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BACKGROUND: Garlic is the second largest allium crop after onion and is grown all over the world. The onion maggot (Delia antiqua M.) is a pest that seriously affects the yield and quality of garlic. Cultural controls and insecticides have several potential problems, including pesticide residue and development of resistance. Screening resistant varieties is an ideal alternative method. RESULTS: The resistance of 213 accessions of garlic clones against onion maggot was identified. The results showed that the pest index was between 5.56% and 91.11%, with classification into six groups by cluster analysis: HR (highly resistant), R (resistant), MR (moderately resistant), MS (moderately susceptible), S (susceptible) and HS (highly susceptible). Among these accessions, 9 and 30 were HR and R to onion maggot, respectively. Comparing the resistances of seven pairs of accessions between the original accessions and their progenies showed that single bulb clonal selection could be an effective way to improve allicin content, onion maggot resistance and most morphological traits. The relationship between allicin content and resistance was investigated, and a significant positive relationship was found. Accessions with a high content of allicin have great potential as resistant accessions. CONCLUSION: This study showed significant differences among garlic germplasm in their response to Delia antiqua M. Some accessions were highly resistant and tolerant. Utilization of these accessions will help minimize environmental pollution, preserve agro‐ecosystems and biodiversity, and make management processes more economical. Furthermore, these accessions could be used in breeding programs to develop new maggot‐resistant onion cultivars. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Garlic is one of the most important bulb vegetables and is mainly used as a spice or flavoring agent for foods. It is also cultivated for its medicinal properties, attributable to sulfur compounds, of which allicin is the most important. However, the stability of allicin in garlic extract is not well understood. In this study, using UPLC, the stability of allicin extracted in water from garlic was evaluated in phosphate buffer at different temperatures under light and dark conditions. RESULTS At room temperature, allicin in aqueous extract was most stable at pH 5-6 but degraded quickly at lower or higher pH. It began to degrade within 0.5 h and was not detectable after 2 h when the pH was higher than 11 or lower than 1.5. It degraded quickly when the temperature was higher than 40 °C and especially higher than 70 °C. At room temperature, allicin in water could be stored for 5 days without obvious degradation. Higher concentrations of allicin in solution were somewhat more stable than low concentrations. CONCLUSION Allicin extract was sensitive to pH and temperature of storage but not to light. Higher-concentration allicin solution was more stable. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study was conducted to explore the genetic variation of allicin content among Chinese and Egyptian garlic germplasm, the role of genetic improvement in allicin content enhancement and the combined influence of genetic and environmental factors on allicin contents in Egyptian garlic germplasm grown in Egypt and China respectively. Ultra performance liquid chromatography (UPLC) method was used for quantification of allicin in garlic bulbs. As the result of cluster analysis based on allicin content, all garlic germplasm (104 accessions) were divided into four groups. The germplasms with the highest allicin content presented in group A, comprising only two germplasm (one from Egypt and the other from China). The far distance among accessions in the cluster tree revealed the diversity in the garlic germplasm, which can selectively be used in garlic breeding programs for quality improvement. Clones selected were found to be different from their parents and had higher allicin content, which proves that clone selection is an effective way for garlic genetic improvement. Statistical analysis showed that the effects of germplasm, geographical location and interaction between germplasm and geographical location on the allicin content (P<0.001) in Egyptian garlic germplasm were highly significant. All Egyptian garlic germplasm grown in China had lower allicin content than those grown in Egypt. Allicin content reduction in same germplasms between two locations was 16~63.7%. It is clarified that production area selection for garlic allicin processing industry is important. [ABSTRACT FROM AUTHOR]