Determination and evaluation of Puroindoline Alleles in CIMMYT wheats

【Objective】Grain hardness,controlled by a hardness(Ha) gene,serves as a basis for classification and marketing of common wheat(Triticum aestivum L.) quality and has a profound effect on milling and end-use quality.CIMMYT is one of the most important places that regularly offer germplasm to Chinese wheat breeding program.This study can provide useful information to introduce wheat to China.【Method】 A total of 236 wheat lines from CIMMYT crossing program,including common wheat cultivars and advanced lines derived from synthetic hexaploid wheat × common wheat crosses,are used to detect variation of puroindoline alleles by specific-primers PCR amplification and modified SDS-PAGE.PSI(particle size index) hardness was also measured for 160 genotypes.【Result】 Results indicated that 165 hard wheat lines are Pina-D1b types and the remaining 37 are Pinb-D1b types,which are non-CIMMYT cultivars or their pedigrees contain non-CIMMYT cultivars.Pina-D1j/Pinb-D1i,Pina-D1c/Pinb-D1h,Pina-D1a-Pinb-D1i,Pina-D1a-Pinb-D1j,and wild type(Pina-D1a/Pinb-D1a) are present in 34 soft types.Genotypes with Pina-D1b are significantly harder(lower PSI hardness) than genotypes with Pinb-D1b.Genotypes with Pina-D1c/Pinb-D1h and Pina-D1a/Pinb-D1i are significant harder(lower PSI hardness) than genotypes with Pina-D1j/Pinb-D1i and Pina-D1a/Pinb-D1a.In addition,both Pinb-D1h and Pinb-D1i encode the same polypeptides and a tryptophan substitute(arginine) at position 28,which is the major reason for soft endosperm.In comparison with wild type(Pina-D1a/Pinb-D1a),no change was found in close to tryptophan-rich domain of puroindoline in other soft genotypes except for Pinb-D1h and Pinb-D1i,which may be the main reason that mutation types still remain soft endosperm.【Conclusion】 It is concluded that all of Pinb-D1b types are non-CIMMYT cultivars or their pedigrees contain non-CIMMYT cultivars and PSI of puroindoline alleles from Ae.tauschii are difference.