A detached leaf technique was developed for screening peanut genotypes for resistance to leafspot caused by Cercospora arachidicola. Compound leaves offourcultivars of peanut (Arachis hupogaea) and four wild peanut genotypes were used in this study. Individual leaf petioles, each supported by a foam plug, were immersed in Hoagland's solution in 1 x 14 cm test tubes. Leaves were inoculated with C. arachidicola by misting both surfaces with a conidial suspension (2 x 1()4 conidia/ml) using a DeVilbiss atomizer (No. 152). Test tubes with innoculated leaves were placed in racks in a clear polyethylene chamber on a greenhouse bench. Temperatures in the chamber averaged 26 ± 2 C and 31 ± 2 C during night and day, respectively. Relative humidity was maintained between 80 and 90% by hanging wicks ofcheesecloth with their bases in water on both sides of the chamber. Lesions appeared on leaves of susceptible peanuts 8 to 10 days after inoculation and leaflet defoliation started 18 to 21 days after inoculation. This screening technique is reproducible, and requires a minimum of leaf tissue, space, and fungal inoculum.

Green immature leaflets (2-5 mm in length from shoots of germinated seeds or greenhouse grown plants) from species representing seveo taxonomic sections of the genus Arachis (Ambinervosae, Arachis, Caulorhizae, Erectoides, Extranervosae, Rhizomatosae, and Triseminalae), were cultured aseptically, in vitro, on a medium composed of Murashige and Skoog salts, Gamborg's B5 vitamins, 0.8% Difco agar, and supplemented with 1 mg/L each of naphthaleneacetic acid and N-6 benzyladenine. Histological examination of the cultures revealed that the meristematic areas originated from epidermal cells. Embryoids and meristematic shoots developed after lysis of the surrounding cells. All species of Arachis tested produced callus. Genotypic differences for the production of callus, shoots, and roots were observed with cultivated peanuts. Organogenesis occurred in the leaflet cultures, and plants were recovered from sections Arachis and Extranervosae of the genus Arachis.

Abstract— A relationship between Chl a and each of its accessory pigments, neoxanthin, violaxanthin, lutein, Chl b and carotene, is demonstrated in soybean and peanut genotypes. These genotypes include normal and Chl‐deficient types. Plots of Chl a content against accessory pigment content generate straight‐line relationships that are extrapolated to intersect the Chl a axis. The points of intersection correctly predict the order of origin of certain accessory pigments (lutein, carotene and Chl b), but incorrectly predict that neoxanthin and violaxanthin arise after the introduction of Chl a.

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