Performance of Tuberose cv. Prajwal as Influenced by Different Plant Growth Enhancers

The present investigation on “Effect of plant growth enhancers on growth, f lowering and yield of tuberose cv. Prajwal” was carried out at Floriculture Research Farm, ACHF, NAU, Navsari , Gujarat during the year 2017 -2018. The experiment was laid out in a Randomized block design with three replication and thirteen treatments comprising four growth enhancers viz. , enriched sap of banana pseudostem (@ 5000, 10000 and 15000 ppm), brassinosteroid (@ 0.25, 0.50 and 0.75 ppm), GA 3 (@ 50, 100 and 150 ppm), BA (@ 50, 100 and 150 ppm) along with control (no spray).The treatments were applied as foliar spray at 60, 90 and 120 days after sprouting of bulbs. The experimental results revealed that foliar spray of enriched sap of banana pseudostem at 15,000 ppm (T 4) was found best with respect to all the growth & flowering parameters in terms of maximum plant height (74.8 cm), more number of leaves (70.20), greater leaf area (65.20 cm 2 ) , minimum days to both rachis emergence (37.53 days) and f loret opening (7 days), maximum length of spike (103 cm) and rachis (27.2 cm), more number of f lorets per plant (42.93), longevity of spike (12.73 days) and vase l i fe (11.20 days). Similarly, yield attributes viz. number of spikes per plant (2.67) and per hectare (2.77 lakh), bulbs per plant (2.60) and per hectare (2.70 lakh were also found higher in T 4 . In case of chemical attributes, maximum chlorophyll content (1.09 %) and essential oil (0.23 %) were also recorded in the same treatment.


INTRODUCTION
Tuberose (Polianthes tuberosa L.) also known as Rajnigandha is nati ve of Mexico and belongs to the famil y Asparagaceae.
It is one of the most i mportant bulbous plants of tr opical and subtropical region not only due to its white colour flowers, attractive spike and deli ghtful fragr ance, but easy cultivation and wide adaptability to var ying soils and agro -cli matic conditions. Among ornamental bulbous plants as val ued for their beauty and fragrance of the flowers, the tuberose occupies a ver y special and selective place and its flowers are ver y good source of essential oils which is used in the production of cosmetic and perfumer y products. Increase in flower produc tion, quality flowers and perfection in the for m of plants are the i mportant obj ectives in commercial flower production which can be obtained by using various growth enhancers wi thin in a short period of time and at a least cost, so the present investi gat i on on tuberose cv. Praj wal was carried out with obj ectives to find out the effect of different plant growt h enhancers on growth, flowering, yi eld and quality of tuberose cv. Praj wal.

MATERIALS AND METHODS
The present experiment was carried out during March, 2017to March, 2018 at Floriculture Research Far m, ASPEE College of Horticulture and Forestry, Navsari Agricultural Uni versity, Navsari, Guj arat, India. The climate of this r egion is t ypical tropical, characterized by fairl y hot summer , moderately cold winter and most humid and war m monsoon. The soil of Navsari campus is medium black, which is ver y deep, rich in organic matter and potash, having good water holding capacity and reasonably suitable for cult ivation of annual chr ysanthemum. The experi ment was laid out in a Randomi zed Block Design ( RBD) with three replication and thirteen treatments comprising four gr owth enhancers viz., enriched sap of banana pseudostem (at 5000, 10000 and 15000 ppm), brassino steroid (at 0.25, 0.50 and 0.75 ppm), GA 3 (at 50, 100 and 150 ppm), BA (at 50, 100 and 150 ppm) along with control (no spray).The treat ments were applied as foliar spray at 60, 90 and 120 days after sprouting of bulbs.
Healthy tuberose bul bs of cv. "Praj wal" free from pest and diseases and having homogenous size (2.5 -3.0 cm) were procured fr om Floriculture Research Far m, ASPEE College of Horticulture and Forestry, NAU, Navsari and were soaked for 30 mi nutes in Carbendezi m (0.1 %) solution and then dried in shade area. The planting was done by selecting weed free land which was properl y ploughed followed by harrowing and levelling on raised beds with a spacing of 30 cm x 30 cm at about 5 -7 cm below the ground and soil was pressed around the bulbs and all the standard package of practices were followed as per requirement of tuberose. The data collected for all the characters were subj ected to the statistical analysis by adopting "Anal ysis of Variance" technique as described by Panse and Sukhat me (1985) for Randomi zed Block Desi gn.

