Impact of genotype, seed composition, agronomic trait and environment on soybean test weight

Authors: LIU, LIKE - University Of Georgia; PRENGER, ELIZABETH - University Of Georgia; ZHANG, JUN - University Of Georgia; LITTLE, BRIAN - University Of Georgia; Mian, Rouf; LI, ZENGLU - University Of Georgia

Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2019
Publication Date: 9/5/2019
Citation: Liu, L., Prenger, E.M., Zhang, J., Little, B., Mian, R.M., Li, Z. 2019. Impact of genotype, seed composition, agronomic trait and environment on soybean test weight. Journal of Crop Improvement. 33:6, 711-729. https://doi.org/10.1080/15427528.2019.1659205.
DOI: https://doi.org/10.1080/15427528.2019.1659205

Interpretive Summary: Soybean test weight (TW) is used as an indicator of its grain quality and can be used for determining the price of the grain. The objectives of this research were to: (i) evaluate the effects of genotypes, environments and planting dates on TW, and (ii) determine the relationship of TW with agronomic and seed composition traits. Six experiments (Exp) were conducted using diverse sets of experimental lines. Significant variations of TW among genotypes were observed, ranging from 70.3 to 76.5 kg hL-1, 70.0 to 74.0 kg hL-1, and 68.9 to 73.1 kg hL-1 in Exp-1, 2, and 3, respectively. Locations and G x E interactions had significant effects on TW (P < 0.001) in these experiments. Seed protein content was positively correlated with TW in Exp-1, 3, and 4, while seed oil content was negatively correlated with TW across experiments. Seed size was negatively correlated with TW across experiments except for Exp-3, and sucrose content was positively correlated with TW in all but Exp-4. Maturity day was positively correlated with TW across experiments, while yield was negatively correlated with TW in Exp-1 and 3. The effects of planting dates on TW were inconsistent across years. TW decreased about 0.22 kg hL-1 for each one percent increase in seed moisture between of 5 to 18%. Direct selection of TW was better than indirect selection based on the other traits. The results of this research indicate that TW of soybean seed can be slightly improved by increasing seed protein or reducing seed oil content.

Technical Abstract: Test weight (TW) is a primary indicator of soybean grain quality and measure of bulk density. The objectives of this research were to: (i) evaluate the effects of genotypes, environments and planting dates on TW, and (ii) determine the relationship of TW with agronomic and seed composition traits. Six experiments (Exp) were conducted using diverse sets of experimental lines. Significant genetic variations (P < 0.001) of TW among genotypes were observed, ranging from 70.3 to 76.5 kg hL-1, 70.0 to 74.0 kg hL-1, and 68.9 to 73.1 kg hL-1 in Exp-1, 2, and 3, respectively. Locations and G x E interactions had significant effects on TW (P < 0.001) in these experiments. Seed protein content was positively correlated with TW in Exp-1, 3, and 4, while seed oil content was negatively correlated with TW across experiments. Seed size was negatively correlated with TW across experiments except for Exp-3, and sucrose content was positively correlated with TW in all but Exp-4. Maturity day was positively correlated with TW across experiments, while yield was negatively correlated with TW in Exp-1 and 3. A significant positive correlation between height and TW was only found in Exp-3. Planting dates effects on TW were inconsistent across years. TW decreased about 0.22 kg hL-1 for each one percent increase in seed moisture between of 5 to 18%. Direct selection of TW was better than indirect selection based on the other traits. The results in this research could be used to guide future genetic improvement of TW.