Field Guide of Discovery-based Exercises for - Aseanipm ...

Section 7 • Participatory Plant Breeding, Seed Production, Harvest, and Post-Harvest Management
5 Take note of all relevant observations and experiences during this activity.
Pollination of Emasculated String Bean Flowers (Female Parent):
Note: Ideally, flowers should be pollinated immediately after emasculation, although it is
possible to wait until the following morning. In latter case, bagging is necessary after
emasculation to prevent unwanted contamination.
5 Collect freshly opened flowers from selected male parent variety. Place flowers in a paper or
glassine bag, close it and attach a label with name of variety. Store bags with flowers in a cool
shady place in the refrigerator until used. The pollen remains viable for a maximum of 12 hours.
5 To perform pollination, anther sacs must be exposed by removing or slipping backward
innermost petals of mature open flowers. Use hairy-necked style as a brush to rub pollen
grains on green circular stigma.
5 Use one flower to pollinate up to four emasculated buds. Only obliquely arranged discshaped
stigma at tip of style is receptive, not the hairy portion beneath.
5 Affix a small tag listing crossing and date to raceme or peduncle beneath pollinated flower
bud. Do not allow hands, equipment, and other objects to touch receptive portion of stigma
and anther sacs.
5 Upon completion of crossing procedure, cover pollinated flower with a glassine bag to
keep insects out and to minimize risk of contamination. Take care to exclude and remove
crawling and flying insects from plants during and immediately following pollination.
5 Check if each group has completed their exercises and record crosses in crossing table
developed earlier.
5 Take note of all relevant observations and experiences during this activity.
Inspection of Pollinated String Bean Flowers:
Note: Unfertilized flowers may remain attached for 48 hours after anthesis. You can make a
good check on success of a cross three days after anthesis.
5 Observe plants daily until three days after pollination. Note unfertilized flowers to drop-off.
5 After 7-10 days, check for percentage of successfully pollinated flower buds by counting
the number of pods developed per cross as follows:
% Set Seed =
Number of flower buds with pods x 100
Total number of pollinated flower buds
359