Onion thrips is a major threat to onion crop throughout the world. It is a potential vector of Iris yellow spot virus and causes significant economic damage to bulb production. Phenotypic and biochemical traits of onion cultivars were assessed against Thrips tabaci. Onion Gawran LR-241 (OG) cultivar was tolerant against the infestation of T. tabaci whereas Onion White (OW) was susceptible. Number and size of stomata, cuticle thickness, cell wall thickness and surface wax of onion leaves were studied with the help of scanning electron microscope and quantitative and qualitative analysis was carried out to estimate epicuticular wax and other bio-chemical components through GC/MS. Onion Gawran has thick cell wall, sharp and dense wax crystals, wider central angle and small sized stomata compared to other cultivars. Epicuticular wax components of OG cultivar were heptacosane (5.2%), octacosanol-1 (9.2%), 2-methyl octacosane (4.2%), heptadecanol-1 (5.2%), hexacosanol-1 (4.2%), azulene, 1,4-dimethyl-7-(1-methylethyl) (36.9%), hexadecanoic acid (1.95%), heptadecane (4.2%), triacontanol-1 (5.8%) and hentriacontanone-16 (23.40%). Azulene, 1, 4-dimethy-l-7-(1-methy-l-ethyl) was only found 36.9% in OG but absent in other three cultivars. 2-methyl octacosane was absent in Poona Red Desi and OW cultivars. Hentriacontanone-16, 2-methyl octacosane, fatty alcohols (Octacosanol-1 and Triacontanol-1) and azulene, 1, 4-dimethy-l-7-(1-methy-l-ethyl) were effective in the formation of epicuticular wax in onion cultivars. It implies that phenotypic and biochemical characteristics of OG cultivar proved as resisting features to T. tabaci.

洋葱蓟马是全世界洋葱作物的主要威胁。它是鸢尾黄斑病毒的潜在载体，对球茎生产造成重大经济损失。洋葱栽培品种的表型和生化性状针对烟蓟马进行了评估。Onion Gawran LR-241 (OG) 栽培品种对烟粉虱侵染具有耐受性而洋葱白 (OW) 易感。借助扫描电镜研究洋葱叶片的气孔数量和大小、角质层厚度、细胞壁厚度和表面蜡质，并通过GC/MS进行定量和定性分析，估计表皮蜡质等生化成分。Onion Gawran与其他品种相比，细胞壁厚，蜡晶尖锐致密，中心角更宽，气孔小。OG 栽培品种表皮蜡质成分为庚烷 (5.2%)、二十八烷醇-1 (9.2%)、2-甲基二十八烷 (4.2%)、十七烷醇-1 (5.2%)、六十八烷醇-1 (4.2%)、芘1、 4-二甲基-7-(1-甲基乙基) (36.9%)、十六烷酸 (1.95%)、十七烷 (4.2%)、三十烷醇-1 (5.8%) 和十三烷酮-16 (23.40%)。Azulene, 1, 4-dimethy-l-7-(1-methy-l-ethyl) 仅被发现 36。在 OG 中为 9%，但在其他三个品种中不存在。Poona Red Desi 和 OW 栽培品种中不存在 2-甲基二十八烷。Hetriacontanone-16、2-甲基二十八烷、脂肪醇（Octacosanol-1 和 Triacontanol-1）和 azulene，1, 4-dimethy-l-7-(1-methy-l-ethyl) 可有效形成表皮蜡在洋葱品种中。这意味着 OG 栽培品种的表型和生化特征被证明是抗性特征烟粉虱。