Jpn. J. Trop. Agr. 50 (2) : 87-91, 2006

Growth and Production of Amorphophallus at Different Shading Levels in Indonesia

Edi SANTOSA,Nobuo SUGIYAMA*,Miki NAKATAand 0 New LEE

GraduateSchool of Agricultural and Life Sciences,The Universityof Tokyo

Abstract Amorphophallus paeoniifolius (Dennst.) Nicolson (elephant foot yam) and A. muelleri Mill. are commonly cultivated under tree canopies. They are usually harvested two to three years after the planting of one-year-old . However, information about suitable cultivation periods and shading levels is limited. The present study was conducted in a field located in Bogor, West Java, over a period of three years at four shading levels: control (0%), 25, 50 and 75%. Regardless of the shading level, the fresh mass of the corms increased exponentially in a year in elephant foot yams, while linearly in A. muelleri. Leaf size increased with the increase in the shading level, resulting in the production of large daughter corms at a low light intensity. About half of the A. muelleri flowered in the third year under the 75% shading condition, while no elephant foot yam plants flowered under the same condition. Daughter corms reached a commercial size two years after planting in A. muelleri and three years after planting in elephant foot yams under the 75% shading condition. These results suggested that both are shade-loving plants and that A . muelleri could be harvested one year earlier than elephