武陵山区不同播期及密度对早熟油菜农艺性状和产量品质性状的影响OA

To identify the optimal sowing date and density for early-maturing varieties of Brassica napus under late-sowing conditions in the Wuling Mountain area,this study established three different sowing date and density treatments to investigate their effects on the agronomic traits,frost resistance,and yields of three early-maturing varieties of B.napus.The results showed that with the delay of sowing date and the increase in sowing density,both the number of green leaves and the total number of leaves per plant decreased significantly,with notable differences among varieties.Among the three varieties,A3 exhibited the lowest number of leaves across all the treatments.Leaf length and leaf width were both the highest under B1 treatment and the lowest under B3 treatment.In terms of root crown diameter,varieties A1 and A2 performed best under treatment B1,while the root crown diameter of variety A3 showed a significant reduction with the delay of sowing date and the increase in sowing density.All the varieties achieved the highest yield under B2 treatment and the lowest yield under B3 treatment.Furthermore,delayed sowing and increased sowing density aggravated frost damage,resulting in higher frost damage index.Considering plant height,branching characteristics,and yield performance,the treatment combinations A1B1 and A2B2 were superior.Particularly,A2B2 not only achieved high yield but also enhanced oil content,thus being recommended as the optimal cultivation practice for late-sown B.napus in the Wuling Mountain area.