Sunday, February 19, 2012
Exhibit Hall A-B1 (VCC West Building)
Sorghum is used worldwide for grain, carbohydrate and forage and is a potential biofuel feedstock. It may be possible to improve sorghum’s utility through modification of its genome, however, protocols for sorghum transformation are not well developed and there is little understanding of how transformation is affected by genotype and in vitro cultivation conditions. Hence, the purpose of this study is to determine optimal sorghum genotypes for the production of somatic embryogenic callus suitable for transformation, and how transformation efficiency is affected by several culture media. Seven diverse sorghum genotypes (including grain sorghum, forage sorghum and sweet sorghum) obtained from the USDA-ARS/GRIN germplasm collection were germinated and raised in a controlled environment. Following flowering and self-pollination, immature seeds were collected, their embryos isolated and sterilized and placed on callus induction medium (Kaeppler) at 28 Every 2 weeks the formation of somatic embryogenic calli were evaluated. Varieties Tx2737, P898012, and Tx430 exhibited high callus induction (>95%), Wheatland-1 displayed a 36% induction rate, whereas varieties Lr401, RIO, and N592 exhibited low callus induction (<35 %). Embryos from the first group were transferred to fresh media for regeneration and transformation studies, which are ongoing. Media differing in the content of potassium phosphate (Elkonin and Pakhomova) will be evaluated for effectiveness in supporting development of somatic embryogenic callus. Fragile embryogenic calli will be transferred to regeneration media, evaluated and assessed for transformation with Agrobacteria using bar as the selectable marker.