Field evaluation of six Gros Michel banana accessions (Musa spp., AAA group) for agronomic performance, resistance to Fusarium wilt race 1 and yellow Sigatoka

Three Gros Michel mutants (‘IBP 5-B’, ‘IBP 5–61’ and ‘IBP 12’) from the Cuban Instituto de Biotecnología de las Plantas, two semi-dwarf Gros Michel varieties (‘Highgate’ and ‘Cocos’) and a Thai accession (‘Hom Thong Mokho’) were evaluated in Australia over a five year period. They were screened for their resistance to Fusarium wilt Race 1 (FocR1) caused by the pathogen Fusarium oxysporum f.sp. cubense, as well as resistance to yellow Sigatoka (Pseudocercospora musae Zimm [teleomorph Mycosphaerella musicola Leach]). They were also grown for a plant and ratoon crop in the tropics (17°S) and a plant crop in the subtropics (28°S) with no disease pressure to record their agronomic characteristics. They were compared with Australian industry standards, ‘Williams’ (AAA, Cavendish subgroup) and ‘Lady Finger’ (AAB, Pome subgroup). In the subtropics the Gros Michel mutants and semi-dwarf accessions were sensitive to cold and very susceptible to FocR1 and yellow Sigatoka while their agronomic performance in the tropics was good, with ‘Highgate’ having the best bunch weight on a shorter, more manageable plant. Of the six accessions evaluated, ‘Hom Thong Mokho’ showed the highest level of resistance to FocR1 although it had poor cold tolerance, as did the other Gros Michel selections, and consequently had low productivity compared to ‘Williams’ and even ‘Lady Finger’. However in the warmer, more humid tropics ‘Hom Thong Mokho's performance was much better and it was less susceptible to yellow Sigatoka than the other Gros Michel selections. Subsequent genetic analysis by Christelová et al. (2011) has revealed that although ‘Hom Thong Mokho’ is marketed as a Gros Michel variety in Asia, it is closer to the Rio subgroup (AAA) of dessert bananas.