Towards Orobanche resistance in sunflower - SSR analysis of a novel resistance source

Abstract

Broomrape is an aggressive parasite that penetrates through the roots of the host, absorbs nutrients directly from the vascular system and causes significant reduction in sunflower yield. Genetic resistance proved to be the most efficient method for suppressing severe broomrape attacks in the field; however selection pressure resulted in occurrence of new and more aggressive races of the parasite. Hence, finding new sources of resistance is immensely significant. One of the major focuses of the breeding programs of the Institute for Field and Vegetable Crops, Novi Sad, is finding a source that would provide durable resistance, and introducing this resistance into commercial sunflower hybrids. It was recently observed that line AB—VL-8 was not affected by broomrape attacks in the areas where races F and G were abundant. After repeated field tests it was concluded that the AB— VL-8 is resistant to broomrape races higher than F, and could potentially be used as a new source of resistance. The objective of the present study was to screen and compare the genome of resistant line AB-VL-8 and a susceptible line L-OS-1. The goal was to narrow down the region where the resistance locus is placed, and to get a preliminary idea if the trait is qualitative or quantitative.