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Institute of Crops, Anhui Academy of Agricultural Sciences/Hefei Branch, National Wheat Improvement Center, Hefei 230031, China

AbstractIn order to clarify the status of grain quality in the main wheat production areas of Anhui Province, wheat quality sampling and testing were carried out in the main wheat production areas of Anhui Province in 2015, 26 cultivars and 62 samples were collected, and grain traits, quality indexes and quality traits were analyzed and evaluated. The average bulk density of the sample was 796 g/L; the average hardness index was 49.2; the average 1 000-grain weight was 41.6 g; the average grain moisture content was 11.8%; the average crude protein content was 11.7%; the average wet gluten content was 31.1%; the average Zeleny sedimentation value was 24 mL; the average water absorption was 54.9%; the average stability time was 5.6 min. The crude protein content of 35.5% samples reached the standard of high quality weak gluten; the wet gluten content of 40.3% samples was above the second grade of high quality strong gluten; the falling number of 83.9% of the samples reached the national standard of high quality wheat; the stability time of 27.4% of the samples reached higher than the second grade of high quality gluten, and the stability time of 17.7% samples reached the standard of high quality weak gluten wheat.

Key wordsWheat, Anhui Province, Grain quality

1 Introduction

Wheat is one of the main food crops in China, and the grain quality of wheat has an important influence on flour and its deep processing[1]. Influenced by genotype, cultivation measure, ecological environment, such as soil type, temperature and precipitation, the grain quality traits of wheat vary greatly in different regions[2-7]. Wheat is the most important cereal crop in Anhui Province. Under the guidance of the policies of the Party Central Committee, the State Council, and the provincial government, the wheat industry in Anhui Province has developed steadily and healthily in recent years. The area, unit yield and total output of wheat continue to maintain the third-fifth place in the main wheat producing provinces of China, which has made important contribution to the national food security. In order to know the situation of wheat quality in Anhui Province, improve the market competitiveness and serve the government decision, Institute of Crops of Anhui Academy of Agricultural Sciences carried out the sampling and testing of wheat in the main producing areas of wheat in Anhui Province in 2015. A total of 62 samples were received, and the grain traits, quality indexes and quality traits were analyzed and evaluated.

2 Materials and methods

2.1 Test design

The cultivars with large planting area and high yield potential were selected as samples from the relevant counties (cities and districts), and the sampling work was carried out in accordance with the requirements ofWheatSamplingOperationRulesin2015 formulated by the Ministry of Agriculture. Eight kilograms of grains were taken as samples for examination, involving 23 counties (cities, districts) (Guzhen County, Wuhe County, Lixin County, Mengcheng County, Qiaocheng District, Guoyang County, Dingyuan County, Fengyang County, Mingguang County, Funan County, Linquan County, Yingdong District, Yingzhou District, Changfeng County, Suixi County, Panji District, Jin’an District, Shouxian County, Dangshan County, Lingbi County, Sixian County, Xiao County, Yongqiao District), and 26 wheat cultivars (Jimai 22, Huaimai 22, Liangxing 66, Liangxing 99, Shannong 17, Shannong 20, Huaimai 29, Yannong 19, Yannong 5158, Wanmai 52, Luomai 23, Fanmai 5, Gushen 6, Huacheng 3366, Annong 0711, Huaimai 28, Huaimai 33, Huaimai 35, Lunxuan 22, Sumai 9, Weilai 0818, Xinmai 21, Yannong 5286, Yangmai 13, Zhongmai 895, Zimai 19).

2.2 Test items and methods

62 samples were tested in accordance with the inspection methods prescribed by the national standards. Upon receipt of the samples, they were dried and cleaned timely (moisture content controlled at 11%-13%), and the chaff, broken grains and other impurities were removed. Weighing method (50 g) was used to measure unsound kernels. The 1 000-grain weight of the sample was measured and manually counted. GHCS-1000 wheat-maize capacity apparatus was used to measure the grain volume weight. The moisture and crude protein (dry base) of samples were analyzed by FOSS (Sweden) 1241 near infrared grain analyzer. The hardness index was determined by SKCS4100 single grain tester of Perten Company. According to the type of grain hardness, the moisture content of soft wheat and mixed wheat was adjusted to 14.0%-14.5% and that of hard wheat to 15.0%-15.5% by a certain amount of deionized water for 18 h infiltration. Wheat flour was milled with a German Brabender Junior small-scale experimental mill. The rate of flour yield was about 60%. After being sifted by 80 mesh sieve, the flour was mixed and kept in a sealed plastic bag and stored in the shade. The Zeleny sedimentation value of flour was measured by Brabender sedimentation meter. The falling number of flour was measured by Perten FN1900 falling number tester. The content of wet gluten was determined by GM2200 gluten determination system of Perten Company. The properties of flour (water absorption, formation time, stabilization time, weakening degree, quality index) were tested by Brabender 810108 powder tester.

