Broadening the Genetic Base of Wheat Using Primary Hexaploid Synthetics.

Wheat (Triticum aestivum L.) improvement from intercrosses of existing elite materials has narrowed the genetic diversity of the crop resulting in a slower genetic gain. The potential use of synthetic hexaploid wheat to enhance breeding outcomes is well known. However, the success of synthetic hexaploid wheat utilization in breeding could have been much higher if they were guided by the knowledge of genes controlling biotic (diseases) and abiotic (drought and cold) stresses. The main goal of this research was to identify superior primary synthetics possessing resistance to diseases, cold, and drought, identify the respective genes and develop molecular markers that can be used for marker assisted transfer of the genes in to high yielding modern wheat germplasm. Primary synthetic hexaploid wheat (126) developed by CIMMYT and Kyoto University (Japan) were used to assess the genetic diversity for biotic and abiotic stresses. Preliminary phenotypic data had resistance to cereal cyst nematode (11 entries), common bunt (46), stem rust (21), leaf rust (80), stripe rust (13), crown root rot (3), and barley yellow dwarf virus (15). A number of these synthetics had significantly higher grain yield (7 entries) and comparable flour protein concentration to the checks (Gerek and Karahan) under drought stressed environment. Thus, primary hexaploid synthetics represent valuable sources for broadening the genetic base of elite wheat breeding germplasm.

Keywords: biotic and abiotic stresses, resistance, drought, genes, genetic diversity