Posted on Dec 01, 2009
Sorghum is well known for its drought tolerance and overall adaptation to high temperature. At the other end of the temperature spectrum, sorghum generally lacks cold tolerance and is vulnerable to cool temperature, specifically during stand establishment in early season planting from April to May in most areas of the US sorghum belt. Stand establishment and early season vigor of sorghum is adversely affected by air and soil temperatures below 60ºF (15°C) during germination, emergence and early seedling growth. Cold tolerance is recognized as a crucial factor for increasing yields, both allowing farmers to capitalize on early season moisture and also that fuller season varieties with higher yield potential may be developed. Fortunately, excellent sources of cold tolerance have been identified within the sorghum gene pool, and steps have been taken to begin the process of developing the tools needed to bring these genetic resources to market.
To support the need for cold tolerant germplasm, the sorghum improvement project at the USDA-ARS –Lubbock, TX initiated and pursued research efforts aimed at the identification of sources of cold tolerance and development of genetic resources for the transfer of cold tolerance traits to U.S.-adapted sorghum. Furthermore, genomic tools such as DNA markers have been created in the program, to facilitate the application of marker technology to the overall improvement of sorghum. This proposed project focuses on the utilization of an advanced Recombinant Inbred Line (RIL) population specifically designed to be used as a tool for understanding cold tolerance, through a synergistic collaboration between public programs (USDA-ARS, KSU) and a private company (Advanta U.S., Hereford TX). We will carry out a comprehensive evaluation of cold tolerance across three locations within the U.S. grain sorghum belt and characterize a sizeable number of F6 lines to pinpoint genetic regions associated with cold tolerance. The identification of Quantitative Trait Loci (QTL) will enable the rapid development of cold tolerant sorghum hybrids through the use of Marker Assisted Selection (MAS). To better understand the inheritance of this trait and to determine the most effective means of hybrid development, we will also create F1 hybrids between sterile versions of Chinese sources of cold tolerance and elite US A/B lines. This will provide estimates of the performance of these traits in hybrid combination and assess the importance of seed parent vs. pollinator in cold tolerance. Finally, the project will disseminate marker technology to sorghum researchers by providing ready-to-use DNA markers that cover the whole genome.
This proposal will address the issue of sorghum cold tolerance in an integrated fashion that facilitates the analysis and characterization at both the whole plant and molecular level. We will deliver a platform for gene identification and DNA marker tools that will facilitate the breeding of both grain and forage sorghum with enhanced cold tolerance. The project is envisioned to directly benefit sorghum producers and promote the core values of the sorghum check off board thru research through the establishment of public-private sector partnerships.