InKenya, Russian wheat aphid (RWA) and stem rust race TTKS (“Ug99”) are the most devastating pests of wheat. Severe infestations by RWA result in yield losses of up to 90% while epidemics of “Ug99”can cause up to ...InKenya, Russian wheat aphid (RWA) and stem rust race TTKS (“Ug99”) are the most devastating pests of wheat. Severe infestations by RWA result in yield losses of up to 90% while epidemics of “Ug99”can cause up to 100% loss. The two pests combined have seriously affected farmer incomes forcing them to rely heavily on pesticides and increasing the cost of production. This study sought to evaluate a wheat line that has been developed to be resistant to both RWA and “Ug99”by pyramiding two major resistance genes. Three varieties were used in this study: “Kwale”, a Kenyan high yielding commercial variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line resistant to RWA but with poor agronomic attributes. The F1 of the double cross (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99”resistance. The surviving DC F1 progenies were left to self pollinate in the field to obtain the DC F2. The DC F2 progenies were sequentially screened against RWA and “Ug99”to obtain a resistant population to both RWA and “Ug99”. The yield and yield components of the new resistant line were compared with the three parents. Results showed that the DC F2:3 had higher yields than the three parents based on 1000 kernel weight, weight of kernel per spike, and the actual yield in tons/ha, indicating that the genes were successfully introgressed. It is concluded that though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99”and can be used as a component for “Ug99”resistance breeding together with other Sr genes.展开更多
Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious ...Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious disease (stem rust race TTKS (“Ug99”)) are currently the biggest problem for wheat producers in Kenya. Severe infestations by RWA may result in yield losses of up to 90% while “Ug99” infected fields may suffer 100% crop loss. The two pests combined are seriously affecting wheat farmers’ incomes because of the heavy reliance on pesticides that increase the cost of production. This study attempted to develop and characterize wheat lines that are resistant to both RWA and “Ug99” by pyramiding two major resistance genes. Three wheat varieties: “Kwale”, a Kenyan high yielding variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line with resistance to RWA but of poor agronomic attributes were used. A double cross F1 (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99” resistance. Surviving DC F1 progenies were left to self pollinate to obtain the F2 of the double cross (DC F2). The DC F2 progenies were sequentially screened against RWA and “Ug99” to yield a population that was resistant to both RWA and “Ug99”. Genotyping of the DC F2:3 families were conducted to select homozygous resistant plants. Data indicated that the RWA and “Ug99” resistance genes were successfully pyramided. Though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99” and can still be effectively used as a component for “Ug99” resistance breeding together with other Sr genes.展开更多
This paper reviewed the research advances of Ug99 and its resistance breeding from the aspects of its discovery, race variation, pathogenicity, distribution, spread, exploration of relative resistant genes, linked mol...This paper reviewed the research advances of Ug99 and its resistance breeding from the aspects of its discovery, race variation, pathogenicity, distribution, spread, exploration of relative resistant genes, linked molecular marker selection and resistance breeding strategies, to provide basis for comprehensive understanding of the new Puccinia graminis f. sp. tritici race Ug99 and its potential threat to wheat production. Ug99 is a new Puccinia grarninis f. sp. tritici race with high variability, strong pathogenicity and rapid spread speed, which is likely to cause global damages to world wheat production. We should strengthen the exploration and utilization of new resistance genes in wheat and relative species and breeding of new wheat varieties with durable resistance, to control and prevent damages caused by Ug99 and its variants.展开更多
文摘InKenya, Russian wheat aphid (RWA) and stem rust race TTKS (“Ug99”) are the most devastating pests of wheat. Severe infestations by RWA result in yield losses of up to 90% while epidemics of “Ug99”can cause up to 100% loss. The two pests combined have seriously affected farmer incomes forcing them to rely heavily on pesticides and increasing the cost of production. This study sought to evaluate a wheat line that has been developed to be resistant to both RWA and “Ug99”by pyramiding two major resistance genes. Three varieties were used in this study: “Kwale”, a Kenyan high yielding commercial variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line resistant to RWA but with poor agronomic attributes. The F1 of the double cross (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99”resistance. The surviving DC F1 progenies were left to self pollinate in the field to obtain the DC F2. The DC F2 progenies were sequentially screened against RWA and “Ug99”to obtain a resistant population to both RWA and “Ug99”. The yield and yield components of the new resistant line were compared with the three parents. Results showed that the DC F2:3 had higher yields than the three parents based on 1000 kernel weight, weight of kernel per spike, and the actual yield in tons/ha, indicating that the genes were successfully introgressed. It is concluded that though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99”and can be used as a component for “Ug99”resistance breeding together with other Sr genes.
文摘Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious disease (stem rust race TTKS (“Ug99”)) are currently the biggest problem for wheat producers in Kenya. Severe infestations by RWA may result in yield losses of up to 90% while “Ug99” infected fields may suffer 100% crop loss. The two pests combined are seriously affecting wheat farmers’ incomes because of the heavy reliance on pesticides that increase the cost of production. This study attempted to develop and characterize wheat lines that are resistant to both RWA and “Ug99” by pyramiding two major resistance genes. Three wheat varieties: “Kwale”, a Kenyan high yielding variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line with resistance to RWA but of poor agronomic attributes were used. A double cross F1 (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99” resistance. Surviving DC F1 progenies were left to self pollinate to obtain the F2 of the double cross (DC F2). The DC F2 progenies were sequentially screened against RWA and “Ug99” to yield a population that was resistant to both RWA and “Ug99”. Genotyping of the DC F2:3 families were conducted to select homozygous resistant plants. Data indicated that the RWA and “Ug99” resistance genes were successfully pyramided. Though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99” and can still be effectively used as a component for “Ug99” resistance breeding together with other Sr genes.
基金Supported by Starting Fund for Introduction of Qualified Personnel from Henan Agricultural University (30300190)~~
文摘This paper reviewed the research advances of Ug99 and its resistance breeding from the aspects of its discovery, race variation, pathogenicity, distribution, spread, exploration of relative resistant genes, linked molecular marker selection and resistance breeding strategies, to provide basis for comprehensive understanding of the new Puccinia graminis f. sp. tritici race Ug99 and its potential threat to wheat production. Ug99 is a new Puccinia grarninis f. sp. tritici race with high variability, strong pathogenicity and rapid spread speed, which is likely to cause global damages to world wheat production. We should strengthen the exploration and utilization of new resistance genes in wheat and relative species and breeding of new wheat varieties with durable resistance, to control and prevent damages caused by Ug99 and its variants.
