AGRICULTURAL RESEARCH COMMUNICATION CENTRE

www.arccjournals.com / indianjournals.comIndian J. Agric. Res., 47 (3) : 192 - 199, 2013

EFFECT OF FOLIAR SPRAYS OF BIOREGULATORS ONGROWTH AND FLOWERING IN GLADIOLUS

T. Padmalatha* , G. Satyanarayana Reddy, R. Chandrasekhar,A. Siva Shankar1 and Anurag Chaturvedi2

College of Horticulture,Hyderabad- 500 030, India

Received: 29-09-2012 Accepted: 05-02-2013

ABSTRACTEffect of different plant growth regulator sprays (GA3, TIBA, CPPU and BR) on growth and flowering

of two gladiolus cultivars Darshan and Dhiraj was investigated for two consecutive years, 2008-09and 2009-10. Growth regulators were sprayed at 3 rd and 6th leaf stage. Cv. Darshan differed significantlywith cv. Dhiraj in respect to plant height, leaf area and flowered earlier. GA3 150 ppm followed bybrassinosteroid (BR) 10 ppm recorded maximum plant height, number of leaves and leaf area duringvegetative growth and resulted in earlier flowering. TIBA 100 ppm, TIBA 50 ppm and control recordedsignificantly minimum leaf area and showed delayed flowering. Cv. Dhiraj recorded maximumpercentage of plants flowered than the cv.Darshan. Cv. Darshan recorded significantly highest spikelength and inter floret length and minimum days to wilting of spike over the cv. Dhiraj. Cv. Dhirajwas significantly superior over cv. Darshan in respect of number of florets per spike and longevity ofspike. Maximum spike length and weight, number of florets per spike and spike field life wererecorded with GA3 150 ppm. Lowest values in respect of flower parameters were recorded with TIBAtreatments and control.

Key words: Brassinosteroids, CPPU, Flowering, Gladiolus, GA3, .

INTRODUCTIONGladiolus is one of the most important

commercial bulbous cut flower crops both in Indiaand abroad. It occupies an important position amongcut flowers due to its attractive spikes, sweetfragrance and high economic value. The spikes havevariety of colours with long lasting life and withstandlong distance transport and are highly used inherbaceous boarders, pots, vase and floraldecorations. In the recent past, the productivity ofthis flower has increased several folds which couldbe attributed to the introduction of high yieldingvarieties and adoption of improved package ofpractices. Of the various improved technologies,plant growth regulators play a vital role inmanipulating the plant growth and quality of flowerand increasing flower yield. Favourable effect oftraditional plant growth regulators like gibberellinsand tri iodo benzoic acid (TIBA) on growth and

flowering in gladiolus was reported by differentworkers in different parts of the country (Rajiv Kumaret al., 2002; Tawar et al., 2003; and Devi et al.,2007). But there was no organized research on theeffect of new class of plant growth regulators viz.,brassinosteroids (BR) and 2-chloro 4-pyridyl phenylurea (CPPU) on growth and flowering of gladiolusin India as well as in abroad. The presentinvestigation is aimed to ascertain the effect of foliarsprays of BR, CPPU along with GA3 and TIBA ongrowth and flowering in two gladiolus cultivars,Darshan and Dhiraj.

MATERIALS AND METHODSThe experiment was carried out at Herbal

Garden, Rajendranagar, Hyderabad for twoconsecutive years, 2008-09 and 2009-10. In thestudy, corms of gladiolus cultivars Darshan andDhiraj were used. There were 9 growth regulatortreatments viz., GA3 (100 and 150 ppm), TIBA (50

*Corresponding author e-mail : gandhamlatha@yahoo.com,1College of Agriculture, ANGRAU, Hyderabad-500 030, 2College of Home Science, ANGRAU, Hyderabad-500 030.

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and 100 ppm), CPPU (2.5 and 5.0 ppm), BR (5.0and 10.0 ppm) and control (water spray) eachreplicated thrice in factorial randomized blockdesign. Corms were planted at a spacing of 30 cm x20 cm and at a depth of 5 cm in September.Treatments were imposed as foliar sprays at 3 rd

and 6th leaf stage.

Well decomposed farmyard manure at 10 tha-1 was incorporated into all the experimental plotsuniformly as basal application. N, P, and K @200:200:300 kg/ha were applied in the form of urea,single super phosphate and muriate of potashrespectively. Urea was applied in 3 splits, the firstdose as basal application and other two split dosesat 30 and 60 days after planting. The entire dose ofsingle super phosphate and muriate of potash wereapplied at the time of planting as basal dose.Standard cultural practices were followed during theentire crop period for all the experimental plots.Observations on growth and flowering attributeswere recorded. Data were subjected to analysis ofvariance as applicable to factorial randomized blockdesign.

RESULTS AND DISCUSSIONData presented in the Tables 1, 2 and 3

indicates that the cv. Darshan was found to besuperior in respect of plant height and leaf area overthe cv. Dhiraj. With respect to number of leaves perplant, non significant differences were observedbetween the cultivars during both the years of study.It was noticed that in both the cultivars foliar spraysof plant growth regulators increased the vegetativegrowth at higher concentrations when compared tolower concentrations. Different growth regulatortreatments did not influence plant height, numberof leaves and leaf area at 35 DAP. However, at 65DAP, production of more number of leaves andsignificantly maximum plant height and leaf areawas with higher concentrations of GA3 and BR.Tawar et al. (2003) reported that vegetative growthincreased with increasing dose of GA3 in gladioluscv. Jester. Lowest plant height was recorded withTIBA after two foliar sprays. Among all the plantgrowth regulators, GA3 played a vital role inimprovement of vegetative growth characters ofgladiolus plants. In both the cultivars highestvegetative growth was observed with GA3 at 150ppm. This might be due to the fact that it enhances

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cell division by promoting DNA synthesis in cells.Singh et al. (2002) noticed an improvement in allgrowth parameters with increasing level of GA3. Theincrease in vegetative growth characteristics as aresult of GA3 application is also in close agreementwith the findings of Pranav Rana et al. (2005). Theproduction of more number of leaves and maximumplant height by GA3 150 ppm might be due to rapidgrowth and differentiation through endogenousauxins. Gibberellins cause stem elongation whichmay not be due to increased number of nodes andinternodes but results from rapid elongation ofinternodes due to both cell division and cellelongation. This might be the reason that GA3 150ppm treatment although increased the number ofleaves significantly over control at 65 DAP, it wason a par with BR 10 ppm, CPPU 5 ppm and GA3100 ppm. Similarly, the effect of GA3 in increasingplant height was also on a par with BR 10 ppmtreatment. Increase in plant height, number of leavesand leaf area with GA3 treatment has also beenreported by Pranav Rana et al. (2005) in gladiolus.

BR 10 ppm increased plant height, numberof leaves and leaf area significantly at 65 DAP andwas found on a par with GA3 150 ppm. Mandavaand Thompson (1983) reported that gibberellinscaused only elongation of the upper internodes but,BRs characteristically evoked both cell elongationand cell divison resulting in elongation, swelling,curvature and splitting of second internode in thebean second internode bioassay. Such activity ofBR is called brassisin activity. In all the bioassays, itwas found that BRs produce activity atconcentrations much lower than those effective forgibberellins. Our results are comparable with that ofBraun and Wild (1984) who found that BRstimulated leaf elongation in wheat and that ofGregory (1981) in brassisin treated barley seeds.Vardhini and Rao (2004) stated that the growthpromotion in tomato due to BR application wasassociated with elevated levels of nucleic acids,soluble proteins, reducing sugars, non-reducingsugars and starch. Huang et al. (2009) concludedthat BRs promote photosynthesis and growth bypositively regulating synthesis and activation of avariety of photosynthetic enzymes including Rubisco.

CPPU, a synthetic cytokinin at 5 ppm concentrationincreased plant height, number of leaves and leaf

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area significantly over TIBA and found to be thenext best treatment to GA3 150 ppm and BR 10 ppm.The increase in plant height may be ascribed to thestimulation of cell division and cell enlargement withthe application of CPPU as explained by Yu et al.(2001). Increased spear length in asparagus withfoliar spray of CPPU was reported by Ku et al.(2008).

The reduction in vegetative growth due toTIBA treatments might be due its anti- auxincharacter by preventing the transport of naturallyproduced auxins thereby reducing cell elongation.Darginaviciene and Maksimov (2001) reported thatTIBA inhibited both invivo and in vitro, the processesof specific IAA binding and physiological activity ofthe resulting IAA-protien complexes of spring wheatcoleoptile cell plasmalemma. These findings are inline with the reports of Devi et al. (2007) in gladiolus.

Cv. Darshan was significantly superior overthe cv. Dhiraj in respect of days to 50% flowering,days to flowering, per cent plants flowered, spikelength, number of florets per spike, inter floret lengthand spike longevity (Tables 4, 5, 6, 7 and 8) in boththe years. Varietal variation in respect of floweringperformance was reported by several workers.Growth regulat ing chemicals signi f icant lyinfluenced the days to 50% flowering, days toflowering, spike length, spike weight, number off lorets per spike and spike longevity. Thetreatments GA3 150 ppm and BR 10 ppm whichrecorded higher leaf area during the active growthstage flowered earlier in the two years of study.Treatment with TIBA at 50 and 100 ppm andcontrol which showed minimum leaf area at 65DAP delayed flowering significantly. This suggeststhat certain leaf area threshold constant isrequired as an inductive factor for flowering ingladiolus. This view gets support from theobservations of Ravidas et al. (1992) whoobserved delay in flowering with TIBA in the cv.Friendship. Timing the flower production is highlyprofitable in commercial flower crops than in anyother crop as they are highly perishable and theirdemand and supply fluctuates heavily unlike otherhort icultural commodi t ies. By adoptingappropriate cultural practices for meeting thefoliage needs, it is possible to induce early floralinitiation and flowering in gladiolus. T

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The interaction effect of cultivar and growthregulator treatments was significant on days to 50%flowering in both the years. Minimum number of daysto 50% flowering was recorded in the cv. Darshanin combination with GA3 150 ppm and was foundcomparable with BR 10 ppm and CPPU 5 ppm.Maximum number of days to 50% flowering wasobserved in the cv. Dhiraj with TIBA 100 ppm andTIBA 50 ppm. GA3 150 ppm followed by BR 10 ppmsignificantly increased mean spike length, numberof florets per spike, spike weight and spike longevityin both the years. These treatments were consistentand equally effective in increasing the leaf areaalmost during the entire crop growth period. Theincrease in leaf area thereby increased assimilatesynthesis might have contributed to increase in spikelength and weight by these treatments. GA3 treatmentresulted in maximum spike length and weight,number of florets per spike and spike field life. Theinteraction effect of cultivar and growth regulatortreatments was significant on spike length in boththe years. Maximum spike length was recorded inthe cv. Darshan with GA3 150 ppm, while minimumspike length was observed in the cv. Dhiraj with TIBA100 ppm and TIBA 50 ppm. The increased spikelength with GA3 might be due to rapid internodalelongation as a result of increased cell division andcell elongation in the intercalary meristem (Sauterand Kende, 1992). As GA3 promotes vegetativegrowth and increases the photosynthetic andmetabolic activities causing more transport andutilization of photosynthetic products might haveresulted in increased spike length. Similar results werealso reported by Pranav Rana et al (2005) and VijaiKumar and Umrao (2007). Number of florets perspike and field life were maximum with GA3 150ppm treatment followed by BR 10 ppm whereaslowest values were recorded in TIBA 100 ppm.Increase in number of florets per spike with GA3treatment has also been reported by Tawar et al.(2003), Pranav Rana et al (2005) and Vijai Kumarand Umrao (2007). The positive effect of GA3 inincreasing field life of gladiolus spikes was reportedby Gaur et al. (2003). Reduced number of floretswith TIBA might be due to reduced number of nodesassociated with inhibition of auxin induced cellelongation which resulted in reduced plant heightand spike length and there by minimum number offlorets and reduced field life. BR 10 ppm was found

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to be the next best treatment to GA3 150 ppm inimproving the floral attributes viz., spike length andweight, number of florets per spike and spike fieldlife. Similar improvement in flowering performance

of several cultivars of vegetables, including lettuce,radish, pepper and bush beans was reported byMeudt et al. (1984). Increased flowering with BRwas reported by Alvarez et al. (2005) in rose.

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