Molecular Genetic Variation for Stripe Rust Resistance in Spring Wheat

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a major biotic constraint to global wheat production. Stripe rust can be effectively controlled by developing resistant wheat varieties. This, however, requires identification of resistant sources to be used as parents in breeding programs. Molecular markers provide a quick way of detecting rust resistance genes in adapted wheat material. The present study was conducted to investigate genetic variation for markers linked with stripe rust resistance genes in 67 Pakistani adapted spring wheat varieties using 12 pairs of microsatellite and sequence tagged site markers. Seventy nine percent wheat varieties showed marker allele of Xgwm11 associated with stripe rust resistance gene Yr26, whereas 75% varieties had the Yr26 linked allele of sequence tagged site (STS) marker CYS5. Stripe rust resistance gene Yr5 was found in 45%, whereas Yr9 and Yr10 were present in 28% varieties tested based on the previously reported linked markers. Stripe rust resistance gene Yr17 was found in 10%, whereas Yr18 in 15% of varieties only. Three markers Xwe173, Xbarc181 and Xgwm140 did not produce the expected amplicons associated with the stripe rust resistance genes. Cluster analysis revealed considerable genetic variation for marker alleles linked with stripe rust resistance genes. Results of this study may be useful for wheat breeders in pyramiding stripe rust resistance genes in future wheat varieties of Pakistan through Marker Assisted Selection.

Biophysical Management of Aphid (Schizaphis graminum Rondani) (Hemiptera: Aphididae) in Wheat Crop

“…(Farooq et al, 2008) reported that release of tested predator (C. carnea) significantly reduced aphid population upto (59%) after one week and increased yield upto 4% over control. Our results are in quite agreement with (Iqbal et al, 2008) who showed that tested predator reduced aphid population upto 30.68%.…”

“…Normal cultural practices were performed uniformly in all the treatments. The plots were kept unsprayed throughout the experiment C. carnea egg cards, each containing 100 eggs were slanged at 3cm below the top of wheat tiller during 4 th week of February (Iqbal et al, 2008). Data on the aphid population were recorded 24 hours before and 7, 14, 21, 28 days after installing the egg cards.…”

INTROGRESIÓN DE LOS GENES DE RESISTENCIA A ROYA AMARILLA Yr5a Y Yr15 EN EL CULTIVAR DE TRIGO HARINERO BORLAUG 100

“…Actualmente, aislados virulentos para este gen están ampliamente distribuidos en el mundo (Rodríguez et al, 2009;Sharma-Poudyal et al, 2013;Wellings et al, 2009); no obstante, en México la raza virulenta a Yr17 es avirulenta a Yr27 y Yr31 y muestra virulencia parcial en planta adulta, por lo que Borlaug 100 en planta adulta es moderadamente resistente debido a que los aislados presentes en México son parcialmente virulentos al gen Yr17, además de la presencia de los genes de raza no especifica Yr29 y Yr30, entre otros no identificados. El gen Yr17 aún puede proporcionar resistencia contra varias razas de roya amarilla si se usa en combinación con otros genes (Iqbal et al, 2016), como en el caso del presente estudio donde está en combinación con el Yr5a, Yr15 o ambos.…”