Izindlela zokukhetha

Isiseko sokuphumelela kwanoma yimuphi umsebenzi wokukhethwa ngumsebenzi wezinto eziphilayo kunye neendlela zokukhetha. Ukusetyenziswa kwezixhobo ezinobumba kwenza kube lula ukufumana i-hybri entsha kunye neentlobo, kunye neendlela ezahlukeneyo kunye neepropati. Iziseko zokhetho zibekwe ngabaosayensi abaziwayo kakhulu kwihlabathi:

- H. Mendel (wabeka isiseko semfuza, wafumanisa umgaqo wokungaqondi);

- UCharles Darwin (wasungula imbono yemvelaphi, waqhuba ezininzi iimvavanyo zokuwela);

- UT. Fairchild (ngo-1717 wathabatha iimbobomi zokuqala zokutya);

- II Gerasimov (ufumene utshintsho kwinani leenucleucle kunye neenguqu ezizaliswayo ezihambelana nokuguquka);

- MF Ivanov (uqalise imimiselo yezofuzo ekukhethweni kwezilwanyana) ;

- N. K. Koltsov (wadala isiseko sezityalo zofuzo).

- UNI Vavilov (ufumene umgaqo weengqungquthela zesigxina);

- IV Michurin (ukukhupha iziqhamo ezininzi zesiqhamo).

Izindlela eziphambili zokuzalisa izityalo kunye nezilwanyana ziye zaphuhliswa ngesiseko sazo zonke ezifunyenweyo zangaphambili kwaye ziphuculwe kuze kube namhlanje. Ababelethi emsebenzini wabo basebenzisa iindlela ezahlukeneyo zokukhetha: i-inbreeding, i-mutagenesis yokufakelwa, i-polyploidy, i-hybridation ede. Ngezantsi ziindlela eziqhelekileyo ezisetyenziswayo zokuzalisa izityalo ezintsha kunye nezilwanyana zezilwanyana.

Izindlela ezisisiseko zokuzalisa izityalo: ukuchithwa nokukhethwa. Izityalo eziphambene nomnqamlezo zikhethiweyo ngokukhethwa kwamanani abo bantu abaneempahla ezifunwayo. Ukufumana imigca ecocekileyo, oko kukuthi, i-homogeneity yofuzo lwezinto ezihlukahlukeneyo, ukhetho olukhethiweyo luyasetyenziswa, ngexesha apho ngokuzenzekelayo kwe-pollination isizukulwana senzala evela kumntu oyedwa onayo yonke into ebaluleke kakhulu. Ukungonakali kwile ndlela kukuba ukubonakaliswa okungahambi kakuhle kwemigulo yeengqungquthela ezigqithisileyo kubonwa . Isizathu esibalulekileyo solu ngukuguquka kwenani elikhulu lamajethi kwisimo se-homozygous state. Ngokuhamba kwexesha, ukuqokelela kweengqungquthela zegciwane eziguquguqukayo ezingena kwiimeko zobungqingili zingabangela ukuba utshintsho oluthile luzuze. Kwiimeko zemvelo kwisityalo esizimele, i-genetic genes are homozygous, kwaye isityalo sinjalo ngokukhawuleza.

Xa usebenzisa i-self-pollination, izivuno ziyancitshiswa. Ukwandisa, i-pollination ehamba phambili yemigca yokuhluma izityalo ezihlukeneyo iqhutywayo kwaye ifunyenwe i-hybrids ephezulu. Ezi ndlela zokukhetha zibizwa ngokuba yi-interlinear hybridization. Iimveliso zesizukulwana sokuqala zinesivuno esiphezulu. Kule meko, umphumo owaziwayo we-heterosis uyagcinwa, ngokwemiba enamandla enokuveliswa ngokuwela "imigca ecocekileyo". Abachasene nemiphumo emibi, kuba bephelisa umphumo onobungozi wezakhi zofuzo, kunye nokudibanisa kwezilwanyana ezinamandla ezinamandla zezityalo ziphucula umphumo.

Ngokuqhelekileyo ekukhetheni izityalo ezahlukeneyo, ipolploidy yokulinga isetyenziswa. Izityalo ezifunyenwe ngale ndlela zikhulu ngobukhulu, zivelise isivuno esihle kwaye zikhule ngokukhawuleza. Iipolploids ezibonakalayo ziveliswa ngaphantsi kwefuthe lezinto zamachiza ezonakalisa i-spindle yecandelo. Ngenxa yoko, ii-chromosomes eziphindwe kabini zihlala kwi-nucleus efanayo.

Iindidi ezintsha zithathwa nangendlela ye-mutagenesis yokufakelwa. Umzimba, owathi ngenxa yokuguqulwa komzimba ufumene iipropati ezintsha, unobunzima obuthathaka, ngoko xa ukhetho lwendalo lupheliswa. Ukukhetha kunye nokuziqhelanisa kweentlobo ezintsha kunye nemifuno, abantu abaqhathaniswayo abangathathi hlangothi okanye abaguqukayo abafanelekayo.

Iindlela zokuzalisa izilwanyana azifani kakhulu kwiindlela ezisisiseko zokuzalisa izityalo. Izixhobo zokusebenzisana nabo - ukuzaliswa kwabo ngokwesondo kunye nentwana encinane. Ukukhethwa kwabazali kunye nohlobo lokudlulela kwenziwa ngeenjongo ezithile, ezibekwe ngumfuyi. Zonke izilwanyana zivandlakanywa kungekhona nje ngokubonakala kwazo, kodwa nangomgangatho wabantwana babo kunye nokuzalwa kwabo. Ngako oko, kubaluleke kakhulu ukukwazi ukuhamba kwabo. Xa kuzaliswa, iindlela ezimbini zokudlula zihlala zisetyenziswa:

- Inbreeding (ehlobene kakhulu) - abazali abawela, odade, abazalwana. Ukuwela okunjalo akunakwenziwa ngonaphakade. Isetyenziswa, njengommiselo, ukuphucula iipropati zelawa;

- Ukuqhekeka (okungahambelaniyo) - ukuwela kwamalungu abemi okanye iintlobo ezahlukeneyo kunye nokukhethwa ngokuqinileyo kweenzala ezinezixhobo ezingcono.

Ukuchithwa kwezilwanyana zasemaphandleni akusebenzi kangangoko kunokuba uhlalutyo lwezityalo. Ezi zixhobo ze-hybrids zihlala zingenamandla.