Reduced Iris Yellow Spot Symptoms through Selection within Onion Breeding Lines

Iris yellow spot (IYS) disease in onion (Allium cepa L.) is caused by thrips (Thrips tabaci vectored virus (IYSV). The absence of cultivars that are resistant/tolerant to and/or IYS a challenge for bulb and seed production worldwide. To measure selection progress reduced/delayed symptom expression breeding lines after two cycles, selections were performed 2011 on previously evaluated exhibited reduced one cycle. Selected plants from each line massed cage the resulted progenies 2013 2014 along with their original populations susceptible check—’Rumba’. In some comparisons, delayed/reduced was observed lines. Plants most selected less than ‘Rumba’. For selections, low severity even relatively high number per plant. These results suggest further improvement might be achievable additional cycles selection.