Certified seed producers systematically select and propagate registered varieties year after year in order to maintain their uniformity and the original registered cultivar traits. However, natural mutations, spontaneous breeding between varieties and alien grain contamination can introduce undesirable variability. NRVC 980385 is a temperate japonica rice cultivar (Oryza sativa ssp. japonica) first registered in Spain in 2002. In 2005 certification tests detected a plot differing from the original traits in terms of uniformity and height suggesting the presence of a certain heterozygosis. This material was therefore seen as an opportunity to obtain newly stabilized doubled haploid (DH) lines which could compete in the Spanish short grain seed market. In this study, an in vitro anther culture protocol is defined which also covers the field tests selection to obtain four new, improved and stabilized DH derived lines ready to be registered for commercial proposes. This took just four years from the initial anther collection until new lines were grown in large scale field trials. Consequently, this protocol reduces the time for obtaining field assessed DH lines thereby having considerable advantages over other techniques by both maintaining the original registered cultivars and/or generating new derived varieties.

<p>El maíz es un producto importante en la Altillanura colombiana por su gran potencial económico en la agroindustria de alimentos concentrados para animales. No obstante, el cultivo se ve afectado por insectos plaga entre los que cuenta la Chinche café, <em>Euschistus rufimanus </em>(Stall) (Hemiptera : Pentatomidae), insecto que provoca deformación y disminución del área foliar de las hojas jóvenes, pérdida de la dominancia apical, macollamiento, esterilidad y muerte de la planta. El presente estudió determinó el ciclo biológico de <em>E</em>. <em>rufimanus </em>bajo condiciones de casa malla, temperatura de 28°C ± 2°C y humedad constante del 75%. A tal fin se colectó una población de adultos de la Chinche en un cultivo comercial de la Altillanura y se estableció una colonia. La duración de huevo a adulto fue de 43,5 días. La duración promedio de los estadios en días fue: huevo (4,88 ± 0,1); ninfa de primer instar (3,6 ± 0,1); ninfa de segundo instar (8,5 ± 0,5); ninfa de tercer instar (8,17± 0,5); ninfa de cuarto instar 7,70 ± 0,54; ninfa de quinto instar 10,5 ± 0,6, siendo el segundo el de mayor mortalidad (60,68%). La longevidad promedio fue de 74,5 ± 4,8 días para los machos y 77,5 ± 5,6 para las hembras. La duración promedio de la fase de preoviposición fue 8,32 ± 1,18 días y la de precópula fue 7,6 ± 1,1 días. El número promedio de posturas por hembra fue de 32,24 y el promedio de huevos por postura de 77,1 ± 10,8. Estos conocimientos servirán de fundamento para el desarrollo de estrategias de manejo integrado de plagas. </p><p> </p><p><strong>Life cycle of </strong><em>Euchistus rufimanus </em><strong>(Stall) (Hemiptera : Pentatomidae) a corn pest in the eastern plains of Colombia </strong></p><p>Maize is an important crop in the well drained savannas in the Colombian eastern planes (known as ‘Llanos Orientales’) because of its economical potential in the balanced feed industry for livestock. However, insects like the brown stinkbug, <em>Euschistus rufimanus </em>(Hemiptera : Pentatomidae), is among the entomological problems that can seriously affect this crop. It causes malformation and decrease of leaf area index on young leaves, loss of apical dominance, sterility and death. This study established the insect life cycle under greenhouse conditions. Study temperature and relative humidity conditions were 28°C ± 2°C and 75% RH, respectively. Bugs were collected from cornfields and reared under controlled conditions to determine egg to adult development. The life cycle was as follows: the egg to adult period was 43.51 days; eggs 4.88 ± 0.14 days; nymphs undergo five instars: instar I 3.64 ± 0.07 days, instar II, 8.53 ± 0.50 days; instar III, 8.17 ± 0.51 days; instar IV, 7.70 ± 0.54 days, and instar V 10.57 ± 0.63 days. Nymphs of instar II had the highest mortality rate (60.68%). Average male longevity lasted 74.52 ±4.87 days and 77.5 ± 5.65 days for females. Pre-copulation period was 7.66 ± 1.17 days, and pre-oviposition lasted 8.32 ± 1.18 days; The female bug laid on the average 32.24 nests, with a mean of 77.12 ± 10.87 eggs. This information is very important to determine pest integrated management strategies against <em>E. rufimanus</em>. </p>