✂️ Emasculation and Pollination Techniques

This lesson covers core principles and exam-focused points from this topic in plant breeding.

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Rice ( Oryza sativa ) (2 n = 24) (Family – Poaceae)

In rice anthesis commences shortly after emergence of panicle. Spikelets at the tip bloom

first and proceed downwards. Anthesis time 8-10 am. Each spikelet remain open 30 minutes and

then closes. The anther dehiscence takes place immediately after the opening of the spikelets.

Receptivity remains for one day.

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Emasculation and Crossing techniques

Emasculation is necessarily followed by controlled pollination. Emasculation is done

during early morning between 6 and 8 AM in spikelets, due to open on the same day.

Emasculation should be over well ahead of the time of anthesis. Crossing techniques in rice

differ based on the method of emasculation. Since maximum number of spikelets open on the 3rd

or 4th day of anthesis, panicles of that stage are selected for emasculation. The following

methods are widely used for hybridization in rice.

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Clipping method

In the previous day evening, top 1/3rd and bottom 1/3rd portions in the panicle of the

desired female parent are clipped off by using scissors leaving the middle spikelets. With the

help of scissors again, top 1/3 portion in each spikelet is clipped-off in a slanting position. The

six anthers present in each spikelet are removed wit the help of the needle (Emasculation). Care

must be taken during emasculation for not to damage the gynoecium. Then to prevent

contamination form the foreign pollen, the emasculated spikelets are covered with a butter paper

big. In the next day morning (usually at 9.00AM), the bloomed panicle from the desired male

parent is taken. The top portion of the butter paper bag which was originally inserted in the

emasculated female parent is now cut to expose the panicle. The male parent panicle is inserted

in an inverted position into the butter paper bag and sturned in both ways in order to disperse the

pollen. After ensuring the abundant disbursement of pollen, the opened butter paper bag is closed

using a pin. Coloured thread may be tied at the base of the panicle to identify the crossed ones.

After ensuring pollination, the bag may be removed.

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Hot water method

A method of hot water emasculation is used to about the same extent as the clipping

method. Panicles in 3rd (or) 4th day of blooming are chosen as female parents. An hour or so

before blooming (i.e. normally at 7. A.M.), the panicle is selected and under developed and

opened spikelets are removed. Now, the tiller is bent over (carefully to avoid breaking) and the

selected panicle is immersed in hot water contained in a thermos bottle at 40-440C for a period

of 5 to 10 minutes. This treatment causes the florets to open in a normal manner and avoids

injury. Then, emasculation is done by removing the six stamens by fine forceps or needles and

then dusting should be done.

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Dr. Ramiah method

Panicles on the 3rd or 4th day of its blooming are selected; top and lower splikelets are

removed leaving only the middle. It is covered with a wet cloth and air is blown from mouth.

This facilitates opening of spikelets. After 2-3 minutes, wet cloth is removed and spikelets are

found to be open. Then, the six anthers are removed.

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Vacuum emasculation method

This works on the principle of suction pressure. The spikelets are clipped off prior to

operation. The minute pipette is to be shown at the point of clipping and pollen is sucked in. Six

panicles can be emasculated at a time. By hand emascualtion, 100 flowers can be emasculated

by a person. With the vaccum emasculator, six persons can operate and emasculate 3000 to 3600

florets/hour.

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Cuttack Method

The technique was developed by CRRI, Cuttack. The panicle to be emasculated is

inserted into hallow piece of bamboo closed at one end and plugged with cotton wool and split

cork at the other end. The flowers thus enclosed will open within 5-10 minutes. The anters are

removed.

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Brown paper method

The panicles are enclosed in a Brown paper cover before a couple of hours of blooming.

Heat develops inside due to which the anthers extrude, but donot dehisce. This happens in 15-30

minute then the anthers are easily clipped off. Stigmatic surface is then dusted with pollen grains

collected from the chosen male parent. The crossed panicle is then properly tagged and protected

with paper cover which is retained in a position for 7 – 10 days.

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Rhind’s method

In this method hot water is kept in the flask and it is poured outside . After pouring out

the water inside of the flask will be warm and humid. The panicle to be emasculated will be

inserted into the flask and kept for some time. Due to high temperature and humidity the

spikelets will get opened and the anthers are exposed which can be removed with the help of

forceps.

Wheat ( Triticum aestivum ) (2n = 42 Hexaploid) (Family – Poaceae)

Much of the pollen grains shed within the floret and the crop is largely self pollinated.

The glumes normally open during the flowering process, the anthers protrude from the glumes

and part of the pollen grains is shed outside the flowers. Entry of foreign pollen at flower

opening may result in a small extent of cross pollination which is normally less than one per

cent.

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Selfing

The inflorescence is covered with a butter paper cover prior to anthesis, and kept

undisturbed till the flower opening completed.

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Emasculation

On emergence of the ear upper 1/3rd of the spikelet is cut and lower spikelets are also

removed. Of the remaining spikelets alternate ones on both sides of the axis are removed. The

top spikele is held with forceps and pulled downwards and upwards to remove the upper florets

of the spikelets. The glumes are separated and anthers left exposed are removed carefully and

covered with butter paper cover.

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Crossing

On the next day earhead selected from the pollen parent are used for crossing. The upper

half of the glumes of the few medium spikelets are cut of and the ripened bright yellow anthers

are rubbed on the styles of the emasculated florets and then covered.

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Summary Cheat Sheet

Quick Recall Points

• This lesson focuses on key plant breeding concepts, terminology, and exam-relevant applications.
• Review major definitions, classifications, and method-wise distinctions from the sections above.
• Revise tables and examples from this lesson for fast pre-exam recall.

Exam Traps

• Do not confuse similarly named breeding methods without checking their core selection logic.
• Pay attention to crop-specific examples because the same principle can behave differently by species.

References

1 source • [1]

[1]

Standard Plant Breeding Class Notes (GPBR211)

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