Chickpea (Cicer arietinum), as any other legume and most plants for that matter, can be successfully pollinated when the stigma within the flower is ready to receive and retain the fertilizing pollen grains from the anthers of its own or a neighboring flower. Many research papers maintain that pollination in chickpea needs to be carried out before 10 or 11 in the morning on the day the flower blooms. This time period, they claim, is when the stigmas are receptive and the most likely time for cross-pollination to be successful. At ICRISAT, one of the aims of this present investigation was to test the hypothesis that chickpea stigmas were receptive only for a few hours in the morning (till 1100 am) on the day when the flower opened.
The surface of the stigma contains a range of proteins with intense esterase activity involved in the recognition of compatible pollen. Proteinaceous components of the pollen and stigma surface are believed to mediate the recognition process to effect pollination/fertilization. Esterases were taken as the indicator of receptivity of the stigma.
Flowers were emasculated and pollinated on the day the flower opened from 0830 in the morning to 0400 in the evening. All the emasculations and pollinations were carried out under controlled conditions of temperature (30-330C) and relative humidity (48-50%). Happily, we observed that chickpea stigmas were receptive till 0400 in the evening with pollen germination and pod formation from pollinations that were carried out from 0830 to 1600. This was confirmed by stigma surface esterase analysis and pollen germination on the stigma.
Thus, we conclude that under controlled conditions of temperature and a relative humidity, chickpea stigmas retain their receptivity for a longer duration than earlier believed. Hence, manual pollination can be carried out through the day of flower opening and need not be restricted to the morning hours. We hope that this information will facilitate longer working hours for crossing experiments.
For more information contact: N.Mallikarjuna@cgiar.org.