Enjian QIU, Ziquan WEI, Xin ZHONG, Rongping CHEN, Baogang SONG, Chunjun WANG,Zunqiang LI

1. Mudanjiang Tobacco Science Research Institute of Heilongjiang Province Tobacco Corporation, Northeast Agricultural Experiment Station, CNTC,Mudanjiang 157011, China;

2. Huanan Branch of Harbin Tobacco-leaf Corporation, Huanan 154400, China

Longjiang 237, bred based on male sterile lines,is urgently developed to resist tobacco mosaic virus (TMV) in tobacco fields in Heilongjiang[1]. The research detailed and analyzed agronomic characters,characters during growth stage, disease tolerance, economic characters,appearance quality, physical characters, chemical components and sensory quality in order to provide references for development of characteristic highly-qualified tobaccos and rational layout of flue-cured tobacco cultivars in tobaccos fields in Heilongjiang.

Materials and Methods

Test cultivars and sites

The test Variety was Longjiang 237. Specifically, regional tests were conducted in an experimental site of Mudanjiang Tobacco Science Research Institute in 2004, 2010 and 2011. During 2007-2008, the experimental sites were set in Suihua City,Jixian County and Bin County,with the treatment with NC89 as a control. In contrast, production tests were conducted in Zhaozhou County, Suihua City,Ning’an City,and Linkou County,with the treatment with Longjiang No.911 as a control in 2009 and a test was carried out in Ning’an with a treatment with NC89 as a control in 2012.

Test methods

The tests were conducted as per randomized block design, with three replications, and test plots totaled 45-60 m2. Besides, a field contrast experiment was conducted and the areas of different experimental plots tended to be volatile in the range of 1-2 hm2. Additionally, tobaccos fields were managed according to Heilongjiang Tobacco Comprehensive Standard System.

Sampling and detection

During 2010-2011,10 plants were sampled in every test plot for everytobacco Variety,and leaves on the 9th-13thleaf positions were totally collected to send to Zhengzhou Tobacco Research Institute for detection on appearance quality, chemical components and sensory quality. In 2012,100 plants were transplanted of every tobacco cultivar and tobaccos on the 8th-11thpositions and 14th-17thpositions were collected totally,which were also sent to Zhengzhou Tobacco Research Institute for detection on appearance quality, physical characters,chemical components and sensory quality.

Identification methods

Agronomical characters Agronomic characters were measured according to Investigating Methods of Agronomical Character of Tobacco (YC/T142-1998).

Disease tolerance Disease tolerance of tobacco samples was identified according to Identification of Tobacco Cultivar Tolerance of Disease(YC/T2324-2008).

Yield and quality identification After curing, tobacco cultivars were graded as per GB2635-92 and statistical work was made on yield, output value, average price and the proportion of highly-graded tobaccos per unit area.

Appearance quality Appearance quality of samples was identified as per GB2635-92.

Physical characters Physical characters were identified[3].

Chemical components of tobaccos Specifically, total alkaloid, total nitrogen, reducing sugar, total sugar,potassium, chlorine and starch were detected according to YC/T 160-2002,YC/T161-2002,YC/T159-2002,YC/T159-2002, YC/T217-2007, YC/T162-2002 and YC/T216-2007,respectively.

Sensory quality Sensory quality of the samples were detected by experts according to assessment factors on smoking and relevant technology procedures in Quality Detection Center of Zhengzhou Tobacco Research Institute.

Table 1 The results of identification on appearance quality of raw tobaccos

Results and Analysis

Major botanical characters and agronomical characters

On basis of previous testing results in the province, the plant of Longjiang237 is barrel-type; after topping, average plant height reaches 120.62 cm, the number of effective leaf totals 17.9, stem girth is 9.81 cm,internode distance is 6.58 cm, the length and width of Lumbar leaf are 61.84 and 31.84 cm, increasing by 20.57 cm, 0.6 leaves, 0.7, 1.4, 0.85,and 4.17 cm, respectively. The leaf is oval-shape and leaf tip is increasingly sharp;leaf appearance is wrinkled and looks dark green; main veins grow moderately in thickness. Besides,Longjiang237 grows uniformly in fields with strong growth vigor. Furthermore,the growth term after transplanting lasts for about 127 d,which is 6 d later compared with the control. Therefore,it is late ripening. It is tolerant to drought and soil barrenness, and has less demand on nitrogen. From top to down, leaves gradually grow mature and turn yellow. Additionally, it is tolerant to ripeness and it is easy for the cultivar to be cured.

Quality of raw tobaccos

Appearance quality of raw tobaccos According to identification results of Zhengzhou Tobacco Research Institute, the color of middle-part leaves of Longjiang237 were in the range of yellow-golden yellow, and several leaves were greenish. Tobacco maturity was dominated by ripe, supplemented by mature; leaf is dominated by open structure, supplemented by firm structure; tobacco body is dominated bymedium, supplemented by less thin;most tobaccos contain oily, and few contain rich; tobacco color intensity are in the range of moderate-strong.Compared with NC89, Longjiang237 has lightly colored middle-part leaves,moderate body, high-degree maturity,open leaf structure and concentrated color intensity. In general, appearance quality of Longjiang237 performed better compared with NC89(Table 1).

Physical characters of raw tobaccos As shown in Table 2, middlepart leaves and upper-part leaves and the physical characters of Longjiang237 were better compared with NC89[3].

Chemical components of raw tobaccos According to detection results of samples, nicotine of Longjiang Longjiang237 was in the range of 1.39%-2.70% and averaged 1.96%;total nitrogen was in 1.40% -1.80%and averaged 1.55%; reducing sugar was in 25.83%-31.79% and averaged 28.72%;the content of potassium was in 0.73%-1.33%and averaged 1.11%;the content of starch was in the range of 4.21%-6.05%and averaged 4.84%.Compared with NC89, the contents of nicotine, total nitrogen, chlorine and starch maintained lower of middle-part leaves of Longjiang237,but sugar content, reducing sugar-to-nicotine ratio,nitrogen-to-nicotine ratio, and potassium-to-chlorine ratio kept higher;chemical components among tobacco samples tended to be volatile upon growth years. Besides, of upper-part leaves of Longjiang237, nicotine, total nitrogen, and chlorine contents were lower, but reducing sugar-to-nicotine ratio and potassium-to-chlorine ratio were higher compared with the control.The rest indices showed little differences(Table 3).

Table 2 The detection results of physical characters of raw tobaccos

Table 3 The detection results of chemical components of raw tobaccos

Sensory quality of raw tobaccos

As shown in Table 4 and Table 5,tasted sweet, Longjiang237 performed moderately in terms of aroma quality,density, and strength. Besides, it had irritation,and qdor were in the range of medium-slightly heavier;combustibility was from strong to stronger; it was grey to greyish white. Compared with NC89, fragrance style and tastes of Longjiang237 kept similar,but sensory quality of three samples kept lower.

Major economic characters

As shown in Table 6, the yieldof Longjiang237 was in the range of 2 298.00-4 128.60 kg/hm2and averaged 3 011.22 kg/hm2; grade index was in the range of 0.39-0.65 and averaged 0.54; output value index was in the range of 1 122.39-2 350.64 and averaged 1 615.27;high class leaf rate was in 9.55%-36.20%and averaged 20.94%. It can be concluded that Longjiang237 takes advantages in terms of yield, grade index and output value index, which grew by 10.46%, 8.00% and 18.41%, and high class leaf rate was a little higher compared with NC89. As shown in Table 6, major economic characters of Longjiang237 all performed better compared with Longjiang237 in 2009.

Table 4 Smoking assessment on sensory quality of raw tobaccos

Table 5 Identification results of assessment

Disease tolerance

According to artificially induced identification and tolerance assessments, Longjiang237 was immune to TMV,and moderately sensitive to Brown spots, and PVY. In general,the comprehensive tolerance to diseases performed better compared with NC89[1],which is in consistent with survey on diseases in fields.

Discussion

Ecological factors lay foundation for tobacco quality characters and regional characteristics[4-5], playing a key role in tobacco quality and characteristics[4]. Besides, cultivation selection and cultivation are also crucial for tobacco quality[6],of which genotype is an intrinsic factor of genetic expression and cultivation technology has modifying effects on quality formation[4]. Most tobacco fields in Heilongjiang belong to sub-appropriate regions for flue-cured tobacco growth[3], and the tobaccos are most used as stuffing[3,7],which contain higher sugar,and low contents of nicotine,total nitrogen,potassium oxide.It is notable that potassium oxide,chloridion and total nitrogen contents affect smoking quality of tobaccos in Heilongjiang. For example, when the content of potassium oxide is below 1.5% or chloridion content exceeds 0.6%,the smoking quality would decline.Furthermore,the content of total nitrogen should be controlled within 1.8%.In addition, the content of sugar showed none significant correlation with smoking quality of tobaccos. In general, high sugar content, low alkali content, good fragrance quality, low strength and irritation,and low fragrance content make contribution to highly-qualified tobaccos in Heilongjiang used for staffing[7].On the other hand,tobacco industries or enterprises have different demands on fragrance,tobacco quality and grade structure of tobaccos,so that the demands on tobacco cultivars would be diversified. Therefore, the assessment indices of tobacco quality tend to be volatile upon tobacco producing regions. For instance, Shanhai Tobacco has special demands on tobaccos, covering good fragrance quality,fewer miscellaneous gases,lower strength and irritation, and pleasant remaining taste[7].It is necessary for development of highly-qualified and characteristic tobaccos to determine and respect quality demands of tobacco industries to obtain quality orientation by integration of genetic factors, eco-environment and cultivation technology.

Tobacco is a special industrial crop,whose growth,yield,and quality are under influences of fertilization.In general,tobacco yield is increasing upon fertilizer quantity, but tobacco quality would decline by excessive fertilizers[8-9]. Besides,Longjiang237 and NC 89 differ dramatically in terms of fertilizer quantity.For example, quality of Longjiang237 declined when it was fertilized at the quantity the same with NC89. Hence,it is necessary to conduct research on effects of N fertilizers at different quantities on Longjiang237 in tobacco fields in Heilongjiang in order to provide scientific references for rational fertilization of N fertilizers and improving tobacco quality.

Due to small number of sample and significant differences of indices upon years, it is urgent to research appearance quality, physical character,chemical components and sensory quality of Longjiang237.

Table 6 Major economic characters of Longjiang No.237 in Heilongjiang

Conclusions

Longjiang237, immune to TMV,shows stable agricultural economic performance and application, contributed by strong growth vigor, high plant height, sparse internode distance, wide leaf, and good economic traits.

The appearance quality of Longjiang237 is good, and physical traits are proper. The content of K drops significantly, which should be further enhanced. It is moderate aroma type and it feels still sweet for remaining taste. In practice, highlights should be given to aroma quality,odor,strength,irritation,and aftertaste.

Additionally, because of low demands on nitrogen, high tolerance to soil infertility, Longjiang237 is suitable to be grown in fields with moderate or low fertility. In tobacco fields in Heilongjiang, N quantity applied for Longjiang237 reduces by 7.5-15 kg/hm2compared with NC89 and it is necessary to improve the proportion of nitrate nitrogen to about 75% (N∶P∶K of 1∶2∶3).Longjiang237 has a long growth stage after transplanting and turns yellow slowly. Therefore, the cultivar should be covered with ground films and transplanting should be conducted earlier to promote early growth and guarantee growth of upper-part leaves.

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