2016  OSU  Kabocha/buttercup  production  and  storage  trial  results.      

4/2017  

The  goal  of  this  project  is  to  identify  high-­‐yielding,  long  storing  and  delicious  kabocha,  buttercup,  and  other  winter  squash  varieties  for  production  on  Willamette  Valley  fresh  market  vegetable  farms.    Sixteen  varieties  of  kabocha  and  buttercup  squash  were  grown  at  four  planting  densities  in  a  replicated  field  experiment  at  the  Oregon  State  University  research  farm  in  2015  and  2016.  Data  was  collected  on  fruit  size,  yield,  flavor,  resistance  to  storage  rots,  and  duration  of  storage.    In  2016  only,  the  same  16  varieties  were  grown  under  dryland  conditions  in  a  separate  replicated  field  experiment.      

In  2015  the  OSU  experiment  was  managed  conventionally.  In  2016  it  was  managed  on  conventional  land  using  organic  practices  (with  the  exception  of  cucumber  beetle  management  –    a  synthetic  pesticide  was  applied  several  times  as  populations  are  very  large  on  this  farm).    There  is  insufficient  certified  organic  land  at  the  Corvallis  research  farms.  Single-­‐density  replicated  on-­‐farm  trials  were  also  conducted  on  two  organic  farms  both  years.  This  article  primarily  reports  on  the  methods  and  results  from  the  OSU  research  station  trial.  

The  irrigated  experiment  was  a  repeat  of  a  2015  experiment.    

METHODS  

Varieties  

Pictured  below  are  the  16  varieties  trialed  in  2016.    For  a  detailed  description  of  each  variety’s  characteristics,  botanical  category,  origin  and  size,  please  see  the  results  page  from  2015.      

 

Design  and  Management  

Irrigated  Trial  -­‐  Each  variety  was  grown  at  4  densities  with  4  replications  in  a  replicated  complete  block  design.    Squash  transplants  were  grown  in  the  greenhouse  and  transplanted  into  the  field  on  May  25th.    Rows  were  planted  on  5  ft  centers;  density  varied  by  in-­‐row  spacing  (9  in,  1  ft,  1.7  ft  and  2.5  feet  between  single  plants).    The  plants  received  1  inch  of  supplemental  water  once  per  week  via  overhead  irrigation.      

Dryland  Trial  –  Each  variety  was  grown  at  4  densities  with  3  replications  in  a  replicated  complete  block  design.    Seeds  were  direct  sown  in  the  field  on  May  11th.    Rows  were  planted  on  7.5  ft  centers;  density  varied  by  in-­‐row  spacing  (1  ft,  1.5  ft,  2.4  ft,  and  3.75  feet  between  single  plants).    The  field  was  watered  once  after  seeding  and  was  not  irrigated  afterward.      

Field  Maps  IRRIGATED  EXPERIMENT:  2015  and  2016.    4  densities  and  4  replications.    Rows  on  5  ft  centers.    9  in,  1  ft,  1.7  ft,  and  2.5  feet  in-­‐row  spacing  

 

   

