배나무잎검은점병 무독수의 선발 및 품종 저항성

Selection of Pear Trees Free from Pear Black Leaf Spot Disease and Resistant Test for Pear Tree Cultivars

배나무잎검은점병에 대한 종합방제 대책을 수립하고자 시험을 수행하였다. 배 생산단지로부터 무독모수를 선발하기 위해서 본 병에 대한 감염 여부를 검정한 결과, 배나무잎검은점병이 발생하지 않는 6주를 확인하였다. 본 바이러스는 $40/32^{\circ}C$에서 3주간, $37/30^{\circ}C$에서 4주간 변온처리에 의해서 무독화가 가능하였으나 신초의 활착률이 매우 낮았다. 본 바이러스를 접종하여 병징이 발현하는 품종은 신고 등 7품종이었고, 발현하지 않는 품종은 수황배등 11종이었다. 품질이 우수한 저항성 품종인 수황배를 배나무잎검은점병이 발생하고 있는 신고 배나무에 고접한 결과 배나무잎검은점병이 전혀 발생하지 않았다.

This study was conducted to investigate the integrated control strategy against pear black leaf spot disease. Using indicator plant PS-95 we selected six virus-free trees (cv. Niitaka) from commercial orchards in the major pear production area. Disease symptom by pear black leaf spot in the shoot of pear (Niitaka) has been successfully inhibited by heat treatments for 3 weeks at temperature of $40^{\circ}C$ (day) and $32^{\circ}C$ (night) or 4 weeks at $37^{\circ}C$ and $30^{\circ}C$, respectively. However, survival rate of the shoot tips on stocks was low. Seven cultivars Niitaka, Imamura- aki, Waseaka, Nijisseiki, Wasenijisseiki, Shinsetsu and Whangkeumbae produced visible symptoms in the first year after inoculation with the virus. Other 11 selections remained symptomless. Two resistant cultivars Suwhangbae and Gamcheonbae were selected, which showed high fruit quality. It is recommended that these cultivars could be top-grafted onto the infected Niitaka trees to overcome the damage caused by the disease in the orchard.