Sensitivity of Seeds to Chemical Mutagens, Detection ofDNA Polymorphisms and Agro-Metrical Traits in M1Generation of Coffee (Coffea arabica L.)

摘要

Coffee (Coffea arabica L.) is threatened by biotic and abiotic stresses. Nevertheless, the breeding of Arabica coffee isrestricted due to its low genetic diversity. Crop improvement via mutagenesis represents an alternative for increasing geneticvariability and facilitating breeding. In this sense, coffee seeds cv. Catuaí were treated for 8 h with a solution of sodium azide(NaN3) (0, 50, 75, 100, and 125 mM) and ethyl methane sulfonate (EMS) (0, 80, 160, 240, 320, and 400 mM). The geneticvariability induced in coffee plants after mutagenic treatment with sodium azide was determined by RAPD and AFLPanalyses. As the concentration of applied NaN3 and EMS increased, the germination, seedling height, and root length decreased.The LD50 values for NaN3 and EMS were between 50-75 mM and 160-240 mM, respectively. For the 12 RAPD primersevaluated, a total of 46 fragments were obtained of which 34 were polymorphic bands (74%). The amplification with sixAFLP selective primer combinations allowed the identification of 36 polymorphisms (17.8%). The analysis revealed that bothNaN3 and EMS induced variability within the DNA regions amplified with AFLP and RAPD markers. Finally, under fieldconditions, significant differences were noticed with respect to plant height, number of nodes in the orthotropic stem, andnumber of branches of the M1 mutant (NaN3-treated) plants compared to the non-mutant plants. Optimal conditions for NaN3and EMS mutagenesis using seeds were determined and the optimized conditions have been used to generate a NaN3 mutantM1 coffee var. Catuaí population.