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Carolina Uquillas, Eduardo Torres, Antonio Ibacache, and Bruno G. Defilippi

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Luis Humberto Escobar Torres, Eduardo Alejandro Olate Muñoz, Miguel Jordan, and Marlene Gebauer

Callus induction (CI) and later shoot induction (SI) were studied in Leucocoryne purpurea, a native and endemic Chilean geophyte species. Basal leaf portions (BL), bulb basal plate (BP), and root tips (RT) from in vitro plants were used as explants. Treatments for CI included all three explants and media containing different sources and concentrations of auxins and cytokinins as plant growth regulators (PGRs). Plant material was initiated on MS basal medium (Murashige and Skoog, 1962), supplemented with vitamins, 30 g·L-1 sucrose, 6.0 g·L-1 agar and pH adjusted to 5.7 before autoclaving. The experiments were carried on a growth chamber at 24 ± 1.5 °C. CI cultures were maintained in darkness for 16 weeks, and SI for 12 weeks in a 16-hour photoperiod. BL and RT explants did not respond to any of the CI treatments. BP explants cultured on MS basal medium without PGRs also did not produce any callus. The average frequency of callus induction for BP was 78% and the average fresh weight of callus was 10.06 g/explant after 16 weeks of culture. Best treatment for CI was BP cultured on 4.52 μm 2,4-dichlorophenoxyacetic acid (2,4-D) in combination with 0.45 μm 6-benzyladenine (BA), when they were compared to 2,4-D alone or picloram as auxin source. After 16 weeks of culture, calli were transferred to SI medium, supplemented with three different concentrations of thidiazuron (TDZ), either intact or subdivided (150 mg/explant). SI treatments had a greater and significant response when the callus came from a CI medium containing auxin and cytokinin combined, in comparison to those coming from a CI medium containing auxins only.

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Adriano dos Santos, Francisco Eduardo Torres, Erina Vitório Rodrigues, Ariane de Andréa Pantaleão, Larissa Pereira Ribeiro Teodoro, Leonardo Lopes Bhering, and Paulo Eduardo Teodoro

This study aimed to evaluate the adaptability and phenotypic stability of cowpea genotypes using a nonlinear regression analysis and multivariate analysis. Experiments were performed at four sites in Brazil using a randomized blocks design with 20 treatments and four replications. The adaptability and stability of genotypes were evaluated by Toler nonlinear regression and genotype plus genotype × environment (GGE) biplot methodologies. Most of the genotypes revealed linear response patterns, with no differences regarding the favorable and unfavorable environments. Regarding the genotype classification for stability and adaptability, the Toler and GGE biplot methodologies are congruent. Genotypes MNC99-537F-4, MNC00-561G-6, MNC99542F-5, and Patativa have high overall adaptability and adequate yield. Therefore, they should be recommended for cultivation in the tested environments. Genotypes closer to the ideotype by the GGE biplot method are considered doubly desirable by the nonlinear method.