​Economics Analysis of Tomato Hybrid Seeds Produced through Soilless Systems

Tomato (Solanum lycopersicum L.) being an important vegetable crop with the largest coverage area among the vegetables in the world after potato. It belongs to the family Solanaceae. The total global area under tomato is 5.03 Million ha with production to the tune of 180.76 Million (FAOSTAT, 2019). India contributes 7.3% share of world production and it occupies 789 thousand ha. But the productivity in India (24.6 t ha^-1) is much lower compared to other countries viz., USA (96.8 t ha^-1), Brazil (71.9 t ha^-1) and China (59.3 t ha^-1). Quality seeds one of the important components contributing to productivity to the tune of 15-20 per cent. In developing countries like India, it is being a tedious task to supply quality seed at the proper time in the conventional production system as it is prone to abiotic/biotic stress, foreign pollen contamination, weeding, rouging and achieving isolation distance.  
       
Soilless culture is the technique of growing plants with roots immersed in the nutrient solution. These systems can be classified according to the techniques employed as hydroponics, aeroponics and aquaponics. The word hydroponics first appeared in a scientific magazine article (Science, Feb 178:1 by Gericke). Hydroponics is a technology for growing plants in nutrient solutions with or without the use of an artificial medium. Aeroponics is the cultivation of plants in an air or mist environment without the use of soil or aggregate media. It consists of enclosing the roots in a dark chamber and supplying a nutrient solution using a mister. Aquaponics is an integrated fish and plant production technology, essentially comprising of two sub-systems, such as, Aquaculture and Hydroponics.
       
Currently, about 3.5% of the worldwide area for vegetable production adopts soilless agriculture (Hickman). The advantage of these systems is plant nutrition and biotic stress can be controlled much more efficiently. Increasingly greenhouse farming and urban agriculture are being looked at as a more efficient and cost-effective way to produce vegetables (Kinoshita et al., 2016). Since the earlier experimental results revealed that the soilless system has wide potential for vegetable production. These efficient systems can be exploited for hybrid seed production as they share a common principle of production. The quality, cost and return analysis play a significant role in farm economics as it supports decision making at various levels for the farmers, researchers, policy makers, bankers and administrators.
       
Thus, the research questions were, to analyse the seed quality produced through the soilless system if it meets the quality standards is the system economical for hybrid seed production.
 

The present investigation was carried out through hydroponics and aeroponics for hybrid seed production of tomato (Solanum lycopersicum L), during 2017-19 at National Seed Project, University of Agricultural Sciences, GKVK, Bangalore. The experiment consisted of 12 treatments.

 

Treatment details of the experiment
 
Parental lines and seed treatment
 
Two female lines viz., TAG 1F and TAG 2F with their respective pollen parents (TAG 1M and TAG 2M) were collected from the BASF Nunhems Pvt Ltd and stored at -20°C for further usage. Seeds were subjected to seed treatment and dived into untreated control and treated (thiram @ 2g kg^-1 and chlorpyrifos @ 3g kg^-1 and dried in shade).
 
Methods of hybrid seed production
 
Conventional method
 
The field experimental plot contains 12 blocks with the net plot size of 5.4 × 3.6 m and the gross plot size is 6.4 × 4.5 m.  Tomato plants were at a row spacing of 0.9 m and 0.6 m between plants within a row. At the time of transplanting, urea, single super phosphate and muriate of potash were applied as the basal dose of nitrogenous, phosphorus and potassium fertilizer as per the recommended package of practices of the University of Agricultural Sciences, Bangalore (100:100:100 NPK/ha) for open field cultivation. Nitrogen was supplied as urea in three splits such as 50 per cent basal (during transplanting), 25 per cent each at 30 and 60 DAT (Days After Transplanting) respectively. The entire quantity of P and K were applied basally during transplanting.
 
Hydroponics method
 
In the drip system, pots were fitted with sponges. Twenty-eight days old seedlings were transplanted into each pot, connected with drip along with the timer for delivering Hoagland’s nutrient solution for 3 hours per day (Morning-45 min, afternoon-90 min and night-45 min).
 
Aeroponics method             
 
The experiment in aeroponics contains six chambers with the individual timer and motor. Twenty-eight days old seedlings were placed on the foam sheet. Six plants were accommodated per chamber, Hoagland nutrient solution was sprayed to root zone at an interval of 30:360 sec and 30:180 sec on and off-cycle in morning and night respectively (Fig 1).


 
Seed quality parameters
 
Test weight (g), seed size were analysed under BIOVIS PSM Seed Image Analyser for average seed length and seed width of 100 seeds for each replication, seed germination (%) (Anonymous, 2017) seedling vigour index I (Abdul Baki and Anderson, 1973). 
 
Cost and benefit analysis
 
Cost of cultivation was calculated based on 1) Variable cost which varies with the level of production like labour cost, land preparation, pollination labour cost,  seedling/seeds, fertilizers, nutrient solution, plant protection chemicals, staking materials, pruning and miscellaneous. 2) Fixed cost is the cost that does not vary with the level of production viz., land revenue, managerial cost, risk premium, amortized establishment cost. Amortization is an accounting technique that reduces cumulative establishment cost at a discount rate over the economic life of the plantation.  Net house (15 years), staking iron roads (20 years), sponge for hydroponics (3 years) and others (10 years) with the 4 % discount and annual maintenance cost. Where:
A - Amortized establishment cost.
P - Establishment cost.
i - Discount rate. 
t - Economic life.
       
