Screening Musa genotypes for BBTD Aphid in Kou’ou-si

Banana bunchy top disease (BBTD) is a serious threat to banana and plantain (Musa spp.) production. BBTD is caused by the Banana bunchy top virus (BBTV, genus Babuvirus) which is spread through infected plant propagules and banana aphid, Pentalonia nigronervosa. A high level of resistance to BBTD in Musa spp. has not been yet discovered, but there is a wide range of susceptibility among Musa genotypes. In this study, performance of 16 Musa genotypes to BBTD infection was studied during 37 months in two replicated field experiments planted in a BBTD-endemic location in the South region of Cameroon. BBTD expression varied among genotypes without any specific patterns related to their genomic composition. In Abang Minko'o, highest BBTD incidence was observed in Cavendish Williams (100%) and in the plantain hybrid variety PITA 23 (91.6%). A larger group of 11 genotypes including 4 plantain landraces, 3 hybrid plantains, 3 hybrid bananas and a Cavendish Grande Nain were susceptible with incidence between 40 and 80%. The disease incidence was least in Gros Michel and Fougamou which after 37 months had less than 20% symptomatic plants. In Kou'ou-si, 60% BBTD incidence was observed on PITA 23 while two plantain landraces (Asung Mbele, Big Essong) and Gros Michel remained uninfected at 37 months after planting. The banana aphid was present on all genotypes; but excepting PITA 23 and Williams in Abang Minko'o and PITA 14 and PITA 23 in Kou'ou-si, the occurrence of infection was not correlated to aphid abundance. BBTD expression on the same genotype planted in different areas reveals that BBTD expression is not only related to the varietal characteristic but also to the epidemiological situation of the area.

香蕉束顶病（Banana bunchy top disease, BBTD）是威胁芭蕉属（Musa spp.）香蕉与大蕉生产的重大病害。该病害由香蕉束顶病毒（Banana bunchy top virus, BBTV，Babuvirus属）引发，可通过带毒繁殖材料及香蕉交脉蚜（Pentalonia nigronervosa）传播。目前学界尚未在芭蕉属物种中发现对BBTD的高水平抗性，但不同芭蕉基因型间的感病性存在显著差异。本研究于喀麦隆南部香蕉束顶病流行区开展两次重复田间试验，历时37个月，评估了16个芭蕉基因型对BBTD侵染的响应表现。研究发现，不同基因型的BBTD发病特征并无与其基因组组成相关的特定规律。在Abang Minko'o试验点，Cavendish Williams发病率达100%，大蕉杂交品种PITA 23发病率为91.6%，为所有供试材料中最高；另有11个基因型（含4个大蕉地方品种、3个大蕉杂交种、3个香蕉杂交种及1个Cavendish Grande Nain）表现感病，发病率介于40%至80%之间；Gros Michel与Fougamou的发病率最低，种植37个月后显症植株占比不足20%。在Kou'ou-si试验点，PITA 23的发病率为60%；而Asung Mbele、Big Essong两个大蕉地方品种及Gros Michel在种植37个月后未出现显症植株。所有供试基因型上均检出香蕉交脉蚜，但除Abang Minko'o试验点的PITA 23与Williams，以及Kou'ou-si试验点的PITA 14与PITA 23外，BBTD侵染发生情况与蚜虫种群密度并无显著相关性。对同一基因型在不同种植区域的发病表现分析表明，BBTD的发病特征不仅与品种特性相关，还与所在区域的流行病学态势密切相关。