Mycorrhization and grafting improve growth in the tomato and reduce the population of Nacobbus aberrans

ABSTRACT Inoculation with mycorrhizal fungi and the use of rootstock that is tolerant or resistant to nematodes are two strategies that allow the nematode to be controlled, and plants to coexist with the pathogen. However, the two techniques have always been tested in isolation, when their positive effects are less compared to when they are able to act together. In the present work, two rootstocks combined with the mycorrhizal fungus Rhizophagus intraradices were compared, with the aim of evaluating their behaviour on the growth of tomato plants in soils infested with N. aberrans, the false root-knot nematode. The experiment was set up in a completely randomised design with ten replications, in a 3 x 2 x 2 factorial scheme. The treatments consisted of a combination of three factors: a) plant composition: two rootstocks (Solanum lycopersicum var. cerasiform 'Carolina' and S. lycopersicum 'Maxifort'), onto which the 'Santa Clara' tomato (S. lycopersicum) was grafted, and a non-grafted plant, considered the control, which was the same cultivar as the graft; b) mycorrhization: mycorrhizal or non-mycorrhizal roots; c) a substrate infested or not infested with N. aberrans. The plants grafted onto 'Maxifort' showed significantly greater growth for shoot dry weight, root fresh weight and stem diameter. The rootstock under test had a lower pathogen reproductive factor than did the ungrafted plant. Mycorrhization contributed to a reduction in the number of days until flowering, and a reduction in the final population of N. aberrans for the three plant compositions under test.

摘要 接种菌根真菌以及使用对线虫耐受或抗性的砧木，是两种能够实现线虫防控、使植物与病原物和谐共生的策略。然而此前两类技术始终被单独测试，二者协同发挥作用时的正向效果远优于单独施用时的表现。本研究将两种砧木与根内根孢囊霉（Rhizophagus intraradices）菌根真菌联用开展对比试验，旨在评估其在被异常根腐线虫（N. aberrans，假根结线虫）侵染的土壤中对番茄植株生长的影响。本实验采用3×2×2因子试验方案，以完全随机设计布局，设置10次生物学重复。试验处理涵盖三个因子的组合：a）植株组合：两种砧木分别为樱桃番茄（Solanum lycopersicum var. cerasiform）'Carolina'（'卡罗琳'）与普通番茄（S. lycopersicum）'Maxifort'（'马克西福特'），均以'Santa Clara'（'圣克拉拉'）番茄（S. lycopersicum）作为接穗进行嫁接；另设未嫁接的同品种植株作为对照；b）菌根化处理：接种菌根与未接种菌根；c）基质侵染处理：基质是否被异常根腐线虫侵染。相较于未嫁接植株，嫁接于'Maxifort'（'马克西福特'）的植株，在地上部干重、根系鲜重与茎粗三项指标上均表现出显著更优的生长性能。供试砧木的病原物繁殖因子显著低于未嫁接植株。菌根化处理能够显著缩短开花所需天数，并降低三种供试植株组合下异常根腐线虫的最终种群数量。