Over the last thirty years, there’s been a different kind of gold rush in the hills of the central valley.  Mandarin Oranges have gone from a specialty and highly seasonal fruit item to a staple of produce departments and lunchboxes, available from California for almost six months of the year.  I think most fruit lovers don’t have any idea how many different varieties are grown, and how much work plant breeders and farmers have done to make this wonderful fruit so widely available.  I don’t have the space or time here to tell even close to the whole story.
Most people know “Cuties” and “Halos”, the most widely available name brands of seedless mandarin.  But these names and their accompanying logos are not varieties — they are trademarked brand names of the companies that pack them.  Depending on when you buy them, either type can be one of five or six separate varieties.  While they may look similar, they can taste completely different.
The majority of the “brand-name” mandarins are Clementines — a subset of mandarins that originated in Northern Africa.  They are relatively bland, and produce well only in the Southern part of the San Joaquin Valley where there is less rainfall and cold then farther north.
The first seedless mandarins planted in Northern California were Satsumas — which again is a subset of mandarin that includes several varieties — all of which originated in Japan and China.  The most common is the November-January ripening Owari, which is the variety we grow.  In general Satsumas have a higher acid content than Clementines and a richer flavor.  They are also far more tolerant of cold weather due to their northern Asian genetics.  Satsumas have a relatively long history in the Sacramento Area, especially in the foothill region.  Our orchard was planted over 40 years ago; compare that to most of the Clementine orchards in the San Joaquin Valley that were planted in the 1990s or later.
Until fairly recently, “mandarin season” was a short one — beginning in the fall and ending in January.  Plant breeders have focused for many years on creating hybrid varieties to extend the season through winter and into spring, but the process of identifying good candidates for commercialization is a slow one.  Citrus trees take 4-6 years just to start producing fruit, and it can take 10 years before a variety can be adequately evaluated for commercial use.  Once farmers start to plant them in large numbers, another ten years will pass before the variety becomes widely available to consumers.
Back in the 1980s, citrus growers in California got very excited about a spring ripening seedless mandarin variety imported from Morocco.  It was only once thousands of acres of the tree were planted that farmers realized that the variety was seedless only in the total absence of bees.  Orchards had to be netted or isolated from almonds (which require bees for pollination), or the fruit would be full of seeds and thus worthless commercially.  Very few acres of that mandarin variety still remain in production.
When we sought to extend our seedless mandarin season in 2006, the University of California had recently released several late winter- and spring-ripening varieties that seemed promising.  We planted 600 trees of each in 2006.  One of those varieties was poorly suited to our cold winters, and suffered extensive freezing damage over a number of years before we finally removed the trees.  The other ended up meeting all of our needs:  it was tolerant of our colder winters, it produced very well, and the fruit was exceptionally tasty.  It’s name is Tahoe Gold.  While the variety did not end up becoming a widely popular variety with growers, its visual appeal and very distinct flavor make it a great niche crop for a small farm like ours.
Terra Firma’s experiment in extending our seedless mandarin season is a common one for citrus growers in California.  Different varieties grow and produce differently in different areas.  They even taste different.  For the educated citrus eater, this provides a culinary and shopping opportunity to explore and find their favorite fruits.