Breeding%20Vegetables%20for%20Optimum%20Levels%20of%20Phytochemicals - PowerPoint PPT Presentation

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Title: Breeding%20Vegetables%20for%20Optimum%20Levels%20of%20Phytochemicals


1
Breeding Vegetables for Optimum Levels of
Phytochemicals
Kevin Crosby Texas AM University
2
Plant Breeding
  • Application of genetic theory, including
    molecular biology to develop improved plant
    cultivars
  • Vegetables are high priority crops in Texas and
    USA- numerous cultivars from diverse breeding
    programs 15 billion in USA

3
Definitions
  1. ANY HUMAN HANDLING OF PLANTS WHICH GENETICALLY
    ADAPTS THEM TO THE SERVICE OF MEN.
  • THE ART OF SELECTION BASED UPON THE SCIENCE OF
  • GENETICS.

C. EVOLUTION DIRECTED BY THE WILL OF MAN.
(Vavilov, 1935)
4
Wild Types vs. Improved
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8
Foods for Health
  • Elevated levels of flavonoids, carotenoids,
    ascorbic acid, minerals, pectins
  • Traditional plant breeding- exploitation of
    naturally occurring genes in the germplasm
  • Gene mapping and genetic transformation-
    increased Ca, vitamin C, ß-carotene

9
Pepper Phytochemicals
  • Peppers are good source of important human health
    related compounds
  • Carotenoids, flavonoids, ascorbic acid, capsaicin
  • Great genetic variation within pepper germplasm
    at different maturity stages

10
Dietary Fiber in ½ cup Serving
Green Peppers- raw 2.4
Hot Red Peppers- raw 19.2
Hot Red Peppers- dried 57.6
Pinto Beans- cooked 9.4
Prunes- dried 3.8
Tomatoes- raw 1.4
Spinach- cooked 7.0
Squash- cooked 3.0
11
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12
Screening Germplasm
  • Planted 60 diverse pepper lines at Weslaco and
    Uvalde
  • Harvested green and red mature fruit
  • Analyzed Vit C by HPLC for replicated samples

13
High Vitamin C
  • Peproncinis- high at all locations, 557 ppm
    (green) to 2377 ppm (red)
  • Pasilla, Anaheim, Marconi and Ancho also very
    high at red stage- 1900-2280 ppm
  • TAM B36- Tropic Bell, highest at green stage 600
    ppm 60 mg/100g

14
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15
TAM Pasilla VR
16
Cultivar B 36 (GR-RD) Vitamin C 1758-2082
ppm Flavonoid 6-13 ppm
17
High ß-carotene
  • Highest in red chile/paprika- C127 (2330 µg/100g)
    38 RDA, Fidel orange chile (2366)
  • Almost none in many wax and hot types
  • TMJ2 (1242 µg/100g) gt Grande (850)

18
Cultivar C 127 Vitamin C 1721 ppm Flavonoid
45 ppm Beta-Carotene 23.3 ppm
19
Habanero ß-carotene
TAM Mild- 760 µg/100g
Yucatan- 20 µg/100g
20
Fresh fruit vitamin C and beta-carotene contents
of melons from Weslaco
Vitamin C
?-carotene Cultivar/line
(mg100g-1)x
(µgg-1)x Fruit type
TAM Perlita 45 21.7 az 62.2 az Western shipper- size 15y
TAM Uvalde 15.2 b 57.5 ab Western shipper- size 18
Explorer 12.4 bc 45.0 cde Western shipper- size 15
Cruiser 12.1 bc 36.3 e Western shipper- size 12
Mission 11.9 bc 40.3 de Western shipper- size 15
Green Ice 11.8 bc 4.70 f Honeydew- size 15
TAM Mayan 11.2 bcd 11.5 f Casaba- size 12
Gold Mark 10.8 bcd 41.4 cde Western shipper- size 12
TXC 2015 10.0 bcd 49.8 bc Western shipper- size 12
HMX 9583 9.4 cd 46.0 cd Western shipper- size 12
Valley Gold 9.3 cd 48.5 bcd Western shipper- size 12
Mainpak 9.2 cd 43.5 cde Western shipper- size 12
Pronto 8.0 cd 43.0 cde Western shipper- size 12
TAM Dew Impr. 7.2 cd 4.70 f Honeydew- size 12
Primo 7.0 cd 56.7 ab Western shipper- size 12
zMean separations by LSD, P 0.05. Values
followed by the same letter are not significantly
different. ySizes based on number of fruit which
fit into a standard melon packing box. xBased on
fresh weight.
21
Selection Process
  • Choose the best parents for target traits
  • Controlled pollinations to create new families
  • Selection for traits by combined quality
    analyses- field and lab
  • Backcrossing or inbreeding to fix key genes

