Diploides selvagens de bananeira com resistência à sigatoka-negra

Abstract

Black Sigatoka is one of the most important foliar diseases of the banana tree. The control of this disease is based mainly on the use of chemical control, however this practice raises the cost of production and can cause environmental impacts and health. The use of resistant cultivars in turn is more feasible and economically sustainable. The objective of this study was to perform the phenotyping of accessions at Embrapa germplasm collection, aiming at the identification of genotypes resistant to Mycosphaerella fijiensis (Morelet), causal agent of Black-Sigatoka for use in crosses in order to develop improved diploids. The experiment was conducted in the experimental field of Embrapa Mandioca e Fruticultura, in Cruz das Almas city, Bahia, Brazil. We evaluated 31 diploid accesses. The area under the disease progress curve (AACPD), the disease severity index (ID) and the increase in ID (AID) were estimated. The parameter increased disease severity (AID) was efficient in the identification of banana accesses with resistance to black Sigatoka. The selection index for the classification of accesses with moderate resistance to black Sigatoka allows to identify the genotypes with greater quantitative resistance. Five banana diploid accesses were considered resistant to black Sigatoka (Krasan Saichon, Zebrina, Birmanie, Nº 118 and Tuu Gia), while eight were moderately resistant to disease (PA Rayong, Pisang Cici, Malaccensis 2, 028003-01, Microcarpa, Pisang Lidi, Lilin and Malbut).