The number of labours was calculated based on the number of plants and operation involved in the particular method of hybrid seed production. The average salary was 280 Rs Day^-1 except for pollination where skilled labours were employed with an average salary of 300 Rs Day^-1. The cost of fertilizers used for the soilless system was calculated based on the average amount of nutrients consumed.
       
The benefit was analyzed and gross returns, net returns, returns per rupee of variable cost, returns per rupee of cost of cultivation, incremental cost, incremental benefit and incremental benefit-cost were computed.
 
Statistical analyses
 
The experimental data were statistically analysed by adopting Completely Randomized Design with Factorial concept (FCRD) as per Gomez and Gomez adopting “Fisher Analysis of Variance Technique” with the Critical difference values were computed at 5% level wherever F test was significant.

The quality of hybrid seed produced in hydroponics and aeroponics was compared with the conventional system and the results revealed that the soilless system performed better than the soil system. Test weight was significantly influenced by parental lines and method of seed production. TAG 1 (0.39 g) parental line had the higher test weight compared to TAG 2 (0.35 g). Among the methods of seed production, aeroponics (0.39 g) recorded higher test weight which was on par with hydroponics (0.38 g) and lower in the conventional system (0.34 g). The average seed size analysed in the biovis image analyser showed a significant difference among the methods of hybrid seed production. The data obtained revealed among the method of hybrid seed production, higher seed length as recorded in aeroponics and hydroponics (0.52 cm) and lower was recorded in the conventional system (0.47 cm). Seed width varied significantly for parental lines, higher width was recorded in TAG 1 (0.36 cm) (Table 1). Seed germination of hybrids did not significantly vary among the parental lines, seed treatment and method of hybrid seed production. SVI-I varied significantly among seed treatment, treated seeds (S₂) recorded higher SVI-I (2749) compared to untreated S₁ (2672), among the methods of hybrid seed production hydroponics (2821) recorded higher SVI-I and lower was recorded in conventional (2577) (Table 2). 




       
The differences in test weight and seed width among the parental lines are genetically controlled. The difference in test weight and seed size among the methods of hybrid seed production may be due to controlled nutrient feeding as the nutrients are present in ionic forms with the precise nutrition, pH and temperature, compared to the complexities of mineralization, mobilization and uptake by the plant in the conventional system. This is likely due to soilless system provides more favourable sink/source balance which enhanced the better root-shoot growth (Gruda; 2009, Liu et al., 2016) (Fig 2 and Fig 3). The seeds were viable among all the treatments thus, the results were non-significant for seed germination and field emergence as it in turn indicates liveness and quality of seeds. It is inferred that soilless agriculture could be a promising tool for quality healthy tomato seed production under protected cultivation (Kaddi et al., 2014).




       
The cost and return structure of hybrid seed production of tomato in conventional, hydroponics and aeroponics were calculated and presented in Table 3. Based on the economic calculation, the variable cost involved the working capital cost and it was comparatively lower for the conventional method (Rs. 592503/-) followed by aeroponics (Rs. 626883/-) and it was found higher in hydroponics (Rs. 720944/-). Due to the cost incurred for nutrients was higher in the hydroponics method (Rs. 243424/-), followed by aeroponics (Rs. 90789/-) and lower in conventional (Rs. 22000/-) (Appendix-I). The fixed cost was higher for aeroponics (Rs. 920360/-) followed by hydroponics (Rs. 786276/-) and lower was for conventional system (Rs. 295304/-). This is due to higher establishment cost in the soilless based method of hybrid seed production.


       
The returns were calculated based on the yield obtained in the individual method of hybrid seed production and the procurement cost of hybrid seeds. Higher returns over total cost were noticed in aeroponics method (Rs. 1672637/-), followed by hydroponics (Rs. 1456380/-) and lower in the conventional method (Rs. 748586/-) (Table 4).


       
The return per rupee (B:C ratio) was higher in aeroponics (2.08), followed by hydroponics (1.97) and lower in conventional method (1.87). The incremental cost and benefit ratio was calculated to understand the benefit ratio over the other methods. IB:C ratio for aeroponics over conventional method recorded the higher ratio (2.38) than hydroponics over conventional method (2.12). Thus, based on the cost and return analysis it was found that higher cost was incurred for the soilless method of hybrid seed production compared to soil-based seed production as it involved the aeroponics and hydroponics chamber, net-house for protected cultivation since the nutrients were supplied at regular interval basis which took the major share for a fixed cost. Even with higher investment cost, returns were also higher in the soilless agriculture method of hybrid seed production due to high density under hydroponics (2.8 plant/m²), aeroponics (3.1 plant/m²) compared to a soil-based method of hybrid seed production (1.7 plant/m²). There was an increased seed yield of 1g plant^-1 in the soilless method, which in turn increased the B:C ratio (Julian et al., Treftz and Omaye,). Seed quality is a critical aspect of agriculture to ensure food security. It is affected by a number of complex genetic, environmental factors. Phenotype is not just based on the interaction of genotype and environment but also on the management, by providing better environment condition with proper nutrients. The complete potentiality of the plant could be harvested, which also ensures the seed quality. These models can be exploited for hybrid seed production especially where one pollination would yield many seeds and for high-value low volume crops.

We would like to acknowledge the Confederation of Indian Industry and Science and Engineering Research Board for awarding PM fellowship. The authors would like to thank BASF Nunhems Private Ltd for being the partner company and sharing the research materials. Finally, we extend our gratitude to the Directorate of Research UAS, GKVK, Bangalore, for funding the project.