Grapevine  varie*es,  trellis  systems,    and  mechaniza*on  of  the  California  

raisin  industry  

Ma:hew  Fidelibus  

Vi*culture  and  Enology  UC  Davis  

Outline  

•  Overview  of  CA  raisin  industry  •  Tradi*onal  produc*on  methods  

•  Mechaniza*on  op*ons  for  tradi*onal  vineyards  

•  Newer  dry-­‐on-­‐vine  (DOV)  systems  

•  Future  goals  

California  Raisin  Industry  

•  140  year  history  •  Located  ~  60  mile  radius  around  Fresno  in  SJV  

•  90%  natural  sun-­‐dried  

•  ~170,000  acres  

•  ~340,000  tons  dried  raisins/yr  

California  Raisin  Industry  

•  Small  family  farms;  ~40  ac  mean  size  

•  Historical  10-­‐15%  ROI  +  land  apprecia*on  

Varie*es  

THOMPSON SEEDLESS

Problems  with  Tradi*onal  Raisin  Produc*on  

•  Labor  intensive  •  Fruit  laid  on  ground  •  Produc*vity  limits  

Op*ons  for  growers  with  tradi*onal  Thompson  vineyards  

•  Dry-­‐on-­‐vine  (DOV)  •  Con*nuous  tray  

     

Con*nuous-­‐Tray  

•  Harvest  pruning  (HP)  facilitates  abscission;  minimizes  ‘juicing’  

•  Harvester  removes  green  fruit  

•  A  layer  of  green  berries  are  spread  on  paper  ‘tray’  that  runs  the  length  of  the  row  middle  

•  Berries  dry  as  in  tradi*onal  trays  •  Raisins  collected  with  a  pick-­‐up  machine  

Fresno N

umbe

r of

occ

urre

nces

August September October

½ Aug. = 2

½ Aug. = 2

½ Aug. = 0

½ Aug. = 0

Sept. total = 12

Sept. total = 12

Sept. total = 0

Sept. total = 0

0.24”

.01”

0.74”

.25”

.75”

½ Oct. = 5

½ Oct. = 3

½ Oct. = 0

½ Oct. = 8 Sum, all

Dry  on  the  Vine  (DOV)  

Dried  on  the  Vine  (DOV)    Raisin  Produc*on    

•  Eliminates  the  need  to  hand  harvest  and  lay  fruit  on  paper  trays  

•  Requires  that  fruit  bearing  canes  be  severed  at  harvest  

Thompson  Seedless  DOV  Systems  

•  Tradi*onal  trellis  •  South-­‐side  

South  Side  Systems  

+  Exis*ng  Thompson  Seedless  acreage  Equipment  availability  

–  Yield  limita*ons  Trellis  modifica7on  

Can  Thompson  Seedless  be  dried  on  the  vine  in  CA?  

•  Yes,  and  harvest  costs  can  be  reduced,  but  late  maturity  makes  adequate  drying  difficult  and  yield  poten*al  is  limited  

•  Varie*es  that  ripen  earlier  than  Thompson,  on  more  expansive  training  and  trellising  systems,  are  required  for  op*mal  DOV  produc*on  efficiency  

Fiesta DOVine Thompson Seedless Selma Pete

All canes severed 8/14/01, pictured 9/10/01

DOV  Raisin  Varie*es  

BLACK CORINTH (ZANTE CURRANT)

FIESTA

DOVine

SELMA PETE

SUMMER MUSCAT

DIAMOND MUSCAT

Open  Gable  

•  Large  Y-­‐shaped  trellis  supports  larger  canopy  •  Increased  yield  poten*al–  about  twice  as  produc*ve  as  standard  trellising  on  a  per  acre  basis  

•  Decrease  harvest  cost,  but  increased  pruning  costs  and  significant  investment  for  trellis  installa*on  required    

OVERHEAD  ARBOR  

•  2.5  to  3  *mes  as  produc*ve  as  conven*onal  trellis  systems  

•  Not  well  suited  for  Thompson  Seedless  or  other  mid-­‐season  cul*vars  

•  Significant  investment  required  

Changes  in  raisin  produc*on  methods  

Area  planted  to  raisin  grapes  declining,  and  becoming  increasingly  

mechanized  

California  Raisin  Industry  

•  DOV  produc*on  

•  New  cul*vars  &  trellis  systems  

•  Corporate  farms  

•  Fewer  acres  

Future?

Acknowledgements  

•  L.  Peter  Christensen,  Stephen  Vasquez  (UC)  •  David  Ramming  (USDA-­‐ARS)  

•  Earl  and  Randy  Rocca  (Rocca  Ranches)  •  California  Raisin  Marke*ng  Board