3 Results and analysis

3.1 Grain quality traits

In 2015, the range of volume weight of samples for testing was 721-842 g/L with an average of 796 g/L. 39 samples with volume weight above first grade (≥790 g/L) accounted for 62.9% of the total samples; 16 samples with volume weight above second grade (≥770 g/L-﹤790 g/L) accounted for 25.8% of the total samples; three samples with volume weight above third grade (≥750 g/L-﹤770 g/L) accounted for 4.8% of the total samples; four samples with volume weight of the fourth grade and below accounted for 6.5% of the total samples. The hardness index ranged from 9.7 to 73.5 with an average of 49.2. The hardness index reached the standard of hard wheat (hardness index≥60) in 26 samples, accounting for 41.9% of the total samples; the hardness index reached the standard of mixed wheat (hardness index=40-60) in 14 samples; the hardness index reached the standard of soft wheat (hardness index<40) in 22 samples. The variation range of unsound kernel rate was 0.6%-21.3%, with an average of 6.3. There were 38 samples with the unsound kernel rate of ≤6.0%, accounting for 61.3% of the total samples; there were 7 samples with the unsound kernel rate of ≥10.0%, accounting for 11.3% of the total samples. The variation range of 1 000-grain weight was 31.8-51.2 g with an average of 41.6 g. The moisture content of grains varied from 10.7% to 13.0%, with an average of 11.8% (Table 1).

Table 1 Comprehensive quality index for samples

3.2 Intrinsic quality index

In 2015, the crude protein content of test samples varied from 11.0% to 13.0%, with an average of 11.7%. There were 40 common wheat samples (11.5%﹤crude protein content﹤14%), accounting for 64.5% of the total samples; there were 22 weak gluten wheat samples (crude protein content≤11.5%), accounting for 35.5% of the total samples. The content of wet gluten varied from 18.7% to 58.2% with an average of 31.1%. 18 samples with wet gluten content up to the first grade of strong gluten wheat (wet gluten content≥35.0%) accounted for 29.0% of the total samples; seven samples with wet gluten content up to the second grade (32.0%≤wet gluten content﹤35.0%) accounted for 11.3% of the total samples; 35 common wheat samples (22.0%≤wet gluten content﹤32.0%) accounted for 56.5% of the total samples; two weak gluten wheat samples (wet gluten content≤22.0%) accounted for 3.2% of the total samples. There were 10 samples with the falling number<300 s, with an average of 253 s; there were 52 samples meeting the national standard for high quality wheat (falling number≥300 s), accounting for 83.9% of the total samples. The Zeleny sedimentation value varied from 18 to 29 mL with an average of 24 mL.

3.3 Farinographical properties

In 2015, the variation range of water absorption rate was 45.3%-60.4%, with an average of 54.9%. The range of formation time was 1.0-20.0 min with an average of 3.3 min. The range of weakening degree was 3-196 FU, and the average value was 64 FU. The quality index ranged from 20 to 158, with an average of 60. The variation range of stabilization time was 1.1-14.6 min, and the average value was 5.6 min. There were seven samples with the dough stabilization time reaching the first grade of strong gluten wheat (dough stabilization time≥10.0 min), which accounted for 11.3% of the total samples; there were 10 samples with the dough stabilization time reaching the second grade of strong gluten wheat (7.0 min≤dough stabilization time﹤10.0 min), which accounted for 16.1% of the total samples; there were 34 samples of common wheat (2.5 min﹤dough stabilization time﹤7.0 min), accounting for 54.8% of the total samples; there were 11 samples reaching the grade of weak gluten wheat (dough stabilization time≤2.5 min), which accounted for 17.7% of the total samples.

3.4 Average quality index of samples from different areas

The average quality index of samples from different areas is shown in Table 2.

