Grain hardness has a considerable effect on milling yield, particle size, and water absorption of wheat (Triticum aestivum L.) flour and is considered an integral trait in wheat end-use classification. Kernel hardness in wheat is controlled by the Hardness locus on chromosome 5D. In this study, we investigated genotypic variation of genes involved in grain hardness in wheat cultivars developed in Iran or CIMMYT. We have used two allele-specific PCR marker methodologies to identify allelic variation of Pina-D1 and Pinb-D1 genes. We also determined the force required for seed rupture by compression testing (CT) in selected number of cultivars. Two alleles (Pina-D1a and Pina-D1b) for Pina-D1 and three alleles (Pinb-D1a, Pinb-D1b, and Pinb-D1d) for Pinb-D1 were detected. The most common genotype observed was Pina-D1a/Pinb-D1a. The second most frequent genotype was Pina-D1b/Pinb-D1a. Genotypes Pina-D1a/Pinb-D1d and Pina-D1b/Pinb-D1d were also observed but at very low frequencies. In general, compression testing data were in agreement with the grain hardness expected from each genotypic class. Most Pina-D1b-carrying germplasm were those from the CIMMYT global wheat program. The allele Pinb-D1d was found in combination with Pina-D1a and with Pina-D1b. The allele Pinb-D1d did not increase grain hardness as expected.
Bibliographical noteFunding Information:
This work was financially supported by the Seed and Plant Improvement Institute, Iran, under grant number 2-03-03-90018 to Mohsen Mohammadi. The authors are thankful to staff at the Cereals Chemistry Laboratory at CRD SPII for technical help and to Department of Agricultural Technical Engineering, College of Aburaihan, University of Tehran, for use of compression testing machine. Special thanks are extended to Dr. William Yajima for providing critical reading and editorial input.
- allele-specific markers
- compression test
- end-use quality traits
- hardness locus
- kernel hardness