Evaluation of sweet sorghum accessions for seedling cold tolerance using both lab and field cold germination test

Authors: Wang, Ming; Xin, Zhanguo; Burow, Gloria; Chen, Junping; Vankus, Phiffie; Pinnow, David; Tonnis, Brandon; Cuevas, Hugo; YU, JIANMING - Iowa State University

Submitted to: Journal of Agricultural Science and Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2017
Publication Date: 11/6/2017
Citation: Wang, M.L., Xin, Z., Burow, G.B., Chen, J., Vankus, P.J., Pinnow, D.L., Tonnis, B.D., Cuevas, H.E., Yu, J. 2017. Evaluation of sweet sorghum accessions for seedling cold tolerance using both lab and field cold germination test. Journal of Agricultural Science and Botany. 1(1):1-8.

Interpretive Summary: Cultivars with quick seedling emergence and stand establishment at early spring cold conditions may be planted early in the same region with an extended period of plant growth and can potentially increase either grain yield, stem sugar yield, or biomass production of sorghum. Planting cultivars with early spring cold tolerance may also expand sorghum planting geographic regions or allow multiple harvests within a growing season. Research on early spring cold tolerance in grain sorghum is well documented, but very limited information is available on sweet sorghum. Screening of 212 sweet sorghum accessions (selected from the USDA germplasm collection) plus four checks for the early spring cold tolerance was conducted under both lab and field conditions. In this study, a high correlation coefficient between lab germination rate and field germination rate (R2 = 0.503, p <0.0001) was observed. In general, lab germination rate can predict the field germination performance; but some discrepancies between field and lab tests were also observed for some accessions. The correlation coefficient of seedling dry weight with the field germination rate was much higher (R2 = 0.257, p <0.0001) than with the lab germination rate (R2 = 0.109, p <0.05). Several sweet sorghum accessions with seedling cold tolerance were identified from both lab and field tests. These accessions will be useful materials for development of sweet sorghum cultivars with early spring cold tolerance. In addition, 652 more sweet sorghum accessions were only screened in the lab for seedling cold tolerance. Those accessions identified with good seedling cold tolerance in the lab need to be further confirmed by the field experiment. Seed dormancy can directly affect seed germination rate. The relationship between seed dormancy and germination rate from this study is also discussed.

Technical Abstract: Cultivars with quick seedling emergence and stand establishment at early spring cold conditions may be planted early in the same region with an extended period of plant growth and can potentially increase either grain yield, stem sugar yield, or biomass production of sorghum. Planting cultivars with early spring cold tolerance may also expand sorghum planting geographic regions or allow multiple harvests within a growing season. Research on early spring cold tolerance in grain sorghum is well documented, but very limited information is available on sweet sorghum. Screening of 212 sweet sorghum accessions (selected from the USDA germplasm collection) plus four checks for the early spring cold tolerance was conducted under both lab and field conditions. In this study, a high correlation coefficient between lab germination rate and field germination rate (R2 = 0.503, p <0.0001) was observed. In general, lab germination rate can predict the field germination performance; but some discrepancies between field and lab tests were also observed for some accessions. The correlation coefficient of seedling dry weight with the field germination rate was much higher (R2 = 0.257, p <0.0001) than with the lab germination rate (R2 = 0.109, p <0.05). Several sweet sorghum accessions with seedling cold tolerance were identified from both lab and field tests. These accessions will be useful materials for development of sweet sorghum cultivars with early spring cold tolerance. In addition, 652 more sweet sorghum accessions were only screened in the lab for seedling cold tolerance. Those accessions identified with good seedling cold tolerance in the lab need to be further confirmed by the field experiment. Seed dormancy can directly affect seed germination rate. The relationship between seed dormancy and germination rate from this study is also discussed.