AG 09 Van Heerden

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van Heerden, P.D.R. Proc. Int. Soc. Sugar Cane Technol., Vol. 28, 2013______________________________________________________________________________________

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EVALUATION OF TRINEXAPAC-ETHYL (MODDUS) AS A NEW CHEMICALRIPENER FOR THE SOUTH AFRICAN SUGARCANE INDUSTRY

By

P.D.R. VAN HEERDENSouth African Sugarcane Research Institute,

Private Bag X02, Mount Edgecombe, 4300, South [email protected]

KEYWORDS: Cane Quality, Chemical Ripening,Moddus, Sugarcane, Sugar Yield.

Abstract

ALTHOUGH INFORMATION FROM Brazil and Australia indicate that trinexapac-ethyl

(Moddus) is an excellent new sugarcane ripener, there is no information on theresponse of South African varieties to this chemical. The objective of this investigationwas to establish the ripening potential of this chemical in a local variety and to compareresponses with current industry standards, 2-chloroethyl phosphonic acid (Ethephon)and fluazifop-p-butyl(Fusilade Forte). Evaluation was conducted in an irrigated plantand first ratoon crop of variety N32 at Pongola, South Africa. The field trial was laid outas a complete randomised design with 5 replicates per treatment. The nine treatmentscomprised: a) untreated control, b) Ethephon (1.5 litre/hectare) applied 84 days beforeharvest (DBH), c) Fusilade Forte (0.2 litre/hectare) applied 43 DBH, d) Moddus atthree rates (0.8, 1 and 2 litre/hectare) applied 70 DBH, e) Ethephon (1.5 litre/hectare)and Fusilade Forte (0.2 litre/hectare) applied in combination 84 and 43 DBH, and f)Moddus (0.8 and 1 litre/hectare) and Fusilade Forte (0.2 litre/hectare) appliedin combination 70 and 43 DBH. The various ripener treatments improvedestimated recoverable crystal (ERC) yields in the 12-month old crops by

between 1.64.9 tonnes/hectare when compared with the control. Moddusapplied at 0.8 and 1 litre/hectare achieved similar improvements as Fusilade Forte andEthephon, but at 2 litre/hectare outperformed the latter two ripeners by up to1.9 tonnes ERC/hectare. Best ERC yield responses were achieved in the threecombination treatments. However, the ModdusFusilade Forte combinationtreatments outperformed the standard EthephonFusilade Forte combinationtreatment by up to 1 tonne ERC/hectare. These results indicate that Moddus is an

effective sugarcane ripener under South African high-potential irrigated conditions andthat improvement in ERC yields exceeding those obtained with current industrystandards might be possible.

Introduction

Chemical ripeners are applied to the sugarcane leaf canopy by means of aircraft or ground-operated spray booms. The active compounds are subsequently absorbed through the leaves andcause chemical suppression of shoot and/or leaf growth (Alexander, 1973). Although chemicalripeners may reduce photosynthetic rates (Rostron, 1974), their suppression of growth has adominant effect on increasing sucrose accumulation by lowering the growth sink demand forsucrose. This accelerates sucrose storage within the stalk, leading to an increase in juice purity andstalk sucrose content (% cane) (Clowes, 1978; Solomon et al., 2001; Donaldson, 2002; Morgan etal., 2007). The main advantage of chemical ripeners is that they can suppress stalk and leaf growthmuch more rapidly and consistently than natural processes such as reduced temperatures or limitingsoil moisture (Alexander, 1973).


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combination treatments. For the individual treatments, Ethephon was applied 84 days beforeharvest (DBH) at 1.5 L/ha, while Fusilade Forte was applied 43 DBH at 0.2 L/ha according torecommended practice. Moddus was applied 70 DBH at 0.8, 1.0 and 2 L/ha.

The spray-to-harvest interval and application rates were based on previous researchconducted at SASRI (RA Donaldson, unpublished results).

For the combination treatments Ethephon was applied 84 DBH at 1.5 L/ha followed byFusilade Forte 43 DBH at 0.2 L/ha, while Moddus was applied 70 DBH at 0.8 and 1 L/hafollowed by Fusilade Forte 43 DBH at 0.2 L/ha.

