Overcoming crossing barriers between cassava, Manihot esculenta Crantz and a wild relative, M. pohlii Warwa

Abstract

The use of mentor pollen has enabled successful hybridization between cassava, Manihot esculenta Crantz, and the wild species M. pohlii Warwa. Killed pollen of a cross compatible type produced by freeze-thawing was mixed with incompatible pollen and the mixes were dusted on stigmas. This treatment resulted in production of seed in 4.9% of the total pollinations, compared to 0% in the case of untreated pollinations. The use of a bridge species, M. neusana Nassar, through the hybrid M. pohlii and M. neusana also proved successful in overcoming interspecific barriers between cassava and M. pohlii

Development of cassava periclinal chimera may boost production

“…Nine mature clone plants of 12 months were examined for morphological character-ization based on distinctive characters of habit, leaves, inflorescence, fruits and roots, which distinguish cassava from other wild species (Rogers and Appan, 1973;Nassar et al, 1996).…”

“…The presence of wing on the fruits allows to determine L1 constitution (Tabela 1), because this "diagnostic trait" belongs to cassava (Rogers and Appan 1973;Nassar et al, 1996). Additionally, epidermal traits, such as ordinary cell shape and width, trichomes, and stomatal length and petiole cell width, were used to determine L1 constitution, once they are derived from it (Table 2 and Figure 4) (Satina et al, 1940;Goffreda et al, 1990;Evert, 2007; Marcotrigiano, 2010).…”

“…Improvement programs have concentrated on simple clonal selection and inter-cultivar hybridization (Ceballos et al, 2004;Nassar and Ortiz, 2009). Interspecific hybridization to transfer characters is difficult due to species barriers and the need to break them (Nassar et al, 1996;Rieseberg and Carney, 1998;Ulukan, 2009). Furthermore, the introduction of undesirable characters from the wild form is another drawback, which may need a number of generations and decades to get rid of this undesirable linkage-drag.…”

Incompatibility and Incongruity in Wild and Cultivated Plants

“…The use of mentor pollen to overcome inter-species isolation has been exploited in a number of crop plants and ornamentals, such as black cottonwood (Stettler 1968;Stettler and Guries 1976), poplars (Knox et al 1972;Stettler et al 1980), apples and pears (Visser 1981), Cosmos , Lillium (Vantuyl et al 1982), Cucumis (Stettler and Ager 1984;Pickersgill 1993) and Manihot (Nassar et al 1996). The most significant and reproducible results were obtained in Populus, where high numbers of inter-species hybrids (essentially between P. nigra and P. deltoides) of important agricultural value could be produced.…”

Cassava Genetic Resources: Extinct Everywhere in Brazil

“…The hybrids of cassava with M. glaziovii and M. pseudoglaziovii were very tolerant to drought and exhibited high productivity of tubers (Nassar 1996).…”