Estimation of seed yield in oilseed rape to identify the potential of semi-resynthesized parents for the development of new hybrid cultivars

Enhancing yield and oil content in oilseed rape hybrids: Insights from line × tester and SIIG approaches

Background

The production of high-oil-yielding hybrid varieties is a primary objective in oilseed rape (Brassica napus L.) breeding programs. Biometric genetic experiments such as line × tester provide valuable insights into the genetic structure of traits associated with high oil yield.

Methods

In this study, 21 winter hybrids of oilseed rape were evaluated, which were generated by crossing three restorers with seven CMS lines. The experiment was conducted using a line × tester experiment based on a completely randomized block design. Phenological, agronomic, yield, and oil yield components were assessed in this study. The ideal genotype selection index (SIIG) methodology was also employed to identify superior hybrids based on all studied traits simultaneously.

Results

Significant differences were observed between the obtained hybrids and the check cultivars. Heritability analysis revealed that phenological traits were primarily controlled by additive effects, while agronomic and qualitative traits were mainly influenced by non-additive gene effects. Both broad-sense and narrow-sense heritability exhibited a wide range, underscoring the importance of genetic variance. Notably, the hybrids T1 × L5, T1 × L6, and T3 × L1 showed significant specific combining ability values of 394.74, 541.73, and 1236.79, respectively, making them the top specific combinations for increasing seed yield. Based on the SIIG index, hybrids T3 × L1, T1 × L5, T1 × L3, and T2 × L3 emerged as high-oil-yielding hybrids with desirable agronomic traits.

Conclusions

The identified superior hybrids by line × tester and SIIG approaches hold promise for the development of high-yielding oilseed rape cultivars with desirable agronomic traits in oilseed rape breeding programs.

Design and experiment of a shovel-tooth removal end-effector for abnormal plants in hybrid rape breeding based on MBD-DEM coupling

In view of the problem that removing abnormal plants in breeding rape requires a large amount of labor and is inefficient, combined with the planting requirements of breeding rape, a shovel-tooth end-effector was designed, and a shovel-tooth removal test bench was built. A simulation model based on MBD (Multibody Dynamics)-DEM (Discrete Element Method) coupling was constructed. Then we conducted a Box-Behnken test with four factors and three levels. Taking the angle of soil penetration, speed of soil penetration, depth of soil penetration and speed of shovel-tooth gathering as the test factors, the soil penetration force and shovel-tooth gathering force as the test indicators. The mathematical regression model between test indicators and test factor was established. After optimizing the parameters of the model, the best combination of parameters with low soil penetration force and low shovel-tooth gathering force was obtained: angle of soil penetration of 84°, speed of soil penetration of 9 cm/s, depth of soil penetration of 8cm, and speed of shovel-tooth gathering of 6 cm/s. The simulation model was validated by field experiments. The average soil penetration force and average shovel-tooth gathering force of the three groups of pull-out tests were 34.8 N and 763.0 N, respectively. The removal rates were 96%, 92%, and 94%, all greater than 90%, indicating that the removal effect of the shovel-tooth end-effector was good, and the parameters were reasonably designed. The results can serve as reference for the design of rape abnormal plants removal device and the operation of MBD-DEM coupling simulation end-effector.