Groundnut and Cassava

The underground mystery:

What can a breeder do?

S. P. Tallury

Department of Crop Science

NC State University

Raleigh, NC 27695-7629

Overall goal of my program is

To develop multiple disease resistant

groundnut cultivars

Specific goal is,

To transfer multiple disease resistances

available in diploid wild species into

susceptible cultivars

Outline

• Genomes and species relationships in

genus Arachis

• Challenges to producing Arachis

interspecific hybrids and germplasm

introgression

• Greenhouse and Field evaluations of

interspecific hybrid derived breeding

lines

• Ideas for Cassava improvement

Genomes and species relationships

in genus Arachis

Genus Arachis has nine sections and A. hypogaea

belongs to section Arachis

Section Arachis has diploid (2n=2x=20),

tetraploid (2n=4x=40) and aneuploid (2n=2x=18)

species

Species in section Arachis cross relatively

easily with A. hypogaea resulting in hybrid pegs/

seeds

Potential disease resistant species are diploid

and crossability with A. hypogaea varies from

0-5%

• A. hypogaea is an allotetraploid with two

different genomes (A and B) in it‟s make

up

• „A‟ genome is characterized by a small

chromosome pair and „B‟ genome which

lacks the small pair of chromosomes

A genome B genome

Challenges to producing Arachis interspecific

hybrids and germplasm introgression

Critical issues in interspecific hybridization are

1) How to improve the efficiency of hybrid

production/development? (Incorporation)

2) How to induce/improve the efficiency of

recombination between parental chromosomes?

(Introgression)

Pathways of Germplasm Introgression

• Triploid-Hexaploid Route

• Tetraploid Route

• Autotetraploid

• Amphidiploid

Cultivated Peanut Wild Species

2n = 4x = 40 (Tetraploid) 2n = 2x = 20 (Diploid)

A A B B A A

A A B

A A A A B B

Hexaploid hybrid

2n = 6x = 60

Sterile Triploid F1 hybrid

2n = 3x = 30

AABB AABB

Colchicine treatment

self 10 or more generations

Tetraploid Introgression Lines

10 10 10 10 10 10

10 10 10

10 10 10 10 10 10

x

2n=4x=40 2n=2x=20

2n=3x=30 2n=6x=60

0.2% Colchicine for 6-8 h

Tetraploid Route

Species A Species A x Species B

(2x) (2x) (2x)

F1 hybrid (2x)

Colchicine Colchicine

Autotetraploid x A. hypogaea x Amphidiploid

(4x) (4x) (4x)

4x 4x

Greenhouse and Field evaluations of

interspecific hybrid derived breeding lines

Most common groundnut diseases in NC are

Early leaf spot Late leaf spot Web blotch

CBR Sclerotinia TSWV

Species Resistance

A. cardenasii Leaf spots, CBR, Sclerotinia blight

(10017) TSWV, nematodes, several insects

A. diogoi Leaf spots, rust, TSWV, insects

(10602)

A. correntina TSWV and Sclerotinia blight

(9530, 19616)

A. duranensis Aflatoxin

(30060, 30064, 30073)

Early Leaf Spot Evaluations

at Lewiston (2005-08)

26 Tetraploid (2n = 4x = 40)

interspecific hybrid derived

breeding lines

11 Commercially grown susceptible

Virginia-type cultivar checks

7 Resistant A. hypogaea checks

Lines were evaluated independently in

side-by-side spray-controlled and

unsprayed field tests for early leaf spot

Estimates of defoliation percentage and

visual ratings were made on a plot basis

with 1 = no disease to 9 = dead plants

Plot yield was measured by weighing all

pods harvested and yield estimates were

made

Unsprayed leaf spot test (2005-08)

3107

3034

3026

2974

2939

2830

2818

2790

2789

2736

2710

2642

2559

2547

2487

2479

2442

2298

2267

2249

2239

2207

2139

2063

2044

1992

1831

2185

245425

37

2890

3335

1883

1897

2181

2213

223023

032387

241025

30261826

86

5.20

5.84

4.57

4.48

4.47

4.52 4.65

5.95

5.18

5.20

4.78

4.54

5.69

5.36

5.14

4.39

4.20

6.16

4.48

5.19

4.07

6.26 6.37 6.

66

6.04

5.22

6.48

6.26

6.31

6.22

6.99 7.

18

6.52 6.

