Sources of black Sigatoka resistance in wild banana diploids

Abstract

Black Sigatoka (black leaf streak disease) is caused by the fungus Mycosphaerella fijiensisMorelet. This phytopathogen colonizes banana leaves, resulting in reduced photosynthesis and decreased productivity. Fungicide applications are useful to control black Sigatoka; however, they increase production costs and can have adverse environmental and health impacts. The cultivation of resistant cultivars is regarded as a more economically viable option. The objective of this study was to perform diploid phenotyping in a set of wild banana accessions to identify resistant genotypes. A total of 31 accessions (30 with AA genome and one with AB genome) were phenotyped based on the presence of disease symptoms using a scoring scale. The area under the disease progress curve (AUDPC), the disease severity index (DI), and the disease severity increase index (DII) were estimated. The DII variable proved to be efficient in identifying banana accessions with black Sigatoka resistance. Likewise, the selection index for ranking accessions with moderate black Sigatoka resistance allowed us to identify those genotypes with the highest quantitative resistance. Five diploid accessions (Krasan Saichon, Zebrina, Birmanie, Nº 118, and Tuu Gia) were found to be resistant to this fungal disease; eight accessions (PA Rayong, Pisang Cici, Malaccensis 1, 028003- 01, Microcarpa, Pisang Lidi, Lilin, and Malbut) were moderately resistant.

Genetic Improvement for Resistance to Black Sigatoka in Bananas: A Systematic Review

“…118, Tuu Gia, PA Rayong, Pisang Cici, Malaccensis 1, 028003-01, Microcarpa, Pisang Lidi, Pisang Lilin, and Malbut. These have served as parentals for generation of improved diploids for subsequent introgression of genes in new cultivars (Nascimento et al, 2020 ).…”

“…Greenhouse studies corresponded to 24% of the articles, with focus on bioassays for evaluation of gene expression in Musa leaf tissues following inoculation with P. fijiensis . Field studies, which corresponded to only 16% of the articles, mostly focused on agronomic characterization and acceptance of resistant cultivars, with the exception of Barekye et al ( 2011 ), who evaluated the contribution of diploid and tetraploid genotypes to triploid progenies, and Nascimento et al ( 2020 ), who phenotyped 31 diploid accessions of Embrapa's germplasm collection for resistance.…”

“…Nevertheless, we strengthen as our closing remarks, that the banana genetic breeding for black Sigatoka based in the development of resistant cultivars through different methods is an efficient tool in the integrated management of the disease. It is possible, through genetic breeding to obtain basal, quatitative resistance, since complete resistance has not yet been reported for the Musa x P. fijiensis pathosystem due to its complexity, especially as to selection of resistance genes with higher effect, and this is common for most agricultural crops (Kushalappa et al, 2016 ; Pilet-Nayel et al, 2017 ; Nascimento et al, 2020 ). Therefore, decreasing the symptoms of black Sigatoka obtained with limitations in the development of the pathogen in the tissues combined with cultural practices that aim reduction of the inoculum in the cultivated area is the best strategy for mitigating the impacts of the disease.…”

“…118, Tuu Gia, PA Rayong, Pisang Cici, Malaccensis 1, 028003-01, Microcarpa, Pisang Lidi, Pisang Lilin, and Malbut. These have served as parentals for generation of improved diploids for subsequent introgression of genes in new cultivars (Nascimento et al, 2020). Among the cultivars resistant to P. fijiensis mentioned in this review, BRS Maravilha, BRS Platina, FHIA-02, FHIA-18, and Galil 18 have adequate size and high yield potential, and represent alternatives to the traditional Prata subgroup.…”

Improvements in the Resistance of the Banana Species to Fusarium Wilt: A Systematic Review of Methods and Perspectives

“…Another major challenge for the global production of Musaceae species is the development of cultivars resistant to biotic stressors, represented by their primary pests, the banana root borer ( Cosmopolites sordidus ) and the nematodes Meloidogyne spp., Pratylenchus coffeae , and Radopholus similis [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ], and disease-causing pathogens, including banana bunchy top virus (BBTV) [ 20 , 21 ], Xanthomonas vasicola pv. musacearum causing bacterial wilt [ 22 , 23 , 24 , 25 ], Pseudocercospora fijiensis causing black Sigatoka [ 26 , 27 , 28 , 29 ], and Fusarium oxysporum f. sp. cubense (FOC) causing Fusarium wilt [ 30 , 31 , 32 , 33 ].…”