Hand-pollination is a technique used to pollinate plants when natural or open pollination is either undesirable or insufficient. It involves the manual transfer of pollen from the stamen of a male flower to the stigma of a female flower. This can be done either by removing the petals of a male flower to expose its stamen, which will then be brushed against the receptive stigma of a female blossom in order to deposit the pollen; or by using a small brush or swab. The female flower is then closed to prevent any pollen contamination from external sources. Besides its simplicity, hand-pollination helps to keep control of cross-pollination between varieties grown together.
In commercial breeding operations, this method is commonly used to create intentional crosses and produce hybrids seeds. It is a laborious process–as it frequently involve the emasculation of flowers–that is often delocalized in regions where labor is inexpensive. For the garden seed saver, hand-pollination will mainly be used with monoecious plants, especially members of the Cucurbitaceae family as well as corn to prevent cross-pollination and therefore maintain the genetic purity of a variety.
For some self-pollinated crops such as tomatoes that require wind or buzzing insects (or conditions that mimic it) and where either of them is lacking (i.e.: in a greenhouse), each plant can be lightly shaken up to imitate a breeze or the vibration of certain bees and promote pollen shed. Flowers can also gently be tapped individually. Timing is key, as pollen shed normally occurs from morning to late afternoon, with midday being the ideal time for release and transfer (note that some pollen transfer can still occur in less than optimal weather). This technique–less tedious than using a brush–will ultimately assist the flowers in inducing the process of fertilization and improve fruit set.
Specific hand-pollination techniques for applicable crops are discussed in Section VII.
Hand-pollination ni mbinu kutumika kwa pollinate mimea wakati asili au wazi pollination ni ama yasiyotakiwa au haitoshi. Ni kazi ya mikono ya kuhamisha chavua kutoka kwenye mti wa maua ya kiume hadi kwenye mti wa maua ya kike. Hii inaweza kufanywa ama kwa kuondoa petals ya maua ya kiume ili kufunua stamen yake, ambayo kisha itakuwa brushed dhidi ya stigma ya kupokea ya maua ya kike ili kuweka chavua, au kwa kutumia brush ndogo au swab. Kisha ua la kike hufungwa ili kuzuia uchafuzi wowote wa chavua kutoka vyanzo vya nje. Mbali na kuwa rahisi, kupandikiza kwa mikono husaidia kudhibiti kupandikizwa kwa msalaba kati ya aina zinazokua pamoja. Katika shughuli za kibiashara za uzalishaji, njia hii hutumiwa kwa kawaida kuunda msalaba wa makusudi na kuzalisha mbegu za mseto. Ni mchakato wa kazi ngumu - kwani mara nyingi huhusisha kuondolewa kwa maua - ambayo mara nyingi huhamishwa katika mikoa ambapo kazi ni ya bei nafuu. Kwa ajili ya kuhifadhi mbegu ya bustani, pollination ya mkono itatumiwa hasa na mimea ya monoecious, hasa wanachama wa familia ya Cucurbitaceae, pamoja na mahindi ili kuzuia pollination msalaba na hivyo kudumisha usafi wa maumbile ya aina. Kwa baadhi ya mazao ya self-pollinated kama vile nyanya ambayo zinahitaji upepo au buzzing wadudu (au hali ambayo kuiga) na ambapo yoyote ya yao ni kukosa (yaani, Katika mazingira ya kijani kibichi, mimea inaweza kutikiswa kidogo ili kuiga upepo au vibration ya nyuki fulani na kuendeleza pollen shed. Maua yanaweza pia kugongwa kwa upole moja kwa moja. Wakati ni muhimu, kama pollen shedding kawaida hutokea kutoka asubuhi hadi alasiri marehemu, na mchana kuwa wakati bora kwa ajili ya kutolewa na uhamisho (kumbuka kwamba baadhi ya uhamisho wa chavua bado inaweza kutokea katika hali ya hewa chini ya bora). Mbinu hii - isiyochosha sana kuliko kutumia brashi - hatimaye itasaidia maua kuchochea mchakato wa mbolea na kuboresha seti ya matunda. Mbinu maalum za kupandikiza kwa mkono kwa mazao yanayotumika zinajadiliwa katika Sehemu ya VII.