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SP11-10
Induction of flowering through grafting of non-flowering
branches on an early flowering rootstock
Calle Fernando 1, Salazar Sandra 1, Bolaños Eugenio 1, Morante Nelson 1, Hershey Clair 1,
and Ceballos Hernán 1*
1) International Center for Tropical Agriculture (CIAT). Palmira, Valle del Cauca. Colombia.
*[email protected], Registrant ID# 3357
Induction of flowering is becoming an important objective to facilitate breeding efforts in
cassava. There is a growing interest and need to breed clones with erect, non-branching
plant architecture because they facilitate mechanization of cultural practices and long stems
can withstand longer storage periods (a key feature for the uncertainties of the arrival of
the rains due to climate change). However, erect types (by default) flower late or may even
fail to flower under normal circumstances. Induction of flowering may also be relevant for
the introduction of inbreeding in the genetic enhancement of cassava. CIAT evaluated the
possibility of grafting non-flowering genotypes on plants serving as rootstock from profuse
and early branching genotypes. The hypothesis is that the hormonal environment of the
rootstock would induce flowering in the grafted branch. To do the graft, one of the
(typically) three branches of the rootstock plant was pruned and grafted with a stem of
similar diameter from a non-flowering genotype. Initial work showed that the grafted
branches failed to flower, perhaps as a result of their relatively limited growth compared
with the remaining untouched branches of the rootstock plants. However, preliminary
results also suggested that if cuttings were taken from the grafted branches and planted the
following season, flowering may be occurring much earlier in the grafted material compared
with non-grafted versions of the same genotype. In June 2015 an experiment was planted to
confirm these preliminary results. Two paired rows were planted with cuttings from grafted
stems in one of them and from non-grafted stems from the same genotype on the other.
Cuttings were planted in the field following the same positon on the stem. In other words,
the first plant was from cuttings taken at the proximal or basal portion of the stem and the
last cutting from the distal or apical portions. Depending on the growth of the branched
stem from 4 to 6 cutting could be obtained and a similar number of cuttings were used for
the row using non-grafted stems of the same genotype. By late September few plants
derived from cuttings of grafted stems had already flowered, but not in plants from the
same genotypes derived from non-grafted stems. Results, therefore, suggest that grafting
can induce flowering but only if cuttings are taken from the grafted branch and planted the
following season.