关键词: 油菜, 根系, 碳、氮积累, 干物质分配, 产量

Abstract:

【Objective】 The crop yield is significantly affected by the ecological environment. In this study, the yield formation mechanism of winter rapeseed (Brassica napus L.) under different climatic conditions was studied to provide a theoretical basis for the high-yield breeding and cultivation of winter rapeseed. 【Method】The three different varieties of winter rapeseed were selected, including high-yield rapeseed (Qinyou 1618, Q1618), rapeseed materials (QF1), and conventional rapeseed (Zhongshuang 11, ZS11). Field experiments were conducted in the Huanghuai region (Yongshou, Shaanxi) and the middle reaches of the Yangtze River (Yangluo, Hubei) from 2020 to 2021 to study the characteristics of growth, development and physiological characteristics of the three different varieties of winter rapeseed in different ecological regions. 【Result】Different ecological regions significantly affected the root growth, dry matter accumulation and distribution, carbon and nitrogen metabolism response characteristics of winter rapeseed. The root growth of Q1618 was the most vigorous at the two sites, and its root length increased by 21.0% and 6.0% on average compared with ZS11 and QF1 during the overwintering period, respectively. In addition, the spatial distribution differences of root systems among the three varieties at the flowering stage were mainly concentrated in the shallow soil (0-15 cm) at Yangluo, while they were mainly concentrated in the deep soil (15-30 cm) at Yongshou. Compared with ZS11 and QF1, Q1618 showed an average increase of 138.1%, 78.8%, 24.2%, 83.3%, and 104.8%, 103.1%, 44.2%, 41.6% in root length, root surface area, root diameter, and root tip number of deep soil layer during flowering stage at the two sites, respectively. The root growth and yield of rapeseed during overwintering and flowering period were significantly positively correlated, and the correlation was stronger at Yongshou. During the overwintering period of rapeseed in the Huanghuai region, the dry matter accumulation in the aboveground parts slowed down, and the nitrogen content in the leaves was decreased, the soluble sugar content in roots were accumulated, and the sucrose and fructose content in various organs (roots, stems, and leaves) with the overall performance being QF1>Q1618>ZS11, and the soluble sugar content in all organs in this area was positively correlated with yield. The roots, stems and leaves of winter rapeseed in the middle reaches of Yangtze River were basically in a synchronous growth stage, and the dry matter accumulation during the overwintering period was 3.0 times higher than that in the Huanghuai region, and the dry matter accumulation during the overwintering period was significantly positively correlated with the effective pod number per plant in this area. After the bolting stage, the dry matter accumulation of Q1618 was the highest at the two sites. The dry matter accumulation of winter rapeseed at maturity and the dry matter distribution ratio were significantly increased by 10.3% and 39.0% at Yongshou, compared with that at Yangluo site, respectively. On the whole, although the effective number of pods per plant was increased in the middle reaches of the Yangtze River, the measured of winter rapeseed (except ZS11 which was reduced by freezing damage) increased by 21.1% on average by increasing the number of grains per pod and the 1000-grain weight in the Huanghuai region compared with that in the middle reaches of the Yangtze River. Correlation analysis also showed that the rapeseed yield at Yongshou site was significantly positively correlated with the seed number per pod and the 1000-grain weight, while the yield of rapeseed at Yangluo site was significantly positively correlated with the effective number of pods per plant【Conclusion】 The effective number of pod per plant was increased by promoting the growth of rapeseed before the overwintering period in the middle reaches of the Yangtze River. However, in the Huanghuai region, the vegetative growth of aboveground plants during the overwintering period was properly controlled, and the dry matter of roots and stems was promoted to be distributed to grains after bolting, and the number of grains per corner and 1000-grain weight were increased, which was conducive to achieving high yield of winter rapeseed.

Key words: rapeseed (Brassica napus L.), root system, carbon and nitrogen accumulation, dry matter distribution, yield