Abstract:

【Objective】As the material of making biscuits and cakes, the baking properties of soft wheat flour is determined by its content and quality of protein. The grain protein content (GPC, %) is not only determined by genetic factors, but also affected by environment and farming practices. In order to provide suggestions for quality region classification for the soft wheat areas in Jiangsu province, this paper explored the suitable planting areas and influencing factors of soft wheat.【Method】Based on the two-year investigation data related to wheat quality in Jiangsu province, the random forest algorithm was used to screen important indicators, and the meta-analysis of proportions was employed to analyze the impacts of geolocation and meteorological factors on the possibility of wheat GPC reaching the standard of soft wheat under the ordinary farming practices. 【Result】 The average of two-year wheat GPC was 13.92%. In 2018, GPC ranged from 11.06% to 18.09% and the average value was 14.52%, in which GPC of 10% samples was lower than 12.5%. In 2019, the range of GPC was 10.20%-16.50% and the average value was 13.33%, in which GPC of 29.71% samples was lower than 12.5%. With application of random forest algorithm and meta-analysis, it was found that the GPC of wheat growing in the southeastern part along sea and lake of Jiangsu was most likely to meet the standard of soft wheat, and the possibility of which was 92%, followed by the northwestern part along river and the eastern coastal area in Jiangsu. When the plantation was 20-30 km away from the primary river and lake or coastline, the probability of reaching the standard was relatively high, which was 23.95%. In terms of meteorological factors, precipitation had the greatest influence on the formation of soft wheat in Jiangsu province during the early growth stage, especially at emergence stage and joining stage. The impact of accumulated temperature was more important during the later stage of growth stage, especially during grain filling stage and flowering stage. In addition, the sunshine hours at emergence stage and jointing stage and the precipitation at flowering stage were also more important for the formation of soft wheat in Jiangsu province. Among them, the precipitation at emergence stage was positively correlated with the possibility of wheat GPC reaching the standard of soft wheat in Jiangsu province. However, the sunshine hours during emergence stage, the precipitation and the sunshine hours during jointing stage, and the accumulated temperature during filling stage were opposite. 【Conclusion】 The suitable planting areas for soft gluten wheat in Jiangsu province were mainly concentrated in the eastern coastal areas and southeastern coastal and lake areas. With suitable precipitation during the emergence and jointing period and accumulated temperature during flowering and filling stage, the northwest areas along the river would also have high possibility to produce soft wheat. Thus, the geographic location (distribution of river systems, etc.) and climate should be considered when zoning the suitable planting areas for different quality types of wheat.

Key words: soft wheat, grain protein content, meta-analysis of proportions, random forest