The possibilities of applying marker assisted selection in breeding boron tolerant wheat

Abstract

The aim of this study was to investigate the possibilities of applying molecular markers-microsatellites in breeding boron tolerant wheat. The study comprised the investigation of allelic variability of sixty bread wheat accessions in two microsatellite loci (Xgwm46-7B and Xgwm577-7B) for which was assumed that are placed near the 7B chromosome locus involved in the expression of boron tolerance in wheat. Phenotypic variability concerning boron tolerance was assessed via root length reduction of wheat seedlings grown in the presence of high external boron, applied as boric acid solution (concentrations 50, 100 and 150 mg/l, boron treatments B50, B100 and B150). The indication of marker-trait associations was determined by comparing the allelic variability in the two microsatellite loci with the phenotypic variability in boron tolerance. Nonparametric Kruskal-Wallis test was used for the comparisons. The indication of marker-trait association was found for both Xgwm46-7B and Xgwm577-7B; on B150 and B50 treatments, respectively. Allelic forms identified in Xgwm577-7B locus may be related to tolerance, medium tolerance and sensitivity to high boron. This was not the case for Xgwm46-7B, where the identified alleles were related only to boron tolerance and sensitivity. Therefore, Xgwm577-7B may be preferred over Xgwm46-7B when studying boron tolerance in wheat. However, a considerable portion of boron tolerant accessions carried different alleles in the investigated loci, implying boron tolerance as a quantitative trait with more than one chromosomal region involved in its expression. Therefore, the allelic variability of more than the analyzed two loci should be investigated.

Cilj ovog rada je bilo ispitivanje mogućnosti primene molekularnih markera-mikrosatelita u oplemenjivanju pšenice tolerantne na bor. Ispitana je alelna varijabilnost kod šezdeset genotipova hlebne pšenice u dva mikrosatelitna lokusa (Xgwm46-7B i Xgwm577-7B) za koje se pretpostavlja da su pozicionirani u blizini lokusa na 7B hromozomu koji utiče na ekspresiju ovog svojstva. Fenotipska varijabilnost u pogledu tolerantnosti na bor je utvrđena na osnovu redukcije dužine korenčića klijanaca pšenice gajenih u uslovima suviška bora (rastvor borne kiseline koncentracija 50, 100 i 150 mg/l, tretmani B50, B100, B150). Indikacija veze marker-svojstvo je utvrđivana na osnovu poređenja alelne varijabilnosti mikrosatelitnih lokusa i fenotipske varijabilnosti u pogledu tolerantnosti na bor. Za poređenja je korišćen neparametarski Kruskal-Wallis test. Indikacija veze marker-svojstvo je konstatovana za Xgwm46-7B na tretmanu B150, a za Xgwm577-7B na tretmanu B50. Alelne forme identifikovane u lokusu Xgwm577-7B se mogu dovesti u vezu sa tolerantnošću, srednjom tolerantnošću i osetljivošću na bor. Ovo nije bio slučaj kod Xgwm46-7B, gde su identifikovani aleli dovedeni u vezu samo sa tolerantnošću i osetljivošću na bor. Prema tome, za dalji rad se preporučuje Xgwm577-7B. Međutim, kod značajnog dela tolerantnih genotipova su identifikovani različiti aleli u proučavanim lokusima, što upućuje na zaključak da je u pitanju kvantitativno svojstvo u čiju ekspresiju je uključeno više od jednog hromozomskog regiona. Potrebno je ispitati alelnu varijabilnost više od dva mikrosatelitna lokusa.