RESUMO
To produce high quality, glyphosate-resistant soybeans, we crossed Jinda 73 and glyphosate-resistant RR1 (Roundup Ready First Generation) (RR1) resulting in 34 hybrid strains. To determine the effects of glyphosate on soybean metabolism, we grew the two parents upto the seedling stage, and measured chlorophyll, soluble sugar, malondialdehyde (MDA), relative conductivity and proline. Then, we treated the plants with glyphosate and measured the same factors again. Results showed that the chlorophyll content of Jinda 73 and RR1 decreased after spraying glyphosate. Glyphosate increased the level of soluble sugar, MDA, relative conductivity and proline in Jinda 73, but had no significant effect on RR1. We determined glyphosate resistance of the parents and the 34 hybrid, offspring strains by documenting the growth response in the field after treatment with glyphosate. Results showed that 29 hybrid, offspring strains have complete glyphosate resistance. Polymerase chain reaction (PCR) shows that the strains which have complete resistance to glyphosate have imported the CP4 5-enolpyhruvylshikimate-3- phosphate synthase (CP4 EPSPS) gene successfully. We selected three high quality, glyphosate-resistant strains (F7-3, F7-16 and F7-21), which had higher protein and oil levels as compared with Jinda 73.
RESUMO
A drought-resistant soybean cultivar Jinda 70 and a drought-sensitive soybean cultivar Jindou 26 were taken as test materials. At the grain filling stage, the cultivars were subject to three water treatments including sufficient water supply, light drought stress, and severe drought stress by using pot experiments for research on influence of drought on leaf photosynthetic capacity and root growth of soybeans. The results showed that as the degree of drought stress was aggravated, all of the indices including leaf area, chlorophyll content, net photosynthetic rates (Pn), stomatal conductance (g(s)), transpiration rate (Tr), intercellular CO2 concentration (Ci), plant mass, plant height, seed yield, and harvest index in the two cultivars declined. The root length and root mass increased under light drought stress, and decreased under severe drought stress. Root-shoot ratio ascended as the degree of drought stress was aggravated. Under severe drought stress, the increase of root-shoot ratio of the drought-resistant soybean cultivar Jinda 70 was up to 135.7%, which was higher than the that (116.7%) of the drought-sensitive soybean cultivar Jindou 26. Simultaneously, leaf area and chlorophyll content in Jinda 70 were respectively 69.3% and 85.5% of those in the control, which were better than those of Jindou 26. g(s) and Pn of Jinda 70 respectively declined 67.9% and 77.9%, but still lower than those of Jindou 26. Therefore, the decline range of harvest index of Jinda 70 was 43.8%, which was lower than the range of 78.8% of Jindou 26. The Biplot revealed that under different dry treatments, there were significant positive correlations among the six indexes including leaf area, chlorophyll content, Pn, g(s), Tr, and Ci of the two cultivars. There were also significant positive correlations among the six indices including plant mass, plant height, root length, root mass, seed yield, and harvest index. Root-shoot ratio only had significant positive correlation with root mass and had significant negative correlations with other five indices.
