Influence of presowing seed treatment with inorganic nutrients on seed and seedling quality characters of petunia CV. MIX

Introduction

Rapid and uniform field emergences are the two essential pre requisite to increase the yield, quality and ultimately the profits in annual crops (Parera and Cantliffe, 1994) [11] . Pre-sowing invigouration is one such technological highlight focused to the above goals. Pre-sowing seed invigouration treatments are numbered many by the researchers (Sundaralingam et al., 2001) [15] and all are claimed to have invigourative effect at field for enhancing the yield of crop to a tune of 10-15 per cent (Vijayakumar et al., 1988) [17] . Seed fortification with inorganic nutrients is one such seed treatment for invigourating the seed before sowing. Nutrients are the other alternatives to growth regulators as they are cost effective and the lethality rate will be lesser at supra optimal levels. In addition they are also easily available than the growth regulator. Adoption of any presowing technique for a particular crop required standardisation work as the response of the seed to the pre-sowing treatment varies with chemical, concentration and duration of the treatment. Hence the present study was formulated to standardize the seed fortification treatment with micro and macro nutrients for enhancing the production of elite seedling at primary and secondary nursery of petunia cv. Mix.

Materials And Methods

The fresh seeds of petunia cv. Mix obtained from M/s Namdhari seeds were soaked in equal volume of nutrient solutions viz., Magnesium sulphate (MgSO 4 ), Manganese sulphate (MnSO 4 ), Ferrous sulphate (FeSO 4 ), Zinc sulphate (ZnSO 4 ), Borax, Potassium chloride (KCl) and Potassium dihydrogen phosphate (KH 2 PO 4 ) in two different concentration viz., 0.5 and 1% for a duration of 8 and 16 h along with water. The seeds were shade dried for one day and were evaluated for the seed and seedling quality parameters viz., germination (%) (ISTA, 1999) [4] , Speed of emergence (Maguire,1962) [8] , root and shoot length (cm), drymatter production 20 seedlings (mg) and vigour index (Abdul Baki and Anderson, 1973) [1] after 10 days of sowing. The germination test was conducted in germination room maintained at 25 °C and 95 ± 2% RH adopting the top of paper method. Based on the results the responsive duration of fortification irrespective of micro and macro nutrients was selected and the seeds fortified for 16 h in the above mentioned chemicals were evaluated at nursery, which consist of both primary and secondary nursery owing to the smallest and lightest nature of the seed. The primary nursery was raised with earthern pots, while the secondary nursery was with pluck trays (8.5 cm dia). At nursery, after 15 days in primary and after 25 days in secondary, the seed and seedling quality characters viz., emergence at primary nursery (%), establishment at secondary nursery (%), root and shoot length at secondary nursery (cm), fresh weight seedling -1 (g) and dry weight seedling -1 (g) were analysed. The data gathered were analysed statistically adopting the procedure described by Gomez and Gomez (1984) [3] .

Results And Discussion

In the present study highly significant difference were obtained due to nutrients and soaking duration for the seed quality characters viz., germination (%) and speed of emergence, while significant difference was observed only due to nutrients for drymatter production (mg 20 seedlings - 1 ). However, root length (cm), shoot length (cm) and vigour index observed a non-significant influence due to both nutrients and soaking duration (Table 1). The results revealed that seed treatment with KH 2 PO 4 and KCl at 1.0 per cent invigourated the seed better than others by recording 20 and 24 per cent higher germination than water soaking and control respectively. The invigourative response expressed by the other nutrients were in the order of MgSO 4 (0.5 and 1 per cent), ZnSO 4 (0.5 per cent), KH 2 PO 4 (0.5 per cent), MnSO 4 (0.5 per cent), FeSO 4 (0.5 per cent), borax (1.0 per cent), KCl (0.5 per cent) and ZnSO 4 (1.0 per cent) while the least was observed with FeSO 4 (1.0 per cent) compared to both water soaking and control. Not only the germination but also the seed quality characters evaluated in terms of seedling vigour characters and computed vigour index values were higher in the seeds fortified with KH 2 PO 4 and KCl and the efficacy of other nutrients were in order, as that of germination. Between the durations, 16 h was found to be effective than 8 h. The better performance of KH 2 PO 4 and KCl might be due to influence of K that had impregnated into the seed through seed coat and had promoted quicker germination, early growth with better stamina (Srivastava and Singh, 1973) [13] and these early vigour might had been useful for the increased energy production and these stored food resources were utilised for growth (Wellingford, 1980) [18] . In addition, in KH 2 PO 4 the presence of P could have act as an energy carrier in biochemical reaction with K including the N uptake in plant metabolism (Beringer, 1978) [2] . Okanenko and Bershtein (1996) reported that K improved the oxidative phosphorylation, utilization of sugar along with pentose phosphate cycle, synthesis of mitochondria and the activity of ATPase and other enzymes and these could have improved the germination capacity of seeds. Similar increase in germination by pre-sowing seed treatment with KH 2 PO 4 was also reported by Mehrotra et al. (1968) [9] in wheat and Vijayakumar et al. (1988) [17] in bhendi. The increase in germination by KCl treatment might also be due to the action of K and Cl which acted as agents during the hydration of the seed and maintained a state of swelling which is congential for the development of plasma colloids which helps in seedling development. (Kamfer and Zehlar, 1967) [6] . The results of the present findings also could be due to the above reasons and was supported by Punithavathi (1997) [12] and Kalarani et al. (2001) [5] in ragi. On the other hand, the deleterious effect of higher concentrations might be due to their toxic effect on physiological and biochemical processes within the cell (Swartz, 1941) [16] . However seed fortification with FeSO 4 (1 per cent) was found to deleterious for seed germination. The evaluations of the fortified seeds at nursery also expressed that the nursery emergence and establishment of seeds at primary and secondary nurseries exposed similar sequential order of performance as that of germination (Table 2) highlighting the efficacy of KH 2 PO 4 for seed fortification that had extended upto the nursery period in production of elite seedling for better establishment at main field. Subrhamanyan and Misra (1980) [14] also reported that seed treatment with KH 2 PO 4 as a compound resulted in maintenance of higher water balance in the tissue and enhanced the photosynthetic activity, and ultimately contributed to increase in establishment. Thus the study revealed that  Seed fortification with KH 2 PO 4 and KCl (1 per cent) improved the emergence and seedling establishment at primary and secondary nursery.

Conclusion

The study highlights that pre-sowing seed fortification with KH 2 PO 4 and KCl significantly enhances seed germination, speed of emergence, and overall seedling vigor in petunia cv. Mix. Seeds treated with 1% KH 2 PO 4 and KCl exhibited superior performance compared to other nutrient treatments, showing increases of up to 24% in germination rates. The extended soaking duration of 16 hours proved more effective than 8 hours. The improved seed quality and seedling establishment at both primary and secondary nurseries underscore the efficacy of these treatments in boosting crop productivity and quality. Standardizing such techniques can offer substantial benefits for enhancing seedling performance and crop yield.

References

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