Responses of assimilation accumulation and distribution and grain yield formation of oilseed flax to crop rotation patterns in dry land.

Rational crop rotation has a positive role in promoting crop production. In order to clarify the effect of different crop rotation patterns and previous crops on growth and grain yield of oilseed flax in dry land flax, a long-term field positioning experiments were conducted. We studied the effect of regulation of six different rotation treatments on grain yield formation of oilseed flax and which response to different stubbles. Six rotation patterns were set as follows: flax-flax-flax-flax (FFFF), flax-wheat-potato-flax (FWPF), flax-potato-flax-wheat (FP-FW), flax-flax-wheat-potato (FFWP), flax-wheat-flax-potato (FWFP) and flax-wheat-potato-wheat (FWPW). The results showed that crop rotation influenced grain yield and yield-related traits of oilseed flax. The grain yield of oilseed flax under different rotation treatments increased by 5.99%-88.49% compared with continuous cropping (FFFF). The frequency of oilseed flax had a significant effect on grain yield. The grain yield under FWPW treatment with 25% flax planting frequency increased by 17.55%-62.50% compared with that of 50% flax planting frequency and 88.49% compared with that of continuous cropping, respectively. Plant height, capsule number, branch number and 1000-seed weight under rotation treatments were greater 1.74%-15.15%, 12.82%-38.48%, 11.02%- 24.93% and 4.88%-13.56% than that of FFFF pattern, respectively. The accumulation amount and distribution ratio of dry matter in different organs were significantly correlated with grain yield of oilseed flax. Crop rotation significantly promoted dry matter accumulation, which were increased by 14.87%-39.57% compared with that of FFFF. The dry matter accumulation was decreased with the increasing of frequency of oilseed flax, which was generally expressed as 25% flax planting frequency > 50% flax planting frequency > 100% flax planting frequency. The results showed that crop rotation could effectively promote plant height, branch number, effective capsule number or 1000- grain weight by promoting the accumulation of dry matter in various organs of flax and optimizing dry matter distribution, which further increased grain yield of oilseed flax. It indicates that appropriate rotation mode and crop stubble can effectively solve the problem of yield reduction caused by continuous cropping of flax. In this study, FWPW rotation mode is the best rotation mode for high yield of flax in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]