Effect on growth parameters
It is perceptible from the data as presented in Table -1 that, the various plant growth enhancers with their different concentration si gnificantly influenced the growt h attributes viz. plant height, number of leaves and leaf area. Significantly maxi mum plant height (74.80 cm), number of leaves per plant (70.20) and leaf area (65.20 cm 2 ) were recorded under the treatment T 4 (enriched sap of banana pseudostem @ 15000 ppm) which was statistically at par with T 10 , T 13 , T 6 and T 3 for all the three growth parameters and also with T 12 , T 5 and T 11 for plant height and leaf area, while the mini mum plant height (55.20 cm), number of leaves per plant (20.20) and leaf a rea (50.60 cm 2 ) were recorded with BR @ 0.75 ppm (T 7 ).
Enriched sap of banana pseudostem contain some biochemical such as gibberellic acid, NAA, cytokinin, chemi cals i.e. N, P, K, Ca, Mg, S, micronutrients (Mn, Cu, Zn, Zn) and beneficial micr obes (PSB, Rhizobium, Azotobact er and Fungus) . The most pronounced effect of gibberellins on the pl ant growth is an elongation of int ernodes. This increase in plant height mi ght be due to increased meristi matic activity due to enhance cell di vision and cell elongation. The si mil ar results were also obtained by Padmalatha et al. (2013), Sable et al . ( 2015) and Saj id et al. (2015) in gladiolus; Asil et al. (2011) and Singh and Shankar (2011) in tuberose. The mar ked i mprovement in growth attributes i.e. plant hei ght, number of leaves per plant and leaf area of the crop by enriched sap of banana pseudostem mi ght be due to increasing auxin level of tissue or enhance the conversion of tryptophan to IAA leading to the enhanced activit y of cell division and cell elongation throu gh the effect of gibberellic acid and cytokinin singl y or due to combine eff ect of both. This kind of results was also observed by Jadhav et al. (2015) in gladiolus cv. American Beaut y.

Effect on flowering parameters
Concerning the effect of various plant growth enhancers on flowering parameters in tuberose (Table -1), it was obser ved that enriched sap of banana pseudostem @ 15000 ppm (T 4 ) resulted in significantly mini mum days for emer gence of rachis (37.53 days) as well as that for floret opening (7.00 da ys) but was at par with T 10 , T 13 and T 6 for both the parameters and also with T 3 for days to rachis emer gence, while the maxi mum days for bot h were recorded in T 7 . This mi ght be due to reduction in j uvenile period due to gibberellins and convention of apic al meristem into flowering pri modia instead of production of leaves at the deter mination of j uvenile phase and the results are in accordance to those obtained by Wagh et al. (2012) in tuberose.
The significantl y maxi mum spike and rachis length of 103.00 an d 27.20 cm, respectivel y was also obtained with the application of enriched sap of banana pseudostem @ 15000 ppm (T 4 ), which was statistically at par with T 10 , T 13 , T 6 , T 3 , T 12 and T 5 , whereas mini mum value of spi ke lengt h (78 cm) and rachis length (19.10 cm) were recorded in treatment of BR @ 0.75. Increased spi ke length mi ght be due to rapid internode elongation as a result of increased cell division and cell elongation in intercalary meristem, Kumar et al. (2011) and Shanker et al. (2011) in tuberose.
Application of enriched sap of banana pseudostem sap @ 15000 ppm was also found to significantly increased the number of florets per spike (42.93) as well as longevit y and vase life of spi kes up to 12.73 and 11.20 days, respectively but was at par with T 10, T 1 3 , T 3 and T 1 2 , for all the three parameters and also with T 6 and T 11 in case of longevi ty and vase life of spikes. Whereas, mi ni mum values of 30.00, 8.87 days & 7.73 days, respectivel y were obt ained under T 7 (BR @ 0.75 ppm). This results might be due to fact that gibberellic acid mi ght be responsible for the continuous suppl y of food at the ti me of flowering from leaves, leading the longer floral longevi ty of spike in tuberose which is also supported by Singh and Shanker (2011). The beneficial effect of plant growth enhancers on vase life were mi ght be due to PGR especially cytokinins and gibberellins have positive effects on post -har vest life of cut flowers.

