Genomic breeding for accelerated improvement of growth, wood properties and plant defence in Eucalyptus grandis

Abstract

English; A significant benefit of genomic selection (GS) in forest trees is to reduce breeding cycle times and increase gains per unit time. Flowering time (seed-to-seed) of many forest tree species is a crucial factor contributing to the length of breeding cycles. In this study, we investigated the benefits of combining GS with transgenic Flowering locus T (FT)-scion for early floral induction (GS-FT) transgrafting approach in the precocious Eucalyptus grandis and non-precocious E. dunnii, two economically important plantation species. We simulated traditional breeding (TB), GS and GS-FT in the species and compared their transitional cost ratio and their benefit-cost ratio in terms of genetic gain. Implementation of GS and GS-FT compared to TB strategy was 10 to 13.8 fold more expensive for both species. Whereas the transition from GS to GS-FT strategy in both species is 1.2 fold more expensive. This resulted in a punitive benefit-cost ratio implementing GS and GS-FT strategies compared to the TB strategies. The implementation of the GS-FT, compared to the GS strategy, had a profitable benefit-cost ratio. With the adoption of the GS-FT strategy, which effectively removes flowering time as a barrier, similar breeding cycle times are achieved in both species, but E. dunnii benefits more due to the significant reduction in breeding cycle time. Our simulation provides a first indication of the potential benefits of implementing FT floral induction in conjunction with GS breeding strategies in plantation forest species.

Sepedi: Mohola wo mogolo wa kgetho ya tšenomiki (GS) ka mehlareng ya dithokgwa ke go fokotša modikologo wa dinako tša go gola le go oketša dipoelo ka Nakong ya yuniting e tee. Nako ya go thunya matšoba (go tšwa peung go ya peung) ya mehuta ye mentši ya mehlare ya sethokgwa ke selo se bohlokwa seo se nago le seabe boteleleng bja ditikologo tša kopanyo. Ka thutong ye, re nyakišišitše mehola ya go kopanya GS le Scion (FT) ya semela yeo e fetotšwego e bile e nale loukhase T ya go tliša go thunya) go hlohleletša tšweletšo ya matšoba a mathomo ka pela(GS-FT) ka go mokgwa wa go tswakanya go Eucalyptus grantis ya go thunya ga matšoba ka pele le E. dunnii yeo e sa thunyego ya pele ga nako, mehuta ye mebedi ya dipolantase ye bohlokwa ikonoming. Re ile ra ekiša tswadišo ya setšo ya (TB), GS le GS-FT mehuteng ya diphedi gomme ra bapetša tekanyo ya tšona ya ditshenyagalelo tša phetogo le tekanyo ya tšona ya ditshenyegelo tša mohola go ya ka poelo go leabela. Go tsenywa tirišong ga GS le GS-FT ge go bapetšwa le leano la TB ya bitša ya makga a 10 go ya go 13.8 mehuteng ye ka bobedi. Mola phetogo go tšwa go leano la GS go ya go GS-FT ka mehuteng ye ka bobedi e bitša makga a 1.2 go feta. Se se feleleditše ka tekanyo ya dikholego ya tshenyegelo ya kotlo yeo e phethagatšago maano a GS le GS-FT ge a bapetšwa le maano a TB. Go tsenywa tirišong ga GS-FT, ge go bapetšwa le leano la GS, go bile le tekanyo ya dikholego tša tshenyagalelo yeo e nago le poelo. Ka go amogela leano la GS-FT, leo le šomago gabotse go tloša lepheko la nako ya go thunya, dinako tša go swana tša tikologo ya tswadišo di a fihlelelwa ka mehuta ye ka bobedi, eupša E. dunnii e holega kudu ka lebaka la phokotšo ye kgolo ya nako ya tikologo ya tswadišo. Go ekiša ga rena go fa taetšo ya mathomo ya mehola ye e ka bago gona ya go phethagatša tsenyo ya FT floral e kopantšwe le maano a tswadišo a GS ka mehuteng ya dibjalo tša dithokgwa.

Afrikaans: n Beduidende voordeel van genomiese seleksie (GS) in bosbome is om teelsiklustye te verminder en winste per eenheid tyd te verhoog. Bloeityd (saad tot saad) van baie bosboomspesies is 'n deurslaggewende faktor wat bydra tot die lengte van teelsiklusse. In hierdie studie het ons die voordele ondersoek van die kombinasie van GS met transgeniese Blomlokus T (FT)-ent vir vroeë blominduksie (GS-FT) transentingbenadering in die vroegtydige Eucalyptus grandis en nie-vroegtydige E. dunnii, twee ekonomies belangrike plantasiespesies. Ons het tradisionele teling (TB), GS en GS-FT in die spesie gesimuleer en hul oorgangskosteverhouding en hul voordeel-kosteverhouding in terme van genetiese wins vergelyk. Die implementering van GS en GS-FT in vergelyking met die TB-strategie was 10 tot 13,8 keer duurder vir beide spesies. Die oorgang van GS na GS-FT-strategie in beide spesies is 1,2 keer duurder. Dit het gelei tot 'n punitiewe voordeel-koste-verhouding met die implementering van GS- en GS-FT-strategieë in vergelyking met die TB-strategieë. Die implementering van die GS-FT, in vergelyking met die GS-strategie, het 'n winsgewende voordeel-koste-verhouding gehad. Met die aanvaarding van die GS-FT-strategie, wat effektief blomtyd as 'n hindernis verwyder, word soortgelyke teelsiklustye in beide spesies bereik, maar E. dunnii trek meer voordeel as gevolg van die beduidende vermindering in teelsiklustyd. Ons simulasie bied 'n eerste aanduiding van die potensiële voordele van die implementering van FT-blominduksie in samewerking met GS-teelstrategieë in plantasiebosspesies.

IsiZulu: Inzuzo enkulu yokukhethwa kwezakhi zofuzo (i-genomic selection (i-GS)) ezihlahleni zasehlathini ukunciphisa izikhathi zomjikelezo wokuzalanisa nokwandisa izinzuzo ngesikhathi seyunithi ngayinye. Isikhathi sokuqhakaza (kwimbewu-ukuya-kwimbewu) yezinhlobo eziningi zezihlahla zasehlathini wuphawu olusemqoka olunomthelela kubude bemijikelezo yokuzalanisa. Kulolu cwaningo, siphenye izinzuzo zokuhlanganisa i-GS ne-transgenic flowering locus T (FT) -scion ukuze kungeniswe ukuqhakaza kusenesikhathi (i-GS-FT) isu lokudluliswa kwamathishu okungahambisani nokunengqondo kwe-Eucalyptus grandis kanye nokungena ngqondo kwe-E. dunnii , izinhlobo ezimbili zezitshalo ezibalulekile ngokwezomnotho. Salingisa ukuzalanisa kwendabuko (i-TB), i-GS kanye ne-GS-FT ezinhlotsheni futhi saqhathanisa isilinganiso sezindleko sazo sokuguquka kanye nesilinganiso sezinzuzo sazo ngokuphathelene ne yamajini. Ukusetshenziswa kwe-GS ne-GS-FT uma kuqhathaniswa nesu le-TB kwakubiza ngokuphindwe ka-10 ukuya ku-13.8 kuzo zombili zinhlobo. Nakuba ukudlulela kwesinye isimo kwe--GS ukuya ku--GS-FT kuzo zombili lezi zinhlobo kubiza ngokuphindwe kuka-1.2 . Lokhu kube nomphumela ojezisayo wokusebenzisa i-GS kanye ne-GS-FT esilinganisweni sezindleko-zenzuzo uma kuqhathaniswa namasu e-TB. Ukusetshenziswa kwe-GS-FT, uma kuqhathaniswa nesu le-GS, kube nesilinganiso sezindleko- zenzuzo esinikeza inzuzo. Ngokwamukelwa kwesu le-GS-FT, elisusa ngokuphumelelayo isikhathi sokuqhakaza njengokuvimbelayo, izikhathi ezifanayo zomjikelezo wokuzalanisa zifinyelelwa kuzo zombili izinhlobo, kodwa i-E. dunnii izuza kakhulu ngenxa yokuncipha okuphawulekayo kwesikhathi somjikelezo wokuzalanisa. Ukulingisa kwethu kuhlinzeka inkomba yokuqala yezinzuzo ezingaba khona zokusebenzisa ukufakwa kwezimbali kwe-FT ngokuhambisana namasu okuzalanisa e-GS ezinhlotsheni zezitshalo zamahlathi.