Concentrations of Stimulation on Performance

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Effects of Various Frequencies and

Concentrations of Stimulation on Performance

of Some Hevea Clones in Cambodia

S. Mak1_{, C. Chhek}1_{, S. Yin}1 _{and R. Lacote}2

1_{Cambodian Rubber Research Institute (CRRI)} 2_CIRAD

IRRDB-CATAS International Conference, Hainan, China October 18th – 22nd _{. 2010}

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INTRODUCTION

Yield stimulation offers opportunities for reducing frequency of tapping from high frequency tapping (HFT) to low frequency tapping (LFT).

Intensity of stimulation was modulated according to clonal characteristics (Serres et al., 1988, Jacob et al., 1989, Gohel et

al., 1995 and 1996, Lacote et al., 2010).

In Cambodia, the S/2 d3 tapping system with stimulation has been used in routine.

Cambodian Rubber Research Institute (CRRI) has been developing research on tapping system to evaluate the influence of stimulation on yield with given low frequency tapping S/2 d4.

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OBJECTIVE

To investigate the effects of various

frequencies and concentrations of stimulation

on performance of clones GT 1, RRIM 712

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Rainfall recorded over ten years from 2000 to

2009 in Experimental Station of CRRI

1488.6 1575.0 1335.4 1002.6 _986.5 1448.3 1720.2 1074.2 1677.7 1457.8 0 400 800 1200 1600 2000 (m m /y e a r) 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Years

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MATERIALS AND METHODS

1. Clones : GT 1, RRIM 712 and IRCA 230 2. Tapping panels : BO-1

3. Location : Experimental Station of CRRI. 4. Design of experiment : RCBD

5. Tapping systems : S/2 d4 7d/7

6. Number of treatments : 4 (T0, T1, T2 and T3) 7. Number of replications : 4

8. Plot size : 120 trees per plot for clone GT 1

: 108 trees per plot for clone RRIM 712 : 90 trees per plot for clone IRCA230

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MATERIALS AND METHODS

• Tapping systems and number of treatments are:

T0 : S/2 d4 7d/7 ET 2.5% Pa(1) 4/y (control)

T1 : S/2 d4 7d/7 ET 2.5% Pa(1) 8/y

T2 : S/2 d4 7d/7 ET 2.5% Pa(1) 12/y

T3 : S/2 d4 7d/7 ET 3.3% Pa(1) 4/y

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Average yield (g/t) of clone GT1 increased with intensity

of stimulation frequency

2259.9 b 2681.1 ab 2825.8 a 2317.1 b 0 1000 2000 3000 Y ie ld s ( g /t )

ET 2.5% 4/y ET 2.5% 8/y ET 2.5% 12/y ET 3.3% 4/y Treatments

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Average yield (g/t) of clone RRIM 712 increased with

intensity of stimulation frequency

3054.1 c 3588.6 b 3947.5 a 3427.3 b 0 1000 2000 3000 4000 Y ie ld s (g /t )

ET 2.5% 4/y ET 2.5% 8/y ET 2.5% 12/y ET 3.3% 4/y

T reatments

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Average yield (g/t) of clone IRCA 230 increased with

intensity of stimulation frequency

2545.1 3139.6 3356.6 2562.6 0 1000 2000 3000 4000 Y ie ld s (g /t )

ET 2.5% 4/y ET 2.5% 8/y ET 2.5% 12/y ET 3.3% 4/y

Treatments

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Yields (g/t) comparison of clone GT 1, RRIM 712 and IRCA

230 obtained from treatment T2 during the initial four years.

Yields of treatment T2 during the initial four years of clone GT 1, RRIM 712 and IRCA 230

1500 2000 2500 3000 3500 4000 4500 2006-07 2007-08 2008-09 2009-10 Y ie lds (g/ t) GT 1 RRIM 712 IRCA 230

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Average yield (g/t) comparison of clone GT 1, RRIM 712 and

IRCA 230 obtained from treatment T2 during the initial four

years of the experiment.

2825.8 3947.5 3356.6 0 2000 4000 Y ie ld s (g /t ) GT 1 RRIM 712 IRCA 230 Clones

Average yield of clone GT 1, RRIM 712 and IRCA 230 obtained from treatment T2 during the initial four years

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Effect of ethephon stimulation frequency on average yield, girth increment and %TPD of clone GT 1, RRIM 712 and IRCA 230

obtained from treatment T0: S/2 d4 7d/7 ET 2.5% Pa(1) 4/y during the initial four years from 2006 to 2010.

0 2 4 6 GT 1 RRIM 712 IRCA 230 Clones

Average yield (kg/t), Girth increment (cm) and %TPD of three clones obtained from treatment T0

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Effect of ethephon stimulation frequency on average yield, girth increment and %TPD in clone GT 1, RRIM 712 and IRCA 230 obtained from treatment T1: S/2 d4 7d/7 ET 2.5% Pa(1) 8/y during

the initial four years from 2006 to 2010.

Average yield (kg/t), Girth increment and %TPD of three clones obtained from treatment T1

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Effect of ethephon stimulation frequency on average yield, girth increment and %TPD of clone GT 1, RRIM 712 and IRCA 230 obtained from treatment T2: S/2 d4 7d/7 ET 2.5% Pa(1) 12/y during

the initial four years from 2006 to 2010.

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Effect of ethephon stimulation frequency and concentration on average yield, girth increment and %TPD in clone GT 1, RRIM

712 and IRCA 230 obtained from treatment T3: S/2 d4 7d/7 ET 3.3% Pa(1) 4/y during the initial four years from 2006 to 2010.

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Conclusion

 High yielding clones are possible under S/2 d4 7d/7 frequency if higher frequency of stimulation are imposed.

 For medium yielding clone like GT 1, high stimulation per year can be applied without adverse effects.

 Productivity of all clones can be increased considerably by 8 to 12 stimulations per year under S/2 d4 7d/7 system of tapping.

 Yield stimulation under S/2 d4 7d/7 can be practiced in all clones (medium and high yielding) by 8 to 12 stimulations per years.

 Incidence of tapping panel dryness (TPD) is lower for clone IRCA 230 as compared to clones GT 1 and RRIM 712.

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