79 7.04

7.05

7.06

4.60

2.95 3.

16

4.75 4.88

4.45

0

500

1000

1500

2000

2500

3000

3500

SP

T 0

4-05

HT

S 0

2-03

HT

S 0

2-01

SP

T 0

4-06

HT

S 0

2-10

SP

T 0

4-08

HT

S 0

2-06

HT

S 0

2-07

SP

T 0

4-07

SP

T 0

4-03

HT

S 0

2-04

HT

S 0

2-02

SP

T 0

4-10

SP

T 0

4-02

SP

T 0

4-04

SP

T 0

4-01

HT

S 0

2-08

SP

T 0

4-09

SP

T 0

4-12

HT

S 0

2-09

HT

S 0

0-02

SP

T 0

4-14

SP

T 0

4-13

HT

S 0

3-01

SP

T 0

4-11

HT

S 0

2-05

Bra

ntle

yP

hilli

psN

C 1

2CP

erry

Gre

gory

NC

-V 1

1N

C 7

Wils

onV

A-C

92R

NC

6V

A 9

8RG

P-N

C 3

43P

I 269

685

PI 1

2106

7K

anyo

ma

PI 2

7080

6P

I 109

839

Line

Po

d Y

ield

(lb

/A)

0

2

4

6

8

10

12

14

16

Def

ol.

sco

re

Grade characteristics of cultivars and selected breeding lines

derived from interspecific hybrids

Cultivar/

Line

Avg.

pod

Bright-

ness

(Hunter L)

Meat

(%)

Pod

Yield

(lb/A)

NC 12C 80.2 74.4 44.9 37.0 68.0 71.2 2530

NC-V11 76.3 70.7 44.5 23.5 67.6 70.8 2303

Gregory 87.6 83.1 44.3 41.5 67.2 70.5 2387

Perry 87.5 86.9 42.9 32.9 66.4 69.6 2410

VA 98R 79.2 73.0 44.4 25.4 65.4 70.0 1883

HTS 02-01 81.4 84.3 42.6 31.7 66.4 68.9 3026

HTS 02-02 74.7 79.9 43.2 26.2 60.9 64.7 2642

SPT 04-06 77.9 91.4 43.5 36.5 67.5 70.5 2974

SPT 04-05 71.1 55.3 44.3 27.1 66.3 68.7 3107

Flavor profiles of 16 different ELS resistant

interspecific hybrid breeding lines along with the

industry flavor standard, NC 7, were analyzed

None of the breeding lines were significantly

different from NC 7 in flavor quality

CBR Sclerotinia

TSWV

Disease inoculations

AUDPC for Sclerotinia and CBR root rot

scores of selected cultivars and

interspecific breeding lines

CBR

Line AUDPC Score*

Gregory 92.8 20.5 3.64 ±0.34

Perry 94.7 ±20.5 3.57 ±0.34

N96076L 57.6 ±17.7 4.06 ±0.28

SPT 06-07 6.4 ±35.8 3.62 ±0.48

HTS 02-01 67.8 ±38.8 3.39 ±0.48

SPT 06-03 82.9 ±35.8 3.22 ±0.48

SPT 04-06 48.5 ±35.8 3.05 ±0.48

*0 = Clean root 5 = Completely rotted root

TSWV Evaluations (2005-07)

110 plots from A. hypogaea x A. cardenasii

were evaluated for TSWV resistance in

field tests at Lewiston, NC

Dead/diseased plants were counted in

plots every 2-weeks beginning in early

June until 2 weeks before harvest

22 whole plots were selected for field

resistance to TSWV

Yield and Disease Evaluations of Interspecific Hybrid Derived

Breeding lines and Cultivars at PBRS, Lewiston, NC, 2005-08

ID Defol. Score Pod Yield W/out CBR SB TSWV

(1=none to 9=complete) leaf spot control (lb/A)