22
Controlled Pollination
23
Developing a New Melon
  • Industry wants larger cantaloupes with good
    flavor and disease resistance
  • We had excellent flavor, disease resistance, Vit
    C, carotene in TAM Uvalde
  • So we crossed it with Cruiser (very large, high
    yield but poor flavor, carotenoids)

24
Chujuc Muskmelon
  • Large, round fruit, Sz 9-12
  • High yield and resistant to PM
  • High in beta-carotene Vitamin C, sugars

25
Genetic Linkage Mapping
  • Develop population which segregates for gene(s)
    of interest
  • Carefully measure phenotype of trait for each
    plant and parents
  • Screen DNA for molecular markers which are linked
    to the trait (gene)

26
DNA Marker Linkage
RAPD marker OAC09.900 expressing polymorphism
between two DNA bulks from high and low
beta-carotene F2 plants. 1 Sunrise (low
parent), 2 TAM Uvalde (high parent), 3 DNA
bulk from low beta-carotene F2 plants, 4 DNA
bulk from high beta-carotene F2 plants, and 5 a
100-bp DNA marker ladder.
27
1 2 3 4 5
-1500bp -600bp -300bp
OAU02.600
Figure 5. RAPD marker OAU02.600 expressing
polymorphism between two DNA bulks from high and
low ascorbic acid F2 plants, and between Dulce
and TGR1551. 1Dulce, 2TGR1551, 3DNA bulk
from high ascorbic acid F2 plants, 4DNA bulk
from low ascorbic acid F2 plants, and 5molecular
size marker.
28
Molecular Markers in Pepper
  • Family of high flavonoid CA377 x high vitamin C
    B22
  • F2 progeny, F1 progeny, Parents grown in two
    environments for mature fruit
  • Screening with RAPD markers in bulks and
    genotyping each F2 progeny
  • Constructing genetic linkage map

29
High Antioxidant Parents
TAES B22
CA 377
F1 Hybrid
30
1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20 M
OL07.2050
-2072bp
OL07.1700
OL07.1500
-1500bp
OL07.1100
OL07.800
-600bp
OL07.520
OL07.480
-300bp
Fig. 1. Segregation of seven RAPD markers in an
F2 population derived from the pepper cross of CA
377 x B 22. 1 to 20F2 plants of the CA 377 x B
22 cross and Ma 100-bp DNA marker ladder.
31
Current Progress
32
Flavor is Crucial
  • Many people complain about tomatoes
  • Long shelf life and green harvested fruit just do
    not taste very good
  • Enhancing fresh market consumption and
    profitability for growers requires change

33
New Breeding Priorities
  • Screen germplasm for best tasting tomato
    cultivars, lines, landraces
  • Cross with TAMU heat-tolerant, disease resistant,
    high yielding breeding lines
  • Developed better tasting, adapted cultivars

34
Improved Heirloom Types
Introgressed virus, fusarium and heat resistance
genes developed more compact plants adapted to
staked culture
35
Flavor Trumps Appearance
36
Why Vegetable Genetics?
  • Vegetables are excellent source of key human
    health related phytochemicals
  • 15 billion component of US agriculture
  • Not all cultivars are equal- flavor and
    appearance are also crucial
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