Resumen En el cultivo de amaranto (Amaranthus spp.) Es importante desarrollar nuevas variedades con el ideotipo requerido por los productores, aptas para siembra y cosecha mecanizada, con porte intermedio para que resistan el acame, uniformidad en altura de planta, longitud de inflorescencia, maduración del grano, resistencia a enfermedades y al desgrane, alto potencial de rendimiento y buena calidad del grano. En México, el mejoramiento genético del género Amaranthus está solo basado en selección masal, obteniendo materiales a través del fenotipo y no se ha explotado completamente la diversidad genética del cultivo; por lo anterior, el objetivo del presente estudio fue obtener líneas avanzadas F4 a través de cruzamientos simples para avanzar a una fase superior y contar con líneas promisorias y variedades adecuadas para los productores de amaranto. Con la técnica del cultivo de mini-plantas se realizaron cruzas dirigidas de las que se obtuvieron 6,404 semillas F2, con las que se constituyeron grupos uniformes. En el ciclo primavera-verano PV-2017 se seleccionaron por el método masivo modificado 18 poblaciones segregantes F3, y en el PV-2018 se continuó con el mismo método donde con se obtuvieron ocho poblaciones segregantes F4 con plantas de 1.30 a 1.65 m de altura, aptas para la cosecha mecanizada, panojas compactas, con mayor sincronía en la floración, lo que se tradujo en un mayor peso de grano por panoja (80 %). A través de la mejora de amaranto por recombinación genética es factible la generación de variedades modernas aptas para la cosecha mecanizada, la rentabilidad y sustentabilidad del cultivo.

Summary In the amaranth crop (Amarantus spp.) It is important to develop new varieties with the ideotype required by producers, suitable for mechanized planting and harvesting, with medium plant height to resist lodging, uniformity in plant height, inflorescence length, grain maturation, resistance to diseases and shattering, high yield potential and and good grain quality. In Mexico, the amaranth breeding method is only based on mass selection, obtaining materials through the phenotype, and genetic diversity of the crop has not been fully exploited; therefore, the objective of this study was to obtain advanced F4 lines through single crosses to advance to a higher phase and have promising lines and suitable varieties for amaranth producers. With the mini-plant cultivation technique, direct crosses were made, from which 6,404 seeds in F2 were obtained, and those were used to constitute uniform groups. During the Spring-Summer (SS)-2017 agricultural cycle, 18 segregating F3 populations were selected through the modified bulk method, and in SS-2018 the same method was continued where eight segregating F4 populations were obtained with plants from 1.30 to 1.65 m in height, suitable for mechanized harvesting, compact panicles, with greater synchrony in flowering, which resulted in a higher grain weight per panicle (80%). Through the improvement of amaranth by genetic recombination, the generation of modern varieties suitable for mechanized harvesting, the profitability and sustainability of the crop are feasible.

The soursop Annona muricata is an important fruit for national market, and for exportation, but the crop is affected by pests and diseases. The seed borer wasp Bephratelloides cubensis Ashmead is the pest that produces the highest damage to the crop in Mexico. Sixty percent of damaged fruits and 5-50 seeds per fruit have been registered, with 25% reduction in yield. In Nayarit, Mexico, 100% of damaged fruits were recorded. In this State, an experiment with soursop was conducted to study the life cycle under field conditions and to determine diurnal behavior of the female of B. cubensis. The highest activity of the wasp was observed between 12:00h and 13:00h (35ºC, 54% RH and 409.34 luxes). Females oviposited in fruits with a diameter of 3.1-7.6 cm. Larvae of B. cubensis developed five instars, adults survived no longer than 22 days, and female survived longer than males; they lived 22 and 15 days, respectively. Life cycle of B. cubensis varied from 69 to 122 days.