Ripeners were applied to cane rows 25 in each plot while cane rows 1 and 6 acted asunsprayed guard rows. All spray mixtures were applied by CO2-pressurised spraying equipmentwith an overhead boom fitted with two TK-1 flood jet nozzles spaced 1.4 m apart. The spraymixtures were delivered in a water volume of 57 L/ha.

Measurements

A 12-stalk sample was taken from rows 2 and 5 of each plot at five different time intervalsbetween ripener application and harvest to determine a range of milling quality characteristics,including estimated recoverable crystal per cent (ERC%), which is an estimate of the recoverablevalue of sugarcane delivered to the sugar factory. The ERC% was calculated per stalk fresh weight(FW) as (equation 1):

ERC% = aS bNcF (Eq. 1)

where S = sucrose % per stalk FW; N= non-sucrose % per stalk FW; F = fibre % per stalk FW anda, b, c are industry determined factors representing the loss of each component (0.978, 0.535, and0.018 respectively) during sucrose extraction at the factory.

Stalk heights, stalk population counts, green leaf counts and lodge ratings were alsomeasured at the same time intervals from rows 3 and 4 of each plot. At harvest, these two centrerows were cut and bundled by hand and weighed using a hydraulic grab apparatus equipped with aload cell to determine cane yield (t/ha). The ERC yield (t/ha) per plot was subsequently calculatedas:

ERC yield (t/ha) = ERC% Cane yield (Eq. 2)

Statistical analysis

All the variables were analysed using one-way ANOVA. Each variable was first tested fornormality and homogeneity using the Shapiro-Wilk and Bartlett tests respectively (Genstat v.14).The post hoc test used was the least significant difference (LSD) (5%) test.

Results and discussionEffect of chemical ripener treatments on cane quality (ERC %)

The effects of the various ripener treatments on cane quality (ERC %) in the plant and firstratoon crops are illustrated in Figure 1. In the plant crop (black bars), ERC % was increased by

between 13.3 percentage units relative to the unsprayed control.

In terms of the individual ripener applications, Moddus applied at 1 L/ha (Mod 1) and2 L/ha (Mod 2) increased ERC % by at least 1 percentage unit more than the current industrystandards Ethephon (Eth) and Fusilade Forte (FF). The three combination treatments (Eth + FF,Mod 0.8 + FF and Mod 1 + FF) resulted in the largest increases in ERC % of respectively 3.3, 2.7and 3.2 percentage units relative to the control. Compared to the control, ERC % in the first ratooncrop (grey bars) was increased to a much larger extent than in the plant crop (black bars) by thevarious chemical ripener treatments (Figure 1). The ERC % was increased by between2.2-5.1 percentage units relative to the unsprayed control.


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Treatment

Con

trol

Eth FF

Eth+

FF

Mod

0.8

Mod

1

Mod

2

Mod

0.8

+FF

Mod

1+FF

Canequality

(ERC%)

0

2

4

6

8

10

12

14Plant crop

First ratoon

Fig. 1The effects of Ethephon

(Eth), Fusilade Forte

(FF) and

Moddus

(Mod) applied as individual and combination treatments oncane quality (ERC%). Values represent the mean of five replicates

and LSD (P


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Previous research has demonstrated statistically significant reductions in cane yield invariety N32 when Moddus was applied 92 DBH (RA Donaldson, unpublished results), whichsuggest that the shorter spray-to-harvest interval (70 DBH) employed in this study might be moreappropriate to minimise cane yield loss, but without compromising the desired increase in ERC %(Figure 1).

This suggestion is also in good agreement with previous findings from Brazil (Resende etal., 2000).

Treatment

Con

trol

Eth FF

Eth+

FF

Mod

0.8

Mod

1

Mod

2

Mod0.8

+FF

Mod

1+FF

Caneyield

(t/ha

)

0

20

40

60

80

100

120

140Plant crop

First ratoon



(FF) and Moddus

(Mod)

applied as individual and combination treatments on cane yield (t/ha). Valuesrepresent the mean of five replicates and LSD (P


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industry standards Eth and FF respectively.

