Genetics of new sources of rust resistance, backcrossing in wheat &

overseas testing for stem rust

Harbans Bariana

Genetics – APR to stem rust

Burrion (Sr31+APR)/LB - Two APR genes in Kenya

AWCC993/Yitpi - Monogenic segregation

AWCC1141/Yitpi - Monogenic segregation

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Genetics – APR to leaf rust

Genetic analysis of two landraces showed digenic segregation

Monogenically segregating populations (MSPs) were isolated

Five MSPs are confirmed and genomic location studies are in progress

Two gene segregation was noted in Sonora/BT Schomburgk (BTS) population. One slow rusting minor gene is contributed by Sonora and a major gene is contributed by BTS

Monogenic segregation for an APR gene from Westonia was noted in a cross made for stripe rust resistance analysis

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Genetics –APR to stripe rust

Trigenic segregation in Sonora/BT Schomburgk (BTS) population. Sonora appear to contribute one race-specific and one APR gene. One APR is contributed by BTS

BC1F2 analysis of Wollaroi/2*NYB3 cross confirmed segregation of 3 to 4 genes for adult plant stripe rust resistance

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Genetics –Seedling resistance stripe rust

A new widely effective gene for stripe rust resistance was shown to be linked closely in repulsion with Yr4

Genetic analysis based on Frelon/NYB3 F3 population demonstrated the presence of one more gene in addition to Yr17

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Genetics – Durum wheat

Wollaroi showed infection type 23n to 3n in the seedling stage. This phenotype segregated with Qyr.sun-2A which explains 9 to 12% phenotypic variation. Request to name this locus has been sent to Bob McIntosh. It is likely to be named Yr56.

Identified new sources of resistance against durum leaf rust pathogen, populations are being developed.

An F5 population of a durum genotype carrying APR to stem rust will be phenotypes in 2013

Tamaroi/Bansi F6 population showed monogenic segregation for leaf rust resistance against wheat leaf rust pathogen

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Triple rust resistant donor development through backcrossing

Yr40/Lr57 – Five backgrounds

Lr49,Lr13, Lr34 - four backgrounds

Yr47/Lr52 – Four backgrounds

Yr35/Lr53 – Five backgrounds

Lr67/Yr46/Sr55 – Three backgrounds

Yr49 – Initial crosses made in four backgrounds

Yr37/Lr54 – Initial crosses made

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Amelioration of donors

Sr50 - it was highly susceptible to stripe rust and has been crossed with Yr40/Lr57 and Yr47/Lr52

Yr49 - It was highly susceptible to leaf rust and stem rust. It has been crossed with lines leaf rust and stem rust resistant donors

Yr34 - It is also being improved for leaf rust and stem rust resistance

Sr39 (shortened segment ) has possibly lost leaf rust resistance and it was crossed to top up leaf rust resistance

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Ug99+Sr24 Screening

Bullet, Cadoux, Condor , Clearfield JNZ, Dakota , Gabo, Gamenya, GBA Sapphire, Janz, Kidman, Meering, Mitre, Petrie,, Waagan, – Sr28 type resistance

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Bolac, Crusader, Carinya , EGA Wentworth - Other than Sr28

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Potential threats

› Durum leaf rust races

› Ethiopian and Indian stem rust races

- (Sr13 virulence)

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Response to American leaf rust pathotypes

CA 1.2 09 AZ 103 A THBJBellaroi 3+ ; ;Caparoi 3+ ; ;Gundaroi 3+ ; ;Hyperno 3+ ; -Jandaroi 3+ 3- ;1-Saintly 3+ ; ;Kalka 3+ ; ;Tjilkuri 3+ ; ;WID802 3+ ; ;WID803 3+ 3+ 3+Wollaroi 3+ ;2- ;Yallaroi 3- 3+ 3-Tamaroi 3+ 3+ ;1-Kamilaroi 3- ;1- ;

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Kenya - Ug99+Sr24Genotypes Rust response14 29 35 41 53 614 segB04-17 65Bellaroi 67Caparoi 5,3,2Hyperno 2,45Jandaroi 34Kalka 23,5Saintly 3Tamaroi 5,3Tjilkuri 23,4Wollaroi 5

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Ethiopia - Sr13 virulenceGenotypes Rust response2 516 629 77 85 segArrivato 5 TO 6Bellaroi 67Caparoi 67Gundaroi 7Hyperno 6Jandaroi 5Kalka 67Kamilaroi 7,5Saintly 6Tamaroi 7Tjilkuri 67WID802 67WID803 56Wollaroi 5E, 78LYallaroi 7

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Summary

Focus is to characterize APR genes other than known

Facilitate release of triple rust resistant varieties for growers through provision of resistance donors

National and international training

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Thank You

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IARI RRS, Wellington, India KARI, Njoro, Kenya

PBI, Cobbitty, Australia

98-1,2,3,5,6,.7+34-1,2,7+Sr38

40A – Sr24

Ug99+Sr24