5 10 15 20 25 30 35 40 45 50 55 5 5 10 15 20 25 30 35 40 45 50 55

1514 6 2 13 5 15 10 13 2

101 13 7 5 7 7 15 9 16

259 11 12 15 2 9 6 5 11

1014 15 4 9 9 11 8 3 2

353 8 5 1 9 7 3 14 16

1010 8 3 16 10 12 5 14 13

4510 16 7 4 10 1 4 8 12

102 6 12 11 3 1 10 4 6

50 block  1 5 block  2

6013 5 11 6 11 4 8 10 13

106 2 10 8 1 16 9 15 7

7014 15 10 3 1 7 15 12 16

1016 11 12 3 4 13 14 11 4

808 2 9 4 7 1 2 9 3

104 14 9 15 11 6 8 12 5

9016 12 7 1 3 14 5 11 6

1013 1 7 5 5 10 1 2 3

95 5

115 10

120 5

1308 6 3 14 8 2 8 16 12 10 16 2 6 8 6 13 15 2 6

1402 1 7 9 6 9 5 15 1 10 11 4 10 3 8 1 7 8 9

15012 5 11 16 4 13 4 7 14 10 14 7 9 1 2 11 10 16 3

16015 4 13 10 11 10 6 3 11 10 15 5 12 13 3 5 4 12 14

165 block  3 5 block  4

17010 6 3 1 2 6 2 10 8 10 3 8 12 9 10 6 5 2 14

1809 14 4 7 5 16 11 12 3 10 7 15 14 2 6 10 11 1 15

1905 15 13 11 4 4 14 9 15 10 11 5 6 4 1 7 8 12 13

2008 2 16 12 7 13 1 7 5 10 10 1 13 16 9 3 4 16 9

205 5

Golden

 G  4  plants/plot

Hone

y  Bear  4  plants/plot

DRYLAND  EXPERIMENT:  2016.    4  densities  and  3  replications.  Rows  on  7.5  ft  centers  1  ft,  1.5  ft,  2.4  ft  and  3.75  feet  in-­‐row  spacing  

 

 

 

Data  Collection  

Fruits  were  harvested  during  the  week  of  August  29th  for  the  irrigated  trial  and  during  the  week  of  September  5th  for  the  dryland  trial.    All  fruit  from  each  plot  were  weighed  and  counted  at  harvest.    Fruit  were  stored  in  three  locations:  a  walk-­‐in  cooler  with  dehumidifier  that  was  maintained  at  50-­‐55o  F  and  approximately  60%  relative  humidity,  a  closed  garage  kept  above  freezing  air  temperature,  and  an  open  barn  bay  (squash  from  the  open  bay  were  moved  into  a  closed  barn  bay  from  mid  December  through  early  January).    Fruit  were  evaluated  monthly  from  September  2016  through  March  2017  for  percent  rotten  or  otherwise  unmarketable  fruit  (e.g.  soft  or  wrinkled),  and  a  subsample  was  evaluated  for  external  and  internal  color,  degrees  Brix,  and  percent  dry  matter.  A  chef  evaluated  some  of  the  varieties  for  sensory  quality  on  several  dates  (data  not  yet  available).      

 

 

 

Cream  of  the  Crop Honey  Bear Sweet  Reba

3 8 12 9 9 1 13 7 5ROAD

14 6 2 13 9 10 6 3 1

7 15 14 2 3 14 15 4 9 9 11 12 15 1 9 14 4 7

11 5 6 4 5 10 8 3 16 3 8 5 1 8 5 15 13 11

10 1 13 16 11 2 6 12 11 10 16 7 4 4 8 2 16 12

Honey  Bear Jester

6 2 10 8 4 10 2 5 14 8 6 3 14 7 16 11 12 3

16 11 12 3 1 6 1 11 15 2 1 7 9 11 4 14 9 15

4 14 9 15 7 7 8 12 13 12 5 11 16 3 13 1 7 5

13 1 7 5 8 3 4 16 9 15 4 13 10 2 6 2 10 8

Honey  Bear Cream  of  the  Crop

13 5 11 6 6 6 2 10 8 16 9 15 7 10 8 12 3 9

14 15 10 3 12 16 11 12 3 13 14 11 4 5 15 14 7 2

8 2 9 4 2 4 14 9 15 6 8 12 5 12 5 6 11 4

16 12 7 1 10 13 1 7 5 10 1 2 3 6 1 13 10 16

Greek  Sweet  Red Greek  Sweet  Red

Hilo  La

otian

Cream  of  the

 Crop

Sweet  D

umpling

Sweet  R

eba

Hone

y  Be

arDe

licata  Sugarlo

af

Hone

y  Be

ar

Jester

RESULTS  

Yield  

 

Irrigated  trial  squash  yields  were  higher  in  2015  compared  to  2016  for  all  varieties.    Yields  were  exceptionally  high  in  2015  due  to  the  very  hot  dry  summer.  The  2016  summer  was  much  cooler  with  some  humid  rainy  periods,  which  caused  an  early  powdery  mildew  epidemic  (starting  at  fruit  set)  which  reduced  yields.  Tetsukabuto  is  an  extremely  high  yielding  squash  and  also  powdery  mildew  resistant,  so  irritated  yields  were  high  in  2016  and  double  the  dryland  yield.  For  other  varieties,  however,  dryland  yield  was  comparable  to  2016  irrigated  yield  as  they  yielded  so  poorly  in  under  irrigation  in  2016.    These  varieties  include  Winter  Sweet,  Cha-­‐Cha,  and  Burgess.  Crown,  Gold  Nugget  and  Shokichi  Shiro  were  only  grown  in  2016    

On-­‐farm  Trials  

A  subset  of  the  varieties  grown  in  the  OSU  Kabocha/buttercup  trial  were  grown  on  three  on-­‐farm  trials  along  with  11  other  long  storing  winter  squash  varieties.    The  yield  results  from  two  of  the  farms  are  shown  below.      

