Transcript CDC “New Crops” Program

Management of
Milk Thistle Quality
D. Waterer
J. Wahab
D. Cooper
CDC “New Crops” Research
• Objective
– Assist in the identification and
adoption of “New Crops”
suited to Saskatchewan
– Suitable growing conditions
and market opportunities ??
– Industry driven initiative
Milk thistle (Silybum marianum)
• Annual/biennial
• Indigenous to c. Asia but naturalized
worldwide
• Long history of medicinal use
• Hepato-protectant
• Identified by SHSA as “focus crop”
New Crops Program
Milk Thistle Research
• Objective – determine management
practices that maximize yields of high
quality milk thistle in Saskatchewan
• Good seed yields vs. Good quality ?
Milk Thistle Quality
• Silymarin complex + other bioactive
flavenoids
•
Silymarin complex = mixture of isomers
•
Silybinin, silychristine and silydianine
Milk Thistle Seed Quality
• Minimum of 2% silymarin complex ... higher
the better.
• Levels and mixture of isomers under genetic
and environmental control.
• Yields more heritable than quality
• Small positive correlation between yield and
quality
Managing for Maximum Yields ...
Impact on Quality ?
• Indeterminent flowering habit = uneven
ripening
• Quality improves with seed maturity
• Shatters once ripe = lost yields
•
Options
•
Hand harvests (multiple)
•
Machine harvest (once-over)
New Crops Program
Milk Thistle Research
• Germplasm evaluation trials (2003-2005)
• 30 lines from worldwide sources
• Assess for agronomic characteristics,
seed yields and quality
• Standard crop management practices
• Hand vs machine harvested
- Once-over machine
harvest = 80% of yields.
of multiple hand harvest
- Much faster and user
friendly.
2004 Milk Thistle Trials
Line
Silybinin A
(% w/w)
Silybinin B
(% w/w)
Other
Flavonolignans
Silymarin
(% w/w)
Hand
Combine
Hand
Combine
Hand
Combine
Hand
Combine
Austra
Hort
0.20
0.38
0.27
0.53
0.85
1.13
1.32
2.00
Bolier
0.38
0.37
0.53
0.52
1.03
1.29
1.94
2.18
Cruz
-
0.41
-
0.58
-
1.10
-
2.09
Genesis
0.05
0.05
0.05
0.06
0.56
0.85
0.64
0.95
Horizon
0.04
0.04
0.05
0.05
0.46
0.71
0.55
0.81
Johnny’s
0.08
0.04
0.10
0.05
0.74
0.54
0.93
0.62
Kalyx 1
0.27
0.37
0.38
0.52
0.89
1.18
1.52
2.07
Reddis
0.31
0.31
0.37
0.44
0.75
0.78
1.42
1.53
Richters
0.32
0.42
0.39
0.58
0.99
1.20
1.70
2.20
Royston
757PJ2
0.52
-
0.74
-
1.29
-
2.54
-
Royston
1236LJ-2
0.08
0.12
0.10
0.15
0.60
0.78
0.79
1.06
Royston
131-J2
0.30
0.18
0.35
0.21
0.79
0.64
1.44
1.02
TMP
14068
0.04
0.05
0.05
0.05
0.64
0.61
0.73
0.71
0.20
0.23
0.28
0.31
0.80
0.90
1.29
1.43
Mean
2004 - Milk Thistle Trials
Line
Seed Yie ld
(kg/ha)
Silymarin
content
(%)
Silymarin Yield
(kg/ha)
Austra Hort
1337
1.7
22.4
Bolier
1254
2.0
25.0
Genesis
823
0.7
5.7
Horizon Herbs
656
0.7
4.6
Johnny’s
643
0.6
5.0
Kalyx 1
1151
1.6
18.4
Richters
870
2.0
17.4
Royston
Lot 1236 LJ2
1007
0.9
9.0
TMP 14068
1362
0.7
9.5
Milk Thistle Germplasm Trials
• Huge genetic variability in yield
potential and quality
• Significant year to year variability in
yields and quality … but relative
performance of lines is fairly stable.
• Weak positive correlation between
yields and quality
• Machine harvest is efficient and yields
a high quality product
Managing for Maximum Yields ...
Impact on Milk Thistle Quality ?
• Fertility
– Literature shows minimal impact on either
yields or quality
– Confirmed by Wahab in SK in 2003 and
2004.
– Good news for organic growers
Managing for Maximum Yields ...
Impact on Quality ?
• Plant Populations
– Literature shows minimal impact of
population on either yields or quality
– Confirmed by Wahab in SK in 2003 and 2004.
– Good news due to high
seed costs
- Suggests potential for
fall seeding
Managing for Maximum Yields ...
Impact on Milk Thistle Quality ?
• Timing of Harvest
– Literature shows yields peak with maturity … then
decline due to shattering.
– Desiccation facilitates harvest … impact on yields
and shattering = ???
– Desiccation options
• Chemical desiccants = not organic
• Organic desiccants (vinegar)
• Frost = dependability ?
– Wahab tests impact of timing of desiccation and type
of desiccant on yields and quality in 2003 and 2004.
Managing for Maximum Yields ... Impact on Quality ?
• Timing + Method of Desiccation Studies
– Results vary depending on crop maturity at
time of desiccation = growing season
effects.
– Chemical desiccants work faster than
organic options
– Fast action of chemical desiccants allows
delayed treatment = increased yields and
improved quality in short seasons
Other Options for Improving
Milk Thistle Quality
• Seed Grading
– Relatively easy to grade for seed
size
– Can achieve significant
improvements in quality (%
silymarin) by sizing = blending
options.
– Color sorting is slower, not as
effective and complicated by line
to line variability in seed color.
Maximizing Milk Thistle
Yield and Quality
• Conclusions
– Germplasm selection is critical
• Significant genetic variability in yields and quality
• Line performance is relatively stable across years/sites.
– Standard management variables (fertility, plant spacing,
irrigation) have little impact on yields or quality
– Must time harvest for maximum seed maturity without
excessive losses to shattering.
– Mechanical harvest does not compromise quality.
– Desiccation options vary in efficacy
– Potential to improve/standardize quality through postharvest grading steps.
Maximizing Milk Thistle
Yield and Quality
• Conclusions
- with better management and handling practices,
significant improvements in yield are possible.
- with better management practices ... higher and
more predictable levels of active ingredients are
possible
- higher yields and quality at lower cost = crucial in a
competitive market