Breeding Vegetables for Optimum Levels of Phytochemicals Kevin

Breeding Vegetables for Optimum Levels of Phytochemicals Kevin Crosby Texas A&M University

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

Definitions A. ANY HUMAN HANDLING OF PLANTS WHICH GENETICALLY ADAPTS THEM TO THE SERVICE OF MEN. B. THE ART OF SELECTION BASED UPON THE SCIENCE OF C. GENETICS. C. EVOLUTION DIRECTED BY THE WILL OF MAN. (Vavilov, 1935)

Wild Types vs. Improved

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 transformationincreased Ca, vitamin C, β-carotene

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

Dietary Fiber in ½ cup Serving Green Peppers- raw 2. 4 Hot Red Peppers 19. 2 raw Hot Red Peppers 57. 6 dried Pinto Beans- cooked 9. 4 Prunes- dried 3. 8 Tomatoes- raw 1. 4 Spinach- cooked 7. 0 Squash- cooked 3. 0

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

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 B 36 - Tropic Bell, highest at green stage: 600 ppm= 60 mg/100 g

TAM Pasilla VR

Cultivar: B 36 (GR-RD) Vitamin C: 1758 -2082 ppm Flavonoid: 6 -13 ppm

High β-carotene • Highest in red chile/paprika- C 127 (2330 µg/100 g) 38% RDA, Fidel orange chile (2366) • Almost none in many wax and hot types • TMJ 2 (1242 µg/100 g) > Grande (850)

Cultivar: C 127 Vitamin C: 1721 ppm Flavonoid: 45 ppm Beta-Carotene: 23. 3 ppm

Habanero β-carotene TAM Mild- 760 µg/100 g Yucatan- 20 µg/100 g

Fresh fruit vitamin C and beta-carotene contents of melons from Weslaco Cultivar/line Vitamin C (mg· 100 g-1)x -carotene (µg·g-1)x Fruit type TAM Perlita 45 21. 7 az 62. 2 az Western shipper- size 15 y 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 TXC 2015 10. 0 bcd 49. 8 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 Primo 7. 0 cd 56. 7 ab z. Mean cde Western shipper- size 12 bc Western shipper- size 12 f Honeydew- size 12 Western shipper- size 12 separations by LSD, P ≤ 0. 05. Values followed by the same letter are not significantly different. based on number of fruit which fit into a standard melon packing box. x. Based on fresh weight. y. Sizes

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

Controlled Pollination

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)

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

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)

DNA Marker Linkage 1 2 3 4 5 -1500 bp OAC 09. 900 -600 bp RAPD marker OAC 09. 900 expressing polymorphism between two DNA bulks from high and low beta-carotene F 2 plants. 1 = Sunrise (low parent), 2 = TAM Uvalde (high parent), 3 = DNA bulk from low beta-carotene F 2 plants, 4 = DNA bulk from high beta-carotene F 2 plants, and 5 = a 100 -bp DNA marker ladder.

1 2 3 4 5 -1500 bp OAU 02. 600 -600 bp -300 bp Figure 5. RAPD marker OAU 02. 600 expressing polymorphism between two DNA bulks from high and low ascorbic acid F 2 plants, and between ‘Dulce’ and TGR 1551. 1=’Dulce’, 2=TGR 1551, 3=DNA bulk from high ascorbic acid F 2 plants, 4=DNA bulk from low ascorbic acid F 2 plants, and 5=molecular size marker.

Molecular Markers in Pepper • Family of high flavonoid CA 377 x high vitamin C B 22 • F 2 progeny, F 1 progeny, Parents grown in two environments for mature fruit • Screening with RAPD markers in bulks and genotyping each F 2 progeny • Constructing genetic linkage map

High Antioxidant Parents TAES B 22 CA 377 F 1 Hybrid

1 OL 07. 2050 OL 07. 1700 OL 07. 1500 OL 07. 1100 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 M -2072 bp -1500 bp OL 07. 800 OL 07. 520 OL 07. 480 -600 bp -300 bp Fig. 1. Segregation of seven RAPD markers in an F 2 population derived from the pepper cross of CA 377 x B 22. 1 to 20=F 2 plants of the CA 377 x B 22 cross and M=a 100 -bp DNA marker ladder.

Current Progress

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

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

Improved Heirloom Types Introgressed virus, fusarium and heat resistance genes; developed more compact plants adapted to staked culture

Flavor Trumps Appearance

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