Resistance to Leaf Spot Disease and Its Correlation with Stomata on Loquat Plants

Under field conditions,168 loquat germplasms were scrutinized for their resistance to leaf spot disease for two years.The disease indices were rated between 3.8and 47.6,with which the germplasms were categorized by a clustering analysis into 5groups.Eight of the 168 germplasms were highly resistant,24 resistant,82 medium resistant,52 susceptible and 2highly susceptible.The 8highly resistant loquats included Mu Luo,Da Mao,Qakleaf,Zhuo Nan 1,Li Zhi,Long Zao 1,Tang Tou 3and Gang Kou 11.The two highly susceptible germplasms were Sen Wei Zao Sheng and Xiang Cheng 4.There was no correlation found between the stomatal density or the size of lower epiderm and the resistance to leaf spot disease of the loquats.