Effect on yield parameters
The data as presented in Table -2 revealed that the foliar application of enriched sap of banana pseudostem @ 15,000 ppm resulted in maxi mum number of spi kes per plant (2.67) and per hectare (2.77 lakh) in tuberose but was on the same bar when compared to T 10 . Increase in number of spi ke per clump may be due to increase in cell division and cell elongation with GA 3 and lower concentration of BA and NAA. Si milar r esult ware also reported by Kumar et al. (2011), Singh and Shanker (2011) and Shanker et al. (2011 in tuberose cv. Double, Jadhav et al. (2015) in gladiolus cv. Amer ican Beaut y.
Number of bulbs per plant and per hectare of tuberose was also influenced by different plant growth enhancers (Table -2). The maxi mum values for number of bulbs per plant (2.60) and per hect are (2.70 lakh) were recorded with enriched sap of banana pseudostem at 15,000 ppm (T 4 ) and was at par with T 10 , T 13 , T 12 and T 5 , whereas the mi ni mum values of 1.33 per plant and 1.24 lakh per hectare, respectivel y were obtained in BR at 0.75 ppm (T 7 ). Si milarly, maxi mum values of number of bulblets per plant (11.33) and per hectare (11.77 lakh) were also recorded T 4 which was at par with T 10 and T 13 , whereas the mi ni mum values were obtained in BR @ 0.75 ppm (T 7 ). Increase in bulb yield mi ght be due to bulbs used for planting has a reser ved food material in th e initial stage and that photosynthesi zed in leaves. Likewise it has two competing sinks i.e. flower spi ke or inflorescence and development of buds, supported by Kumar et al. (2011), Shanker et al. (2011 in tuberose cv. Double. BA promotes the sink activi ty of developing cor m and cor mels at expense of flower spi ke; this mi ght be the reason for increase in number of cor ms and cor mels, supported by Baskaran and Mishra (2007) in gladiolus cv. Chandini. Gibberellic acid is also known to enhance the role of photosynthesis by increasing chlorophyll content in leaves that further increases the availability of metabolites to the developing cor ms and cor mels, support ed by Jadhav et al. (2015) in gladiolus cv. American Beaut y. BA is known to promote cell division and anabolism, which mi ght have been resulted into increase in number of daughter cor ms as well as cor mels per plant, supported by Chopde et al. (2015) in gladiolus cv. American Beaut y.

Effect on chemical attributes
Chlorophyll content of the leaves plays a vital role in photosynthesis process for making the food. The data on effect of different plant growth enhancers on chlorophyll and essential oil content of tuberose cv. Praj wal as presented in Table -2  revealed that the significantly maxi mum chlorophyll content (1.09 %) was recorded under T 4 which was at par with T 10 (1.03 %), T 13 (0.98 %) while mini mum was observed in T 7 (0.35 %). Further, there was a nonsignificant effect of different treatments on essential oil content but higher essential oil (0.23 %) was recorded in treatment T4 and the least in T 7 . It mi ght be due to fact that the GA 3 retards chlorophyll degradation and helps in retaining hi gh leaf chlorophyll content, Faraji et al. (2011) in gladiolus cv. White Prosperity and BAP (cytokinin) also had an effective role in preventing chloroplast and chlorophyll degradation which resulted into decrease in leaf senescen ce and increase in total chlorophyll content, Saj id et al. (2015) in gladiolus. Table 1: Ef f ect o f p la nt g ro w t h e nha nc er s o n g ro w th a n d f lo w er ing i n tu bero se cv .
Pra jw a l