Brantley 6.4 2742 - S -

Champs 5.8 3244 C - -

Gregory 6.4 2493 - - -

Perry 6.3 2497 - - -

Phillips 6.4 2551 - - -

VA 98R 7.0 2277 - S -

Wilson 6.5 2786 - - -

HTS 00-02 4.1 2673 - - T

HTS 02-01 4,3 3449 C S -

HTS 02-02 4.3 3226 - S -

HTS 02-03 5.6 3077 - - -

HTS 02-04 4.7 2933 - - -

HTS 02-05 5.0 2274 - - -

HTS 02-06 4.3 3376 - - -

HTS 02-07 5.9 3017 - - -

HTS 02-08 4.0 2724 C S -

HTS 02-09 4.8 2624 C S -

HTS 02-10 4.3 3103 - - -

HTS 03-01 5.3 2910 - - -

SPT 04-01 4.0 2678 - - -

SPT 04-02 4.8 2971 - - -

SPT 04-03 4.7 3242 - - -

SPT 04-04 4.5 2967 - - -

SPT 04-05 4.4 3145 C S -

SPT 04-06 4.3 3114 - - -

SPT 04-07 4.9 3156 C S -

SPT 04-08 4.3 3138 - - -

SPT 04-09 5.4 2951 - - -

SPT 04-10 5.5 2983 - - -

SPT 04-11 5.5 3134 - - -

SPT 04-12 4.2 2276 C S -

SPT 04-13 5.8 2742 - - -

SPT 04-14 5.7 2311 - - -

SPT 06-01 4.0 3396 - - -

SPT 06-02 4.2 2276 - - -

SPT 06-03 4.6 3264 - S T

SPT 06-04 3.5 2777 C S -

SPT 06-05 4.3 1983 - - -

SPT 06-06 3.1 2861 C S T

SPT 06-07 3.0 2986 C S T

SPT 06-08 4.2 3550 - - T

SPT 06-09 4.5 2773 - - -

SPT 06-10 4.5 2859 - - -

AYT at Lewiston, NC, 2007-08

ID Pod Yield (lb/ac)

GG/WS15 3033

GG/WS15 2624

SPT 06-06 3380

DL1/C99R/WS12 3713

SPT 06-01 3827

HTS 02-01 4091

SPT 04-02 4001

NC-V11/01LSP14 4409

NC12C/WS15 4908

Perry/WS12 3494

Perry/WS12 3464

VA98R/00BLSS12/Chico/00BLSS12 4243

VA98R/01LSP14 3955

VA98R/01LSP14 4258

SPT 06-07 4258

SPT 04-05 3713

UF97318//UF97318/NC343 3592

SPT 04-06 4916

Gregory (Check) 2397

Phillips (Check) 4379

Overall Conclusions

Successfully transferred multiple disease

resistance

Yield and grade characteristics were competitive

Selected set of breeding lines will be evaluated in

PVQE in 2009

Promising lines will be evaluated in multi-state

(VA, NC and SC) trials in 2010 before considered

for release

Ideas for Cassava Improvement

Steps in Cassava germplasm enhancement pipeline

Acquire Evaluate Transfer Deploy

Marker Assisted Selection

Field breeding and evaluations

Courtesy of Dr. Kuraparthy

Traits of concern for Cassava breeding

1. Susceptibility to diseases

2. Highly heterozygous

3. Vegetative propagation

4. Variable flowering patterns

5. Low seed set and seed dormancy

6. Lack of genetic studies about inheritance of

useful traits (HCN levels in Manihot species?)

Hybrid Seed Production and Inbreeding

Concerns

Gene segregation from favored heterozygotes to

unfit homozygotes

Too drastic that the inbreds may not survive

Developing inbreds by successive selfing takes

> 10 y

Solution: Doubled Haploids?

Inbred vigor can be improved by a few recurrent

selection cycles (Sibbing elite clones to S2 and

recombining the surviving progenies) as

suggested by

Tallury, S. P. and Goodman, M. M. (2001) in

“Broadening the genetic base of crop plants”

CAB publication

Short term goals (1-3 years)

• Continue evaluation of existing

materials and explore possibilities for

hybrid seed production

• Evaluate Manihot species for disease

resistance and other traits

Greenhouse inoculations

Molecular markers using BSA

• Characterize species genomes by

Crossability

Karyotyping and

DNA fingerprinting

• Initiate interspecific crosses to broaden

the germplasm base

Long term goals (3-5 years)

Specifically, I would

• Attempt to produce a large # of

triploid hybrids

• Also, produce amphidiploids to use

in bridge crosses

• Greenhouse/lab and field evaluations

for inbred line development and

hybrid production

Vision for Cassava Research

Cassava Improvement

Evaluate

germplasm

Develop superior

germplasmDistribute

germplasm

Fingerprinting

Genetic Mapping

Sequencing of genes

Training

Genetic Diversity

Molecular

Breeding

Cooperators