AST003 Marilyn Romaquin 11.40-12.001.ppt

7/29/2019 AST003 Marilyn Romaquin 11.40-12.001.ppt

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Effect of Gibberellic Acid(GA3) on Seedlessness of

Rambutan (Nephel ium

lappaceum, Linn.)

MARILYN E. ROMAQUIN, PhD

DANILO T. ELIGIO, PhD

Aklan State University

Banga, Aklan, Philippines


2/23

Rationale

Rambutan (Nephelium lappaceum, Linn.), under thefamily Sapindaceaeis native to Malaysia and Indonesia.

It is presently grown and cultivated in Thailand, Burma,

Vietnam, India, Sri Lanka, Australia and Puerto Rico. Rambutan is consumed fresh, canned, or preserved.

The colorful fruits are frequently used in displays withflower arrangements.

One major drawback for rambutan is its thin edible flesh

and big seeds which makes it relativelyexpensive for consumers.


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Rambutan flower buds could be induced to producefunctional stamen using a plant growth regulator.

The problem regarding the quality of rambutan cultivarscould be resolved with the proper timing in the

applications of plant growth regulators and fertilizers. Gibberellic acid (GA3) is one of the plant growth

regulators that has gained popularity and demandamong commercial fruit growers. The effect of GA3 inrambutan production was not yet tested.

In this study, the influence of GA3 at differentconcentrations applied at different timeson the quality of rambutanwas evaluated.

Rationale


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The study was conducted to evaluate the effect of GA3at different times of application and concentration on theyield and quality of rambutan fruits at harvest. Specificallyit is aimed to:

determine the effect of different concentrations ofGA3 applied at different times;

evaluate the effect of time of GA3 application on thequality of rambutan fruits; and

find out the interaction effect of GA3 and time ofapplication on the over-all yieldand quality of rambutan fruits.

Objectives


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This study was conducted at the Rambutan Project of theAklan State University, Banga, Aklan. The site ischaracterized by a sloping terrain with a ground elevation

between 10 to 20 meters above sea level. The locationfalls under type 3 climate which has no pronouncedseason, dry period in February through April and wetperiod during the rest of the year. The wettest mouth isNovember; the driest month is April (Source: PAGASARoxas City).

Experimental Site


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Nine 8-year old asexuallypropagated and bearing

rambutan trees withalmost uniform vigor,height and canopy wasused.

Experimental Trees


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The following culturalpractices were observedduring the duration ofthe research:

Weeding

Fertilization

Pruning

Cultural Practices


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A Split-plot in Randomized Complete Block Design(RCBD) with three replications was used in this study.

Main Treatment (A) - Time of application of GA3A1 - Before Bud Break (BBB)

A2 - Before Full Bloom (BFB)

A3 - Fruit Setting Stage (FSS)

Sub-treatment (B) - Varying concentration of GA3

B1 - 0 ppm (distilled water)B2 - 50 ppm

B3 - 100 ppm

B4 - 200 ppm

Experimental Design


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Total No. of Fruits perCluster

Length of the fruit

Fruit Diameter

Weight Per Fruit

Percent Seedless Fruit

Total Soluble Solids

pH of the Fruit at Harvest

Yield Per Branch Aril Weight

Data Gathered


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F-test Analysis of Variance (ANOVA)

Randomized Complete Block Design (RCBD) Duncans Multiple Range Test (DMRT)

Statistical Tools


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Results presented herein were reduced to theapplication of GA3 before bud break which showed positiveresponse to the induction of seedlessness. Application atother times did not significantly promote seedlessness.The results are presented in the succeeding graphs.

Results and Discussion


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Figure 1. Effect of GA3 on the Number of

Rambutan Fruits per Cluster.

0

1

2

3

4

5

6

7

8

9

10

0 50 100 150 200 250

Concentration (ppm)

NumberofFruitsperC

luster

b

a

aba


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0

5

10

15

20

25

30

35

40

45

0 50 100 150 200 250

Concentration (ppm)

Average

LengthofFruits(mm)

Figure 2. Effect of GA3 on the Length of

Rambutan Fruits (mm).

a

b b b


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Figure 3. Effect of GA3 on the Percentage

of Seedless Fruits.

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250

Concentration (ppm)

%

SeedlessFruits

c

b

ab a


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Figure 4. Effect of GA3 on TSS (Brix).

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250

Concentration (ppm)

TSS(DegreeBrix

)

b

a aa


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Production of seedless fruits occurs naturally inrambutan but rare with an average of 4.45 percent.

Upon application of 50 ppm GA3, seedlessnesssignificantly increased to 86.67 percent, attaining 100%

with 200 ppm. This was noted when GA3 was appliedbefore bud break. The consequence of seedlessness is the significant

reduction in the length of fruits but not in diameter andweight of individual fruits which remained comparable

to the seeded fruits.



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Decrease in the length of fruit was attributed to GA3 andnot on the number of fruits, which also significant byincreased with the application of GA3.

Correlation analysis between length and the number of

fruits was not significant (r=-0.155) while highlysignificant correlation was noted between seedlessnessand length (r=-0.673**).

Weight of aril, the edible portion, was not significantlyaffected by seedlessness, but seedless fruits was found to

be significantly sweeter over the seeded ones. This wasdisclosed by the positive highly significantcorrelation between seedlessness andtotal soluble solid (r= 0.83**).



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Yield was the same for all treatments. By and large, itcould be inferred that GA3 could induce seedlessness inrambutan.

However, it should be applied at the proper stage andconcentration. Based on the results of the study, 50 to200 ppm GA3 applied before floral bud break couldinduced seedlessness.



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Results showed that the number of fruits significantlyincreased with the application of 50 to 200 ppm beforebud break. Length and diameter of fruit, however, were

significantly reduced by GA3, as a consequence, theweight of fruit likewise decreased. Proportion of seedless fruit significantly increased with

the application of GA3 before bud break, whichdecreased at the later stages. Aril weight of the fruit

remained comparable among treatments.

Findings


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Fruits harvested from branches applied with GA3 beforebud break were found sweeter than fruits harvestedfrom branches applied before full bloom and at fruitsetting stage, as shown by the result of total solublesolids.

Significantly higher yield was produced from GA3treated branch before full bloom and at fruit settingstage due to higher number of harvested fruits.

Findings


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Application of GA3 can increase yield and induce higherproportion seedlessness in rambutan provided, GA3 isapplied at the proper concentration and time. GA3 at100-200 ppm sprayed before bud break produced highproportion of seedless fruits, which could solve problemof big seeds in rambutan without sacrificing aril weightand quality.

Findings


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Based on the results of the study, GA3should be used from 100 to 200 ppmbefore bud break if the intention is toinduce seedlessness.

Conclusion


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Maraming

salamat po!

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AST003 Marilyn Romaquin 11.40-12.001.ppt