Genotypic values and selection gains were estimated in peanut lines derived from backcrossing with synthetic amphidiploid (A. batizocoi x A. duranensis)4x and a commercial cultivar, based on agronomical traits. Thirteen BC1F3 lines were grown in the field and submitted to 21 d of water suppression. Two earliness and drought tolerant cultivars (BR 1 and Senegal 55 437) were used as controls. Eight agronomic traits were adopted to characterize the lines. The estimates were based on mixed models (REML/BLUP) and Sum of Ranks Selection Index. We found that residual variance was greater than genotypic one, indicating the existence of variability within the families. Most traits showed high accuracy values. Three families showed an increased number of pods/plant, pod length and several seeds/pod. Negative gains were achieved for time for blooming and full pod maturation. As these traits are used as criteria for selection for earliness, these results favour the identification of short-cycle plants and prone to tolerate dry environments.

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Essential oils of seven species were investigated in order to control peanut plants against white mold (Sclerotium rolfsii Sacc.). The assays were carried out by in vitro and in vivo assays. At first, fungitoxicity and suppression of oxalic acid diffusion (SOAD) bioassays were performed in order to evaluate the mycelial growth of fungus. Then, validation assays were carried out in greenhouse, involving inoculation of fungus in the seeds and further plant treatments with essential oil. Four isolates of S. rolfsii were tested in different oil concentrations. Cymbopogon martinii oil at 300 ppm inhibited the mycelia growth of S. rolfsii in 55% and also the number of sclerotia. In validation assay, we found that a single dose of C. martinii oil at 400 ppm reduced the rate of disease in 55%, confirming the in vitro assays. The follows traits: number of pods/plant, pod weight and harvest index increased in 57, 54, and 40%, respectively, in all C. martini oil treatments. These results demonstrate that C. martinii oil at low concentration may serve for new formulations in the treatment and prevention of white mold.

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