3.4.1Volume weight. The average volume weight of samples from Mengcheng County, Linquan County, Panji District, Wuhe County, Lixin County, Shouxian County, Changfeng County, Guzhen County, Yingdong District, Yingzhou District, Qiaocheng District, Mingguang County, Guoyang County, Xiaoxian County, Dangshan County and Suixi County reached the first grade standard. The average volume weight of samples from Sixian County, Jin’an District, Lingbi County, Yongqiao District, Fengyang County and Dingyuan County reached the second-grade standard. The average volume weight of samples from Funan County reached the third grade standard.

3.4.2Hardness. The average hardness index of the samples submitted for examination from Yongqiao District, Shouxian County, Dangshan County, Suixi County, Wuhe County and Xiaoxian County reached the hard standard. The average hardness index of samples from Funan County, Yingdong District, Yingzhou District and Changfeng County reached the soft standard. The average hardness index of the samples sent for examination from other areas was of mixed type.

3.4.3Crude protein content. None of the samples submitted for examination from all regions had the average crude protein content meeting the standard of high quality strong gluten. The average crude protein content of samples submitted for examination from Xiaoxian County, Dangshan County, Yingdong District, Mengcheng County, Lixin County and Wuhe County reached the standard of weak gluten wheat.

3.4.4Wet gluten content. The average content of wet gluten in samples sent for examination was high in Xiaoxian County, Fengyang County, Guoyang County and Suixi County, exceeding 35.0%, which reached the first grade standard of strong gluten. The average content of wet gluten in samples sent for examination from Sixian County, Linquan County, Guzhen County, Changfeng County, Qiaocheng District, Yongqiao District and Dangshan County reached the second grade standard of strong gluten. The average wet gluten content in samples sent for examination from Shouxian County reached the weak gluten standard.

3.4.5Dough stabilization time. The average dough stabilization time of samples sent for examination from Yongqiao District, Linquan County, Yingzhou District, Wuhe County and Yingdong District was more than 7.0 min, which reached the standard of high quality strong gluten wheat. The average stabilization time of the samples from Funan County and Mingguang County was less than 2.5 min, which reached the quality standard of weak gluten wheat.

3.4.6Falling number. Among all test samples, some samples sent for examination from Guzhen County, Dingyuan County, Mengcheng County, Lixin County, Shouxian County, Lingbi County, Linquan County, Wuhe County, Funan County had the falling number of less than 300 s, while the other areas generally reached the national standard of high quality wheat (falling number≥300 s).

3.4.7unsound kernels. The average unsound kernel rate of samples was less than 6.0% in Xiaoxian County, Jin’an District, Dangshan County, Suixi County, Fengyang County, Mingguang County, Guoyang County, Qiaocheng District, Yingzhou District, Shouxian County, Sixian County, Panji District, Yongqiao District and Wuhe County. This index reached the national quality wheat purchasing standard; the average unsound kernel rate of samples from Dingyuan County, Funan County and Changfeng County was more than 10.0%, which did not meet the national minimum price collection and storage standard.

3.5 Comparison of single index of different wheat cultivars

The statistics of average quality indexes of different cultivars of wheat are shown in Table 3.

3.5.1Volume weight. By comparing the volume weight of different wheat cultivars, 17 cultivars reached the first grade wheat standard, accounting for 65.4% of all cultivars, which were Huaimai 33, Shannong 17, Fanmai 5, Huaimai 22, Huacheng 3366, Xinmai 21, Zimai 19, Huaimai 35, Yannong 5286, Lunxuan 22, Shannong 20, Liangxing 66, Luomai 23, Gushen 6, Weilai 0818, Liangxing 99, and Zhongmai 895. seven cultivars reached the second grade, accounting for 26.9% of all cultivars, namely Yangmai 13, Sumai 9, Yannong 19, Yannong 5158, Huaimai 28, Annong 0711 and Jimai 22. Wanmai 52 and Huaimai 29 reached the third grade standard.

3.5.2Hardness. By comparing the hardness index of different wheat cultivars, the average hardness index of nine cultivars (Wanmai 52, Liangxing 66, Shannong 20, Yanmai 19, Huaimai 33, Jimai 22, Liangxing 99, Shannong 17 and Lunxuan 22) was higher than 60, and they were hard wheat. The average hardness index of 10 cultivars (Zimai 19, Huaimai 22, Huaimai 35, Luomai 23, Yannong 5158, Weilai 0818, Xinmai 21, Huaimai 28, Fanmai 5, Huaimai 29) was smaller than 40, and they were soft wheat; the rest of cultivars were mixed wheat.