 

 

 

 

 

 

 

 

 

 

 

 

Losses  to  Storage  Rots:  effects  of  production  and  storage  environments  

Extension  bulletins  recommend  storing  winter  squash  between  50  and  55o  F  and  60  to  70%  relative  humidity  to  avoid  chilling  injury,  but  in  informal  trials  squash  appeared  to  store  as  well  or  better  under  closed  barn  bay  conditions.    We  evaluated  the  impact  of  storing  all  varieties  in  three  different  storage  environments  on  losses  to  storage  rots  as  well  as  fruit  quality.    

The  Three  Storage  Environments  

 

 

Temperature  and  humidity  were  monitored  in  each  location.    The  following  figure  shows  the  temperature  in  each  location  from  November  through  March.    The  Walk-­‐In  environment  stayed  consistent,  while  there  was  more  fluctuation  in  the  other  two  environments.    The  squash  stored  under  Open  Bay  conditions  were  moved  temporarily  into  another  closed  bay  environment  (different  from  the  Closed  Bay,  and  maintained  at  a  slightly  lower  temperature)  from  mid  December  through  early  January  as  temperatures  were  expected  to  be  in  the  low  20s  during  that  period,  and  then  returned  to  the  open  bay.  Temperatures  in  the  Open  Bay  fell  to  below  freezing  in  January  resulting  in  a  catastrophic  loss  of  most  of  the  varieties  stored  there.      

 

The  squash  were  evaluated  monthly  for  storage  losses.    One  of  the  most  important  characteristic  of  winter  squash  varieties  is  whether  their  fruit  are  resistant  to  fruit  rots.  There  are  serious  squash  fruit  rotters  (soilborne  fungi)  in  the  Willamette  Valley.  Fruit  that  are  not  resistant  rot  soon  after  harvest.  Most  winter  squash  varieties  ARE  NOT  resistant  to  these  rots  so  should  not  be  grown  if  they  cannot  be  sold  immediately  after  harvest.  Another  important  characteristic  is  whether  or  not  the  fruit  is  long  storing  (can  maintain  eating  quality  for  a  long  storage  period).    

Squash  fall  into  4  general  storage  categories  

1. Very  rot  resistant  AND  long  storing  (Tetsukabuto  and  Winter  Sweet)  2. Moderately  rot  resistant  AND  long  storing  (Sweet  Mama)  3. Not  rot  resistant  but  long  storing  (Sunshine  -­‐  it  might  only  be  possible  to  store  these  if  grown  

dryland)  4. Not  rot  resistant,  not  long  storing  (Uncle  David,  don’t  grow  these  to  store!)  

Below  are  figures  representing  an  example  of  each  of  the  4  types  of  squash  listed  above.  The  y-­‐axis  shows  the  yield  (tons/acre)  at  harvest  (late  August)  and  as  the  squash  are  stored  throughout  the  fall  and  

winter.  Total  yield  is  adjusted  to  reflect  squash  storage  losses.  As  shown  in  the  figures,  Tetsukabuto  is  the  star  performer.  It  is  high  yielding,  completely  resistant  to  storage  rots,  and  long  storing.  Tetsukabuto,  interestingly,  lost  quality  due  to  dehydration  (not  storage  rots)  when  grown  dryland  and  stored  in  the  Walk  In.  Sweet  Mama  is  high  yielding  (it  yielded  better  in  2015  than  in  2016)  and  stores  well  into  December  when  grown  under  irrigation,  but  does  not  store  nearly  as  long  as  Tetsukabuto.  However,  Sweet  Mama  grown  dryland  in  2016  stored  as  long  as  Tetsukabuto.    Sunshine  is  high  yielding  but  very  susceptible  to  storage  rots  here  in  the  Willamette  Valley.  However,  it  was  less  susceptible  to  storage  rots  and  much  longer  storing  when  grown  dryland  in  2016.    Uncle  David  is  not  high  yielding,  rot  resistant,  or  long  storing  when  grown  here  in  the  Willamette  Valley.    

 

The  figure  below  shows  the  yield  at  the  time  of  harvest  minus  the  percent  loss  in  storage  in  late  January.