| The sunflower broomrape is a parasitic plant that parasitizes on the roots of sunflowers.Sunflower plants show dwarf,loss of yield,and dramatic reduction of oil and protein content caused by parasitization.In this study,the Petri dish filter paper system,which was established previously,was used to build up a set of indoor criterion to evaluate the level sunflower resistance to broomrape.In the mean time,two cultivars with significant differences of resistance to broomrape were selected to establish the system of sunflower and broomrape interaction.The results as followed:1.We evaluated the resistance of three sunflower cultivars 5009,JK601 and F917 by using the Petri dish filter paper system.Based on our previous data collected from field,5009,JK601 and F917 were identified as susceptible,resistant and immune,respectively.In this study,the results showed that the germination rate of broomrape seeds has no significant difference on the roots of 5009,JK601 and F917.The number of parasite tubercles was significantly different among 5009,JK601 and F917.Therefore,we recommend to use the number of parasite tubercles as the criterion of sunflower resistance to broomrape.2.The resistant level 12 sunflower varieties were identified by counting parasite tubercles under the standard Petri dish filter paper system.And the results were consistent with the previous data that we collected from the fields,which indicating that the system of Petri dish filter paper combining with counting parasite tubercles can be regarded as a comprehensive evaluating system for sunflower resistance identification.3.The resistant level 80 sunflower varieties to broomrape by utilizing the established criterion under standard indoor condition.The results indicated that 14 sunflower varieties showing immune response to broompare,including 11 oil sunflower linesand 3 edible sunflower lines;Twenty five lineswere identified as highly resistant level,including 14 oil lines and 11 edible lines.Twenty two were identified as moderately resistant level,containing 7 oil lines,and 13 were edible lines.Twelve were identified as susceptible level,consisting of 1 oil line and 11 edible lines.Seven were identified as highly susceptible level and all of them were edible lines.In general,oil sunflowers varieties were more resistant to broomrape comparing to edible varieties.4.Based on the results we have achieved 6 varieties were selected to unravel the mechanism of sunflower resistance to broomrape.The identification of resistant level was repeated and the results were consistent to the first assay.The results indicated that there were extremely significant differences in the number of parasite tubecles on sunflower roots of 6 varieties.Therefore,these 6 varieties can be used for the future study revealing the mechanism of sunflower resistance to broomrape.5.LD 5009,JK601 and F917 were used as the representatives as susceptible,resistant and immune sunflower varieties to confirm sampling methods and time points for initializing the mechanism study of sunflower resistance to broomrape.In the mean time,we optimized the measurement system for resistance related index as well. |
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