Treatment

Control

Eth FF

Eth+

FF

Mod

0.8

Mod

1

Mod

2

Mod

0.8

+FF

Mod

1+FF

ERCy

ield

(t/ha)

0

2

4

6

8

10

12

14

16Plant crop

First ratoon



(FF) and Moddus

(Mod)

applied as individual and combination treatments on ERC yield (t/ha). Values

represent the mean of five replicates and LSD (P


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differences (Resende et al., 2000; Rixon et al., 2007). This is a hypothesis worthy of furtherinvestigation, because this chemical exclusively inhibits GA1 synthesis only (Rixon et al., 2007).

One of the major advantages that Moddus could bring to the South African sugarcane

industry is the ability of this chemical to effectively ripen sugarcane with juice purities in the rangeof 85% (Kingston and Rixon, 2007). In contrast, Ethephon only achieves good efficacy when juicepurities are below 75% (Eastwood and Davis, 1997). This opens up opportunities for usingModdus, not only in irrigated sugarcane, but also in certain rainfed environments and as a late-season ripener when sugarcane is inherently more mature than during the early part of the SouthAfrican milling season.

Another advantage is that contrary to Fusilade Forte, which kills the stalk apical meristem,Moddus-treated sugarcane will ultimately resume normal growth, which minimises the risk ofadverse effects developing when harvesting is disrupted or during unintended carry-over to thefollowing season.

Finally, exciting findings have been reported showing that this chemical induces largestimulation of root biomass and distribution in the following ratoon (Resende et al., 2000) as well asimproved ratooning (Di Bella et al., 2007). All the positive attributes discussed above bode well forthe wide-spread use of Moddus in the South African sugarcane industry upon product registration.Acknowledgements

Special thanks to Syngenta South Africa (Pty) Limited for funding this research and forpermission to publish the results. Special thanks to the management and technical team staff at theSouth African Sugarcane Research Institutes experiment farm in Pongola for provision of land andhuman resources during the experiments.

REFERENCESAlexander, A.G. (1973). Sugarcane Physiology. A Comprehensive Study of the Saccharum

Source-to-Sink System. Elsevier Scientific Publishing Co., Amsterdam.Clowes, M. St. J. (1978). Early and late season chemical ripening of sugarcane. Proc. S. Afr. Sugar

Cane Technol. Assoc., 52: 160165.Di Bella, L.P., Rixon, C., Armytage, P., Davies, B., Wood, A.W. and Sheedy, P. (2007). The

2006 Herbert Moddus pilot program. Proc. Aust. Soc. Sugar Cane Technol., 29: 368376.Donaldson, R.A. (2001). Effects of Fusilade Super and Ethephon as single and tandem treatments

on four sugarcane varieties. Proc. Int. Soc. Sugar Cane Technol., 24: 196198.Donaldson, R.A. (2002). Changes in the components of sugarcane culms from ripening with

Fusilade Super. Proc. S. Afr. Sugar Cane Technol. Assoc., 76: 106109.Eastwood, D. and Davis, H.D. (1997). Chemical ripening in Guyanaprogress and prospects.

Sugar Cane, 3: 417.Morgan, T., Jackson, P., McDonald, L. and Holtum, J. (2007). Chemical ripeners increase early

season sugar content in a range of sugarcane varieties. Aust. J. Agric. Res., 58: 233241.Kingston, G. and Rixon, C.M. (2007). Ripening responses of twelve sugarcane cultivars toModdus (Trin-Exapac Ethyl). Proc. Aust. Soc. Sugar Cane Technol., 29: 328338.

Resende, P.A.P., Soares, J.E. and Hudetz, M. (2000). Moddus, a plant growth regulator andmanagement tool for sugarcane in Brazil. Sugar Cane Int., April 2000: 59.

Rixon, C.M., Di Bella, L.P., Kingston, G., Dorahy, K., Davies, B. and Wood, A.W. (2007).Moddus a sugar enhancer. Proc. Aust. Soc. Sugar Cane Technol., 29: 318327.

Rostron, H. (1974). Chemical ripening of sugarcane with Ethrel and Polaris. Proc. Int. Soc. SugarCane Technol., 15: 953965.

Solomon, S., Shahi, H.N., Dutta Majumder, S.K., Singh, I. and Madan, V.K. (2001). Effect ofEthephon on sugarcane growth under sub-tropical climates. Proc. Int. Soc. Sugar CaneTechnol., 24: 174176.