3.5.3Crude protein content. By comparing the crude protein content of different wheat cultivars, the crude protein content of eight cultivars (Yannong 5286, Shannong 20, Yangmai 13, Huaimai 35, Gushen 6, Wanmai 52, Liangxing 66, Lunxuan 22) reached the weak gluten wheat standard, and the other 18 cultivars reached the common standard, accounting for 69.2% of the total samples.

3.5.4Wet gluten content. By comparing the wet gluten content of different wheat cultivars, the average wet gluten content of six cultivars (Zimai 19, Jimai 22, Zhongmai 895, Liangxing 66, Liangxing 99, Gushen 6) in different areas reached the first grade of strong gluten wheat, accounting for 23.1% of the total cultivars. Five cultivars (Luomai 23, Xinmai 21, Wanmai 52, Weilai 0818, Shannong 20) reached the second grade of strong gluten, accounting for 19.2% of all cultivars. Lunxuan 22 reached the standard of high quality weak gluten wheat. The wet gluten content of the other 19 cultivars could not reach the standard of high quality wheat, accounting for 73.1% of the total cultivars.

3.5.5Dough stabilization time. By comparing the stabilization time of different cultivars of wheat dough, the dough stabilization time of two cultivars Huacheng 336 and Huaimai 28, reached the first grade of strong gluten, accounting for 7.7% of the total number of cultivars. four cultivars (Yannong 5286, Shannong 20, Huaimai 22, Fanmai 5) reached the second grade of strong gluten, accounting for 15.7% of the total cultivars. There cultivars (Lunxuan 22, Luomai 23, Wanmai 52) reached the standard of high quality weak gluten wheat, accounting for 1.2% of all cultivars. The other 17 cultivars could not reach the standard of high quality wheat, accounting for 65.4% of the total cultivars.

3.5.6Falling number. By comparing the falling number of different cultivars of wheat, the falling number of eight cultivars (Lunxuan 22, Wanmai 52, Liangxing 99, Huaimai 29, Yannong 19, Shannong 17, Jimai 22, Yannong 5158) was smaller than 300 s in some test points, while the falling number of the other 18 cultivars reached the standard of high quality wheat.

3.5.7unsound kernels. The unsound kernel rate of 15 cultivars (Yangmai 13, Sumai 9, Huaimai 35, Shannong 20, Huaimai 28, Liangxing 99, Lunxuan 22, Luomai 23, Liangxing 66, Annong 0711, Gushen 6, Huaimai 22, Zimai 19, Weilai 0818, Huacheng 3366) was lower than 6.0%, and the unsound kernel rate of two cultivars (Wanmai 52, Xinmai 21) was higher than 10.0%.

Table 2 Average quality index of samples from different areas

Table 3 Average quality index of different cultivars of wheat

4 Discussions

4.1 Overall evaluation

In 2015, 62 wheat samples were collected from the main wheat producing areas in Anhui Province, involving 23 counties (cities, districts) and 26 wheat varieties, including Jimai 22, Huaimai 22, Liangxing 66, Liangxing 99, Shannong 17, Shannong 20, Huaimai 29, Yannong 19, Yannong 5158, Wanmai 52, Luomai 23, Fanmai 5, Gushen 6, Huacheng 3366, Annong 0711, Huaimai 28, Huaimai 33, Huaimai 35, Lunxuan 22, Sumai 9, Weilai 0818, Xinmai 21, Yannong 5286, Yangmai 13, Zhongmai 895, and Zimai 19. In 2015, the average volume weight of samples from Anhui Province for examination in 2015 was 796 g/L; the average hardness index was 49.2; the average 1 000-grain weight was 41.6 g; the average moisture content of grain was 11.8%; the average crude protein content was 11.7%; the average wet gluten content was 31.1%; the average Zeleny sedimentation value was 24 mL; the average water absorption rate was 54.9%; the average dough formation time was 3.3 min; the average stabilization time was 5.6 min; the average weakening degree was 64 FU. The crude protein content of 35.5% samples reached the standard of high quality weak gluten; the wet gluten content of 40.3% samples was above the second grade of high quality strong gluten; the falling number of 83.9% samples reached the national standard of high quality wheat; the stabilization time of 27.4% samples reached higher than the second grade of high quality strong gluten; the stabilization time of 17.7% samples reached the standard of high quality weak gluten wheat.

