blend of both.
Hydrolife explains Cross
Cannabis plants are dioecious, which means that the male and female parts are on different plants. Carefully cultivated strains can create crosses specially chosen for any number of reasons.
After selecting for dominant and recessive traits, the grower can create their own personal (signature) strain. Two plants with green buds might cross and make pink buds, meaning that was a recessive trait. Other traits growers cross for include terpenes, which give certain strains such as Jaegermeister or Mango Kush their trademark smell.
Another way to describe a cross is to use the term 'hybrid'. Crossing plants results in hybrids. Cannabis genetics tend to get confusing for someone just starting out, but once you know the basics it's quick to figure out.
Making a cross involves allowing a male plant to go to flowers and pollinate a female plant. Ideally the pollen should be sprinkled on a female plant from two to four weeks into flowering. The female will make seeds and these seeds will be a combination of the parent plants.
Carefully selecting phenotypes create crosses and strains with different traits. Some might flower quickly, have especially large buds, be suited for a particular climate, or have a lot of THC. Marijuana continues to grow in more potent and colorful varieties as a result of crosses.