Purple blotch disease of Allium spp. crops caused by Alternaria porri has remained a major concern in agriculture for both farmers and research fraternity as it severely damages the crops and drastically reduces the yield. The symptoms appear after 1–4 days of infection and bulb rot begin, and eventually turn into dark reddish-purple and then brownish/black lesions. Many factors like season, time of sowing, humidity and temperature, stage of crop, and plant architecture have a huge impact on the progression of purple blotch disease. Many genic markers based on amplification of an Alta1 gene sequence have been designed for identification and differentiation of different Alternaria species groups. Among the most commonly used fungicides, mancozeb, tebuconazole, difenaconazole and azoxystrobin were found to be the ideal for the management of purple blotch disease and increased garlic yield. Many biological approaches such as plant extracts and bio-control agents were found partially effective for controlling the disease. A report on QTL mapping for purple blotch resistance discovered that purple blotch resistance is controlled by a single dominant gene ApR1. To completely understand the purple blotch disease resistance for crop improvement, a study is required at transcriptome level for hunting purple blotch resistant genes by gene annotation and mining. Genetic engineering and genome editing are other approaches that can be done for engineering disease resistance in Allium crops for genetic improvement.

葱属紫斑病。交替链球菌引起的农作物一直是农业和农民研究领域的主要关注问题，因为它严重损害了农作物并大大降低了产量。感染1–4天后出现症状，开始出现鳞茎腐烂，最终变成深红紫色，然后变成棕褐色/黑色病变。诸如季节，播种时间，湿度和温度，农作物生长期以及植物结构等许多因素对紫斑病的进展有巨大影响。已经设计了许多基于Alta1基因序列扩增的基因标记来鉴定和区分不同的链格孢菌物种组。在最常用的杀菌剂中，已发现曼哥西布，戊唑醇，苯达康唑和嘧菌酯是处理紫色斑点病和增加大蒜产量的理想选择。人们发现许多生物方法，例如植物提取物和生物控制剂，对控制这种疾病部分有效。关于紫斑病抗性的QTL作图的报告发现，紫斑病抗性由单个显性基因ApR1控制。为了完全了解紫色斑点病对作物改良的抗性，需要在转录组水平上通过基因注释和挖掘来寻找紫色斑点抗性基因的研究。基因工程和基因组编辑是可用于在葱属中进行工程抗病性的其他方法 农作物用于遗传改良。