4.2 Analysis of factors affecting quality

4.2.1Meteorological factors. In 2015, the wheat production in Anhui Province roughly experienced the meteorological process of "warm winter drought-late spring coldness in heading and jointing period-insufficient sunshine in grain filling period-more rainy days in later growth period", and the production showed a general stable trend, but there were many hidden dangers. According to the statistics, the average number of sunshine hours in May 2015 was 126, 64 less than normal, which was the least since 2003. It was very disadvantageous to the accumulation of protein. Therefore, the crude protein content of the sample in this year was obviously low, and none of the samples reached the standard of high quality strong gluten. However, the temperature difference between the morning and the evening in the grain filling period was large, and the 1 000-grain weight of grain was a little higher than that of previous years. In the harvest period of wheat along the Huaihe River, the torrential rains and wheat scab and other diseases occurred more seriously in some regions. The overlapping of unfavorable factors resulted in the problem of unsound kernels, and the falling number of 10 samples did not reach the high quality standard.

4.2.2Cultivar factors. The samples were from the main demonstration wheat production areas, and the cultivars involved were the main types or had large planting area in Anhui Province. The following 6 cultivars, Jimai 22, Huaimai 22, Huaimai 29, Shannong 20, Shannong 17 and Yannong 19, were taken as examples for further explanation.

(i) Eight samples of Jimai 22 collected were distributed in Guzhen County, Mengcheng County, Qiaocheng District, Guoyang County, Linquan County, Xiaoxian County, Yongqiao District in the wheat production areas along Huaihe River or in the north of Huaihe River. In Linquan and Guzhen counties, the falling number of this cultivar was not up to the standard, the rate of unsound kernels was more than 10.0%, the sprouting of ear was serious and the cultivar was hard. Except for Qiaocheng District, Guoyang County, Linquan County, Xiaoxian County, Yongqiao District, where the wet gluten content reached the standard of high quality strong gluten wheat, the quality indexes of other regions were all at medium level compared with other cultivars. (ii) Seven samples of Huaimai 22 collected were distributed in Lixin County, Qiaocheng District, Guoyang County, Linquan County, Yingdong District, Yingzhou District, Lingbi County in the wheat production areas along Huaihe River or in the north of Huaihe River. The cultivar was soft, the average volume weight was 800 g/L for all regions, and the stabilization time of this cultivar for examination from Guoyang County, Qiaocheng District and Yingdong District was over 10 min. Four samples of Huaimai 29 collected were from Lixin County, Funan County, Fengyang County and Sixian County in the wheat production areas along Huaihe River or in the north of Huaihe River. The difference of grain hardness of the cultivars was large among different regions, and the sampling results of Funan County showed that the unsound kernel rate reached 19.2% and the falling number was not up to the standard. The average 1 000-grain weight was high, reaching 43.1 g. The volume weight and other indexes were average. (iii) Four samples of Shannong 17 collected were distributed in Wuhe County, Mengcheng County, Mingguang County and Yongqiao District in the wheat production areas along Huaihe River or in the north of Huaihe River. The cultivar was hard, and the falling number of cultivars from Wuhe County for examination was below the standard; the cultivar stabilization time was different in different regions, it was more than 9 min in Wuhe County and Yongqiao District, and fewer than 2.5 min in Mengcheng County and Yongqiao District. Four samples of Shannong collected were distributed in Guzhen County, Dangshan County, Sixian County and Yongqiao District. The cultivar was hard, the 1 000-grain weight and volume weight of the cultivars were great, with an average of 46.5 g and 812 g/L for all regions. The water absorption rate was high, 58.3% on average. The stabilization time of this cultivar for examination from Sixian County and Yongqiao District in Suzhou City was long, both exceeding 7 min. (iv) Four samples of Yannong 19 collected were distributed in Yongqiao District, Wuhe County, Dingyuan County and Panji District. The cultivar was hard, the falling number of samples from Dingyuan County for examination was not up to the standard, and the unsound kernel rate exceeded the standard seriously, reaching 21.3%. The remaining indexes were at the medium level.