Breeding Schemes for Cross-Pollinated Crops

Marijuana Horticulture

by Jorge Cervantes

There are many types f breeding programs, some more complex than others. Which breeding method to employ depends entirely on the breeder’s goal. Ideally, potential breeders understand the benefits and drawbacks of each strategy, so a suitable strategy can be chosen to achieve the desired goal. The breeder’s personal preference always comes into play when choosing a breeding program. Previous successes may influence a breeder to use one specific breeding strategy over another. Some breeders rely heavily on science and statistics when analyzing the performance of their hybrids or progeny. Others consider breeding more of an art, and select based on feeling. Over the course of a breeding program, a breeder will often use more than one method to achieve various aspects of the goal.

When breeding cross-pollinators, we discuss hybrid performance in terms of combining ability – the ability of an inbred line to give characteristic performance in hybrid combinations with other lines. The progenies are tested for performance as populations and related back to the parental generation. Some often-used measures of performance are general combining ability (CGA) and specific combining ability (SCA). General combining ability is the average or overall performance of a given line in hybrid combinations open-pollinated with other lines.

Specific combining ability is the performance of a specific line, as compared to other lines, when crossed with the same specific pollen source.