Exploring genotypic and
environmental influences
on crop quality
January 15, 2013
Canby, Oregon
Ted Radovich, Ph.D.
Sustainable Farming Systems Laboratory
Department of Tropical Plant and Soil Sciences
University of Hawaii at Manoa
theodore@hawaii.edu
Big = Blue Ribbon
A Shift in Focus
• Quality vs. quantity
• Antioxidants
• Eating quality
• “Superfoods”
• Farming for functionality and flavor
Color, flavor and human health
potential are chemically based, and
plant chemistry is influenced by both
genotype and environment.
Terroir
Variety
Cabernet Franc
Produce flavor and
Organic produce
nutrient content is
tastes better and is
dependent on how
better for you!
it's grown.
Crop Management and Quality
Examples from Ohio and Hawai'i:
– Head cabbage flavor
– Pakchoi phytonutrient content
– Hot pepper pungency
Glucosinolates
• Secondary metabolites in found in
cabbage family.
• Derived from amino acids
• Anti-carcinogenic
• Pungency, typical cabbage flavor.
Problem:
Buyers in Ohio began rejecting cabbage
that was perceived as too pungent.
How do growers produce cabbage with
low pungency?
Planting Date
May-planted cabbage
was higher in
glucosinolates than
June-planted across
years for all cultivars.
Radovich et al. 2005. HortScience 40:106-110.
Planting Date
The effect of planting
date and year was
attributed to the
number of days above
30 C during head
development
May ‘02
May ‘01
June ‘02
June ‘01
Planting Date
•Cultivars with high
glucosinolates
were more
pungent.
Radovich et al. 2005. HortScience 40:106-110.
Radovich et al. 2003. Acta Hort. 628:787-795
Irrigation
Plants receiving
irrigation during
head
development
were lower in all
glucosinolates.
Radovich et al. 2005. Journal of the American Society for
Horticultural Science 130: 943-949.
Irrigation
Irrigation effect on
glucosinolates was
attributed to the fraction of
evapotranspiration replaced
during head development.
Total
Brassicin
Managing phytonutrient content:
Pakchoi as model
• Glucosinolate, carotenoids, phenolics
•High value
Evaluate:
1.Response to compost tea
2. Aquaponic variety trials
32
Compost Tea
•Uses air and water
to extract:
• Nutrients
• Organic acids
• Microbes
• Ratio of water to
compost ranges
10:1-100:1
• Water is not
circulated, only air
• 12-24 hrs
32
Compost Tea
Oxisol
Mollisol
• Positively impacts growth.
• Glucosinolate and
carotenoid follow biomass.
• Effect is consistant across
soil and media.
• Response dependent on
rate and quality of
compost.
• Aeration and additives not
necessary.
Pant et al. 2009. J.Sci.Food Agric.
Pant et al. 2011. Compost Science and Utilization.
Peat
Mechanisms
Growth response associated with improved nutrient
status associated increased root growth, increased
microbial activity and added nutrients (Pant et al.,
2012).
9
Phenolics and antioxidant activities
were higher under very low nitrogen
availability.
Carotenoids
Above ground dry weight (mg plant -1)
Total glucosinolates (mg kg -1 dw)
Total carotenoids (mg kg -1 dry weight)
Carotenoid and Glucosinolate content
increased with nutrient availability.
Glucosinolates
Above ground dry weight (mg plant -1)
29
Aquaponics
Aquaponics
Pakchoi variety trials at Waimānalo
•3 week old seedlings of
seven Pakchoi varieties were
transplanted 7/26/12 at the
Waimānalo Research Station.
• 4 reps, 6 plants per rep with
8 inch spacing between and
within rows.
• Effluent from 350 fish in a
650 gallon tank was
recirculated through 4'x48'
beds with black cinder media.
•Head weights were recorded
on 3 plants from each rep 28
days after transplanting. The
4th leaf from the center was
collect for mineral and
phytonutrients analyses.
Glucosinolate content
Total Phenolic content
It’s “Chile” in Hawai’i
‘Hawaiian’ type; C frutescens
Hot peppers are important
in Hawai’i.
Hot sauces, Asian-Pacific &
Latin Cuisine.
Hawaii has done some
breeding and selecting.
TAMU has extensive chile
breeding program.
No data on capsaicinoid
concentrations in peppers
grown under Hawaii
conditions.
‘Waialua’ Hot Pepper
TAMU Mild Habanero
It’s “Chile” in Hawai’i
‘Hawaiian’ type; C frutescens
‘Waialua’ Hot Pepper
Photo courtesy Dr. Kevin Crosby
TAMU Mild Habanero
Range of Capsaicinoid
Concentration
Habanero
Jalapeño
Hawaiian & Thai types
Take Home Message
• Variety is the most useful tool to
maximize quality.
• Stress can increase concentrations of
some phytonutrients but decease yield
• Minimize stress to optimize yield and
quality.
Acknowledgements
•Kleinhenz Lab (OSU)
•Crosby Lab (TAMU)
• Talcott Lab (TAMU)
•Hue Lab (UHM)
• UH Aquaponics Lab
•Archana Pant
•Jensen Uyeda
• Amjad Ahmad
•Roger Corrales
•Servalano Lamer
•Craig Okazaki
•USDA Funding:
• OREI
• TSTAR
• WSARE
•Hatch
http://www.ctahr.hawaii.edu/sustainag/