This slide describes major stress like late blight, potato colarado beetle and heat stress in potato and recent breeding advancements in it.

1. Breeding for stress in
potato
-J.Delince

3. Constraints in potato resistance
breeding
• Narrow genetic base.
 European cultivated Solanum tuberosum originated from few specimens introduced in Europe in the
16th century, they show severe inbreeding.
 Introgression of new alleles from wild species
• Multiple ploidy levels in the tuber-bearing Solanum species:
 From diploids (2n=2x=24) to hexaploids (2n=6x=72)
 Incompatibility barriers between different ploidy levels
• Tetraploidy level of the European cultivated potato.
 2n=4x=48 (four pairs of 12 chromosomes)
 Four alleles possibly different for one locus
 High heterozygosity level leading, by crossing two tetra-allelic parents, to a lot of genotypes in the
hybrid progeny
 Genotype x environment interaction
 With traditional breeding, selecting a desirable genotype is a time-consuming process

4. Late blight of potato
• Caused by Phytopthora infestans
• Crop losses due to late blight alone have been estimated as high as
US$210.7 million in the USA, with control costs totaling US$77.1
million for fungicides.
• P. infestans is famous for causing the Irish famine in 1845. Almost 1
million people was died from starvation, malnutrition and disease
and another 1 million was emigrated to avoid the famine in Ireland.

5. Symptoms
• This disease damages leaves, stems and tubers. Affected leaves
appear blistered
• When drying out, leaves turn brown or black in color. When
infections are still active, spots appear on the underside of leaves
• Affected stems begin to blacken from their tips, and eventually
dry out.
• Severe infections cause all foliage to rot, dry out and fall to the
ground, stems to dry out and plants to die.
• Affected tubers display dry brown-colored spots on their skins
and flesh. This disease acts very quickly. If it is not controlled,
infected plants will die within two or three days

6. Life cycle
• They belong to the group called oomycetes
• The asexual cycle of P. infestans begins with the
production of multinucleate sporangia. Sporangia can
germinate either directly through the production of a
germ tube, or indirectly through the production of
zoospores.
• Thus they have high rate of dispersion by asexual
reproduction and high recombination rate through
sexual reproduction(A1 and A2 mating types)
• Favourable temperature is 22 - 24°C with high RH is
conducive for this disease

10. Sources of resistance
Source of Resistance Chromosome number and R-gene
S. avilesi 11 -Rpi-avl1
S. berthaultii 10 Rpi-ber1and Rpi-ber2
S.brachistotrichum 4 Rpi-bst1
S. bulbocastanum 8 (Rpi-blb1 and Rpi-bt1), 6 (Rpi-blb2), and
4 (Rpi-blb3 and Rpi-abpt)
S. capsicibaccatum 11 Rpi-cap1
S. demissum 5 (R1), 4 (R2 and Rpi-dmsf1),
11 (R3-R11 except R8), 9 (R8)
S. hjertingii 4 Rpi-hjt1.1, Rpi-hjt1.2 and Rpi-hjt1.3
S. dulcamara 9 Rpi-dlc1
S. mochiquense 9 Rpi-mcq1
S. papita 8 Rpi-pta1 and Rpi-pta2
S. phureja Rpi-phu1
S. stoloniferum 8 (Rpi-sto1) and 11 (Rpi-sto2)
S. venturii Rpi-vnt1.1,Rpi-vnt1.2 and Rpi-vnt1.3

11. Screening method
• Field and green house screening
• % incidence and Area under disease progressive
curve

12. AUDPC
• For multi-location and multi –seasonal trials
• Kufri, Shillong and Ooty
• Kufri Jyothi is used as susceptible variety

14.  9= no visible infection; 8= 10% infection; 7= 11 to 25%; 6= 26 to 40%; 5= 41 to 60%; 4=
61 to 70%; 3= 71 to 80%; 2= 81 to 90%; 1=> 90%; 0= 100% infection.

16. Variety Resistance
Kufri Himalini Moderately resistant to late blight
Kufri Shailaja Moderately resistant to late blight
Kufri Girdhari Highly resistant to late blight
Kufri Himsona Highly resistant to late blight
Kufri Sutlej Moderately resistant to late blight
Kufri Anand Highly resistant to late blight
Kufri Arun Field resistant to late blight
Kufri Pukhraj Moderately resistant to late blight
Kufri Lalima Moderately resistant to late blight
Kufri Kanchan Field resistant to late blight
Kufri Pushkar Field resistant to late blight
Kufri Badshah Moderately resistant to late blight
Kufri Chipsona- 3 resistant to late blight
Kufri Chipsona- 4 resistant to late blight

17. Insect resistance –Colorado
potato beetle
• CPB is considered as the most important insect
defoliator of potatoes

19. Wild germplasm sources
• S.berthaultii – four lobed trichomes exudate
• S.chacoense – feeding deterrence by leptin I and II
• S.pinnatisectum
• S.tarnii
• S.polyadenium
• S.neocardinesii –glycoalkaloids in leaf

20. Screening
• Field evaluation tests
• Laboratory feeding assays
• The adults and first instar larvae are used for
screening
• 10 First instar larvae for 48 hours
• 27 adults can be used for 8 hours

21. • Colorado potato beetle ('Yukon Gold' (susceptible control), USDA8380- I (leptine
glycoalkaloids), and ML235-4 (glandular trichomes)
• Combination of genetic engineering and natural resistance mechanism

23. Bt varieties
• New leaf – CPB and PLRV
• NewLeaf Y Potato –CPB and PVY
• NewLeaf Plus Potato – CPB and PLRV
• All are from the parent -Russet Burbank Potato

24. Abiotic stress

25. Heat stress
Wild relatives Tolerance
S.Phureja Heat tolerance
S.chacoense Heat tolerance
S.commersoni Heat tolerance
• Critical stage in heat stress is Tuberization and tuber enlargement and stress at
this stage cause Poor tuber growth and yield, splitting, internal brown spot
• Can cause yield loss upto 18 to 32 percent

33. Conclusion
• This study demonstrates that ELA combined with
immunoblot analysis of sHSP accumulation under
HS conditions could be considered as a reliable
procedure in screening potato genotypes for heat
tolerance and for the identification of heat tolerant
potato cultivars.
• In addition, HSP18 and HSP21 expression under HS
present similar patterns in potato plants grown in
vitro compared to exvitro grown plants, opening up
the possibility for the use of an in-vitro culture for
heat tolerance screening

34. Kufri Surya- breeding

37. Abiotic stress resistanceGene Protein expressed Trait conferred
BADH betaine aldehyde
dehydrogenase
Drought tolerance
COD choline oxidase Drought tolerance
T6P Trehalose-6-phosphate Drought tolerance
GG-phosphate phosphatase
synthase
Glucosylglycerol (GG) Drought tolerance
mtlD mannitol-1-
phosphate dehydrogenase
Salinity tolerance
P5CS pyrroline-5-carboxylate
synthetase
Salinity tolerance
HvNHX2 Na+/H+ antiporter Salinity tolerance
Δ12-desaturase Unsaturated fatty acid Cold tolerance
DHAR1 dehydroascorbate reductase Oxidative stress
GalUR d-galacturonic acid reductase Oxidative stress