Induction of flowering in Cassava (Manihot esculenta Crantz)

La floración en yuca (Manihot esculenta Crantz) está estrechamente relacionada con la ramificación. Aunque los agricultores prefieren los genotipos de tipo erecto, su utilidad como progenitores está limitada por su baja o nula producción de semillas. El objetivo de este estudio fue evaluar el efecto de la extensión del fotoperíodo de luz roja, la poda y la aplicación de benciladenina para inducir la floración en los genotipos de yuca GM 971-2 (ramificado, floración intermedia), CM 4919-2 (erecto, floración tardía), y SM 3348-29 y GM 3893-65 (erecto, tardío o sin floración). Los genotipos fueron cultivados en un experimento factorial en condiciones de fotoperiodo normal (FN) y de fotoperíodo extendido (FE). Además, las ramas jóvenes del primer y segundo eventos de ramificación (ER1 y ER2) se podaron y rociaron con benciladenina (BA). Las plantas sin poda y sin aplicación BA sirvieron como controles. En FE, el tiempo para generar un ER disminuyó para GM 971-2. Además, CM 4919-1, SM 3348-29 y GM 3893-65 produjeron de uno a varios ER en FE pero no en FN. La poda de las ramas jóvenes en ER1 y ER2 fortaleció la dominancia apical de la inflorescencia, aunque la baja frecuencia de flores femeninas por inflorescencia limitó la producción de semillas. El tratamiento con benciladenina aumentó el número de flores femeninas, por lo tanto, aumentó la producción de frutas y semillas. En comparación con los controles, el uso combinado de FE, poda y BA aumentó significativamente la producción promedio de semillas de 10 a 27, de 0 a 22 y de 0 a 60 semillas para GM 971-2, CM 4919-1 y SM 3348-29, respectivamente.Flowering in cassava (Manihot esculenta Crantz) is closely linked to branching. Although farmers prefer erect-type genotypes, their usefulness as parents in breeding is limited by their low or no seed production. The objective of this study was to evaluate the effect of red light photoperiod extension, pruning and the application of benzyladenine to induce flowering in cassava genotypes GM 971-2 (branched, intermediate flowering), CM 4919-2 (erect, late flowering), and SM 3348-29 and GM 3893-65 (erect, late or non-flowering). The genotypes were cultivated in a factorial experiment under normal (FN) or extended photoperiod (FE) conditions. In addition, young branches from the first and second branching events (ER1 and ER2) were pruned and sprayed with benzyladenine (BA). Plants without pruning or BA application served as controls. In FE, the time to generate an ER decreased for genotype GM 971-2. Moreover, genotypes CM 4919-1, SM 3348-29 and GM 3893-65 produced from one to several ERs in FE but not in FN. The pruning of young branches in ER1 and ER2 strengthened the apical dominance of the inflorescence, although the low frequency of female flowers per inflorescence limited the production of seeds. Benzyladenin treatment increased the number of female flowers, therefore, increasing the production of fruits and seeds. In comparison to controls, the combined use of FE, pruning and BA significantly increased the averaged seed production from 10 to 27, 0 to 22 and 0 to 60 seeds for GM 971-2, CM 4919-1 and SM 3348-29, respectively.Centro Internacional de Agricultura Tropical (CIAT)Next Gen: Flowering Induction on cassavaMaestrí

Reproductive biology of cassava = Biología reproductiva de la yuca

This 9-minute video presents images of cassava flowering and its close association with branching. Changes in the shape of the apical meristem before emergence of flowers, female and male flowers and pollination techniques are described in detail. Este video de 9 minutos muestra los eventos más relevantes en la floración de la yuca/mandioca y su asociación con la ramificación. Se muestran los cambios en la forma del ápice de crecimiento previos a la emergencia de inflorescencias, las flores femeninas y masculinas y el protocolo para realizar cruzamientos dirigidos

Protocol and analysis of in vivo pollen tuve growth = Protocolo y análisis del crecimiento in vivo del tubo polínico en yuca/mandioca

This 9-minute video describes the protocol used in cassava for the analysis pollen tube grow in vivo. Then images of pollen tube growth taken with a fluorescence microscope are presented to illustrate the process. Finally an overall description of the time required for the pollen tube tip to reach the embryo sac is presented. Este video de 9 minutos describe el protocolo usado en yuca/mandioca para el análisis del crecimiento del tubo polínico in vivo. Luego se presentan numerosas fotografías, tomadas en microscopio de fluorescencia, para ilustrar el proceso hasta que el tubo polínico llega al saco embrionario. Finalmente se presenta información de los tiempos requeridos en todo el proceso

Induction of flowering in cassava through grafting

Flowering in cassava is related to branching. Erect plant architecture is usually preferred by farmers but results in late and scarce flowering, which slows down breeding and genetic studies. The objective of this study was to induce earlier and more abundant flowering, which have become key research needs for cassava. Six non- or late-flowering genotypes were selected for grafting on a profuse, early flowering understock. Grafted stems did not branch and flower while attached to the understock. Four cuttings from each grafted stem were taken and planted the following season. Paired-row cuttings from non-grafted stems of the same genotypes were planted as checks. Three phenotypic responses to grafting were found. One genotype failed to branch and flower, independently of the origin of the cuttings. Four genotypes branched but did not produce flowers. However, plants from grafted cuttings tended to branch earlier, particularly after the second branching event. Finally, in one genotype, grafting induced not only earlier branching but also earlier and more abundant production of flowers, fruits and seeds than their counterparts of plants from non-grafted stems. This is the first report of grafting effects on the induction of earlier flowering in cassava. Results indicated a delayed effect of grafting which was genotype-dependent based on materials used in this study. The contrasting responses to grafting may be useful for understanding the effect of plant growth regulators and photoperiod manipulations of ongoing research