Sweet, C.P.M., White, P.W. and Dodsworth, G.H. (1987). Commercial experience with chemicalsugarcane ripeners at Simunye sugar estate in Swaziland. Proc. S. Afr. Sugar Cane Technol.Assoc., 61: 121127.


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TEST DU TRINEXAPAC-ETHYL (MODDUS) COMME NOUVEAUMATURATEUR POUR LINDUSTRIE SUCRIERE EN AFIQUE DU SUD

Par

P.D.R. VAN HEERDEN

South African Sugarcane Research Institute, Private Bag X02,Mount Edgecombe, 4300, South Africa

[email protected]

MOTS CLS: Qualit de la Canne, Maturateur, Moddus,Canne Sucre, Rendement en Sucre.

RsumBIEN QUAU BRSIL et en Australie, leffet maturateur du trinexapac-ethyl (Moddus) sur canne sucre soit considr trs positif, il ny a pas dinformation sur la raction des varits dAfrique duSud cette substance active. Lobjectif des travaux prsents a t dvaluer cet effet maturateur surles varits locales et de comparer les rponses celles des maturateurs dj utiliss localement,2-chlorothyl phosphonic acid (Ethephon) et fluazifop-p-butyl (Fusilade Forte). Lessai a tconduit, Pongola en Afrique du Sud, sur une plantation et premire repousse irrigues de la varit

N32, selon un dispositif en blocs randomiss complets cinq rptitions par traitement. Les neuftraitements comprenaient : a) le tmoin non trait, b) Ethphon (1,5 litre/hectare) appliqu 84 joursavant rcolte (Day Before Harvest - DBH), c) Fusilade Forte (0,2 litre/hectare) appliqu 43 DBH, d) Moddus trois doses (0,8, 1 et 2 litre/hectare) 70 DBH, e) Ethphon

(1,5 litre/hectare) et Fusilade Forte

(0,2 litre/hectare) appliqus ensemble 84 et 43 DBH, et f)Moddus (0,8 et 1 litre/hectare) et Fusilade Forte (0,2 litre/hectare) appliqus ensemble 70 et43 DBH. Pour des cannes ges de 12 mois, par rapport au tmoin non trait, les diffrentsmaturateurs ont augment le rendement en sucre rcuprable estim de 1,6 4,9 tonnes/hectare. LeModdus, appliqu 0,8 ou 1 litre/hectare a la mme efficacit que le Fusilade Forte etlEthphon, mais 2 litres/hectare il dpasse ces deux maturateurs de 1,9 tonne en ERC/hectare.Les meilleurs rendements en ERC/hectare ont t obtenus avec les trois combinaisons. Cependant,la combinaison Moddus Fusilade Forte dpasse la modalit de rfrence, Ethphon - FusiladeForte, dune tonne de ERC/hectare. En Afrique du Sud, ces rsultats confirment leffet maturateurdu Moddus sur la canne sucre dans des conditions fort potentiel de production sous irrigation.Cette augmentation dERC dpasse celle attendue des maturateurs de rfrence.


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EVALUACIN DE TRINEXAPAC-ETIL (MODDUS) COMO MADURADORQUMICO PARA LA INDUSTRIA CAERA SUDAFRICANA

Por

P.D.R. VAN HEERDENSouth African Sugarcane Research Institute, Private Bag X02,

Mount Edgecombe, 4300, South [email protected]

PALABRAS CLAVES: Calidad de Caa, Maduracin Qumica,Moddus, Caa de Azcar, Rendimiento Sacarino.

Resumen

APESAR QUE LA

informacin que proviene de Brasil y Australia indican que el trinexapac-etil(Moddus) es un excelente madurador en caa de azcar, no hay informacin sobre la respuesta deeste madurador en las variedades sudafricanas. El objetivo de esta investigacin fue establecer lamaduracin potencial de este agroqumico en las variedades locales y comparar la respuesta con losactualmente utilizados en la industria, acido 2-cloroetilfosfonico (Ethephon) y Fluazifop-p-butil(Fusilade Forte). Las evaluaciones fueron conducidas en caa planta y soca 1 de las variedades

