Evaluation and characterization of bidi and natu Tobacco (Nicotiana tabacum) germplasm lines

Introduction

Tobacco (Nicotiana tabacum L.) 2n=48, is majorly cultivated as commercial and medicinal crop worldwide (Flavell et al. 1992) [2] . The crop is commercially harvested for its leaf, further processes for human use. Worldwide, 5.8 mt of tobacco produced during 2022, while India is the second largest producer of tobacco crop following China. Different types of tobacco are growing in different states, covering 0.45 mha of area. According IBEF, 2025, in India, Andhra Pradesh is the largest producing state of tobacco, which is accounting almost 20% of production with 0.2 mt during 2023-24. Tobacco crop is commercial crop as it is contributing towards employment to millions of people like farmers and workers during processing and marketing also. To meet the stability in increasing demand, it is very essential to improve quality and yield. To develop the best genotypes, gaining knowledge on variation and diversity in the present available germplasm is very crucial. Based on the characterization of available germplasm lines, breeder can observe the variation present in characters and can identify the better parents to be utilized in further breeding programmes.

Materials and Methods

This trial was conducted with the available germplasm at Regional Agricultural Research Station (RARS), Nandyal of Acharya NG Ranga Agricultural University, Andhra Pradesh during 2022-23 for DUS characterization. The experiment was sown in augmented design with two local checks. Each genotype was sown in four rows with a spacing of 75 x 75 cm between rows and plants respectively. Observations recorded for twenty nine characters on 10 plants per genotype and mean of 10 plants were taken up. To assess the DUS characters, optimum plant growth stages were examined for the respected traits.

Results

Germplasm of any crop will be descripted by characterization, which determine the expression of heritable traits of either agronomic or morphological features (Namrata Dhirhi et al., 2016) [7] . Hence, this is very important to provide the detailed information on different characters of distinctness (D), uniformity (U) and stability (S) for their effective utilization in the further crop improvement programmes. Once, the germplasm is characterized, it is very easy to analyse the diversity between lines for the desirable traits to be improved and can also possible for further use in breeding programmes to generate highly adaptable varieties with broad genetic base. In this study, out of 71 germplasm lines, 53 bidi and 18 natu tobacco lines were assessed, which were taken from All India Network Project on Tobacco at RARS, Nandyal. All protection measures were taken up during the crop season, off types were rogued out and the data on characters were recorded in germplasm lines at their different growth stages. All accessions showed remarkable variation within them for recorded characters.  Plant characteristics: Characters were noted on matured tobacco plants ( were ranged from 20 cm to 75 cm. In middle of plant, the leaf length is varied from 31 cm to 80 cm whereas, at the top of plant, it ranges between 23 cm to 66 cm.  Leaf width (cm): Leaf width also, at the bottom of plant were ranged from 14 cm to 33 cm. In middle of plant, the leaf width is varied from 15 cm to 37 cm whereas, at the top of plant, it ranges between 10 cm and 22 cm. Total of leaves: Total no. of leaves ranged between 16 to 40. 94% of lines (67) were having >18 leaves.  Economic number of leaves: Economic number of leaves ranged between 12 to 22. 85% of lines (61) were having >18 leaves.  Spangling: It is visual trait of leaf and indicator of quality which can be observed as the brick red rusty spots/patches on the leaf surface. It is also can be described as wrinkling or puckering of leaf. It is medium in all germplasm lines at its maturity stage.

Flower characteristics:

Data was recorded at the time of flowering (Table 1).  Days to first flowering: Days to first flowering in all studied germplasm lines ranged between 105 to 130 days.  Days to 50% flowering: It ranges from 120 to 158 days.

Discussion

A range of characters were evaluated in seventy-one bidi and natu tobacco germplasm lines maintained at RARS, Nandyal during 2022-23. Lot of diversity towards plant, leaf and flower characters was found and it is very essential to meet the objectives of present plant breeding programmes including the improvement of leaf yield, leaf quality, adaptability and resistance to biotic and abiotic stresses. Detailed information on range and nature of different characteristic will help to formulate the programmes to target multi trait selection and also provides knowledge on identification of natural diverse group of genotypes. Further it is very helpful to explore new sources of genes for tobacco improvement. Mostafa Mehdizadeh, et al. (2023) [6] , Rajan and Bhat (2022) [8] , Choudhary and Datta (2021) [1 ], Lakshmanan and Jayaraman (2018) [4] , Baghyalakshmi et al.

(2018) [3] and Singh et al. (2016) [9] and also reported wide variation in the characteristics of germplasm material of tobacco.

In conclusion, among all studied characteristics, most of the germplasm lines showed desirable characters like semi erect type of plant growth habit, medium plant height (100-160 cm), medium internodal length (3-4 cm), light green coloured stems, green coloured upright position of leaves with lanceolate shape, puckered surface, acute base and tip, thick midribs, wavy margins and frilled auricle development in matured leaves. Maximum lines are having branched inflorescence and pink flowers with fluted corolla type. Minimum no. of germplasm lines showed the other classes of characters indicates different genes interacts for development of different phenotypic traits. Measurement of quantitative variation and qualitative traits will help to select distinguishable genotypes as parents to develop best tobacco varietal lines with higher leaf number, quality and stable lines with resistance to biotic and abiotic stresses. In this way diversity can be exploited to reach the future goals in tobacco crop and to increase the area, production and productivity in India.

References

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