Expanding the technology base for Norwegian wheat breeding: genomic tools for breeding of high quality bread wheat

EXPAND is a collaborative project between Graminor, Strand Unikorn, Norgesmøllene, BKLF, NMBU and Nofima. The project focuses to improve pre-harvest sprouting (PHS) resistance of bread wheat to sustain good bread making quality under the challenging Norwegian and Nordic climate. In the project, we use the PHS trait to implement genomic tools (i.e. GS) in the Norwegian wheat breeding. PHS is the single most important quality-degrading factor of wheat in Norway and other Nordic regions with similar environmental challenges. While wheat cultivars on the Norwegian market have the genetic potential for bread-making quality, this potential is often destroyed by pre-harvest sprouting, caused by delayed harvest due to rainy weather. Therefore, it is essential for project consortium to develop cultivars with improved resistance to PHS to serve the Norwegian cereal farmers. In this project we are using an association mapping panel (MASBASIS) consisting of 299 spring wheat cultivars and breeding lines and several biparental mapping populations for genetic studies and genetic mapping of PHS resistance in Norwegian wheat. These are being tested in field trials over four years at two locations in Norway (Vollebekk and Staur) and/or in Chengdu, China for relevant traits related to PHS resistance, with focus on germination Index (GI) to assess the level of seed dormancy and Falling Number (FN) to assess the level of sprouting damage when plants are exposed to rain after maturity. In addition to natural rain, some of the trials at Vollebekk have also been subjected to mist irrigation to provoke sprouting. The testing of two bi-parental populations of crossings between breeding lines/cultivars, which are differ in their PHS resistance have been completed and the mapping results are now being written up for publication. In addition, a major and consistent QTL for falling number was mapped on chromosome 4BL in another population. The PHS phenotypes show strong interactions with the environmental conditions, and this have initiated some modeling work to include weather parameters in the genomic prediction models. To further investigate the genetics of PHS resistance, a mapping population was developed based on the highly PHS resistance wheat breeding line, T7347. Advanced lines from this population were tested in the field in 2018 and 2019 and the data was used to select 16 extreme lines transcriptomic study. The purpose of the transcriptome study is to identify transcripts involved in the PHS resistance of T7347 and identify molecular markers for mapping of the trait. GI analyses of fresh immature seeds confirmed the expected difference in dormancy between the parental lines. A total of 108 seed samples have been dissected to obtain embryos, aleurone layers and starchy endosperm, the cell types that are known to be involved in the PHS trait. Extraction of RNA from these tissue samples is in its final stage, and we expect to have submitted samples for RNA sequencing before the end of this year. Another important goal of this project is to develop and implement GS in our national wheat breeding program. By using advanced statistic models, we have now developed potential models to implement GS in our national breeding. these models will be further validated in an independent breeding populations before implementation. In the last period we have further genotyped the association mapping panel and the two parental populations to confirm the QTLs we identified earlier. We have also performed additional genotyping and phenotyping of a breeding set of material (300) to validate the identified molecular markers and GS models for breeding usage.

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Den politiske målsettingen om økt norske matproduksjonen forutsetter en økning i produksjonen av norsk hvete til mat. Alle hvetesortene på det norske markedet i dag har det genetiske potensialet som trengs for god bakekvalitet, men denne kvaliteten blir ofte ødelagt av aksgroing på grunn av utsatt høsting som følge av regn. Manglende resistens mot aksgroing er den viktigste årsaken til nedklassifisering av hvete til fôr både i Norge og våre naboland med lignende klima, og påfører bønder, mølle- og bakeindustrien store økonomiske tap. For Graminor er det et viktig strategisk grep å utvikle sorter med økt resistens mot aksgroing. Dette vil gi økte markedsandeler for Graminors hvetesorter i Norge og Norden styrke selskapets konkurransekraft. Det har de siste årene skjedd en rivende utvikling innenfor genomikk på hvete, og Graminor har investert stort i flere pågående forskningsprosjekter, blant annet innen genomsekvensering, markørteknologier og genomseleksjon. Hovedmålsettingen med dette prosjektet er å utnytte disse nye teknologiene til å utvikle nye og effektive foredlingsmetoder. Resistens mot aksgroing vil bli brukt som et case i dette prosjektet, men metodene som utvikles skal anvendes på alle viktige egenskaper. Molekylære markører vil bli utviklet basert på genetiske studier av aksgroingsresistens i det norske hveteforedlingsmaterialet i samarbeid med NMBU, Nofima og andre internasjonalt ledende forskningsmiljø. Genomseleksjonsmodeller vil også bli utviklet i samarbeid med Nofima. Disse metodene vil bli testet og validert på reelle data, og implementert i Graminors hveteforedlingsprogram. Resultatet vil bli en mer effektiv hveteforedling som svarer til markedets behov for nye sorter med bedre tilpasning til framtidig klima, og økt konkurransekraft for Graminor som et ledende nordisk planteforedlingsfirma.