N32 y Pongola, South frica. El campo experimental fue establecido en bloque completos,aleatorizados con 5 replicas por tratamientos. Los 9 tratamientos comprendieron: a) control notratado, b) Ethephon (1,5 l/ha) aplicado 84 dias antes de la cosecha (DAC), c) Fusilade Forte(0,2 l/ha) 43 DAC, d) Moddus en tres dosis (0,8; 1 y 2 l/ha) aplicado 70 DAC, e) Ethephon(1,5 l/ha) y Fusilade Forte (0,2 l/ha) aplicado en forma combinada 84 y 43 DAC y f) Moddus

(0,8 y 1 l/ha) y Fluazifop (0,2 l/ha) aplicado en forma combinada 70 y 43 DAC. Los diversostratamientos aumentaron el azcar recuperable (ARE) en caa de 12 meses de edad fue entre 1,6 y4,9 t/ha comparados con el testigo. Moddus aplicado entre 0,8 y 1 l/ha mostro mejoras similares aFusilade Forte y Ethephon, pero 2 l/ha superolos dos ltimos maduradores hasta 1,9 t de ARE/ha. La mejor respuesta fue lograda en las tres combinaciones de los productos. Sin embargo, lacombinacin de Moddus-Fluazifop super a la combinacin estndar de Ethephon-FusiladeForte hasta en 1 t/ha de azcar recuperable. Los resultados indican que Moddus es un efectivomadurador de caa de azcar bajo las condiciones de riego de alto potencial productivo enSudfrica y estas mejoras de ARE podran dar la posibilidad de superar los resultados obtenidos conlos estndares actuales de la industria.


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AVALIAO DO ETIL-TRINEXAPAC (MODDUS) COMO UM NOVO MATURADORQUMICO PARA A INDSTRIA DE CANA-DE-ACAR SUL-AFRICANA

Por

P.D.R. VAN HEERDEN

South African Sugarcane Research Institute, Private Bag X02,Mount Edgecombe, 4300, frica do Sul

[email protected]

PALAVRAS-CHAVE: Qualidade de Cana, Maturador Qumico,Moddus, Cana-de-Acar, Rendimento de Acar.

ResumoEMBORA EXISTAM INFORMAEs provenientes do Brasil e da Austrlia indicando que o etil-trinexapac (Moddus) um excelente novo maturador de cana, no existem informaes sobre aresposta de variedades sul-africanas a esse novo qumico. O objetivo desta investigao foiestabelecer o potencial maturador desse qumico em uma variedade local e comparar as respostasaos padres atuais da indstria, o cido 2-chloroetil fosfnico (Ethephon) e o fluazifop-p-butil(Fusilade Forte). A avaliao foi conduzida em uma cana planta e primeira soqueira irrigadas davariedade N32 em Pongola, frica do Sul. O experimento de campo foi um delineamento em

blocos randomizados com 5 repeties por tratamento. Os nove tratamentos incluram: a) controleno tratado, b) Ethephon (1,5 litro/hectare) aplicado 84 dias antes da colheita, c) Fusilade Forte(0,2 litro/hectare) aplicado 43 dias antes da colheita, d) Moddus em trs dosagens (0,8, 1 e

2 litros/hectare) aplicados 70 dias antes da colheita, e) Ethephon

(1,5 litro/hectare) e FusiladeForte (0,2 litro/hectare) aplicados em combinao 84 e 43 dias antes da colheita, e f) Moddus(0,8 e 1 litro/hectare) e Fusilade Forte (0,2 litro/hectare) aplicados em combinao 70 e 43 diasantes da colheita. Os vrios tratamentos com maturadores aumentaram os rendimentos de cristaisrecuperveis em culturas de 12 meses em cerca de 1,6 a 4,9 toneladas/hectare em comparao aocontrole. Moddus aplicado a 0,8 e 1 litro/hectare alcanou aumentos semelhantes aos do FusiladeForte e do Ethephon, mas a 2 litros/hectare, superou os dois ltimos maturadores em at1,9 toneladas de ERC/hectare. As melhores respostas de ERC foram alcanadas nos tratamentoscom trs combinaes. Entretanto, os tratamentos combinados Moddus Fusilade Fortesuperaram o tratamento padro Ethephon - Fusilade Forte em at 1 tonelada de ERC/hectare.Esses resultados indicam que o Moddus um maturador eficaz sob as condies irrigadas de alto

potencial da frica do Sul e que o aumento nos rendimentos de ERC superaram aqueles obtidoscom os padres utilizados pela indstria.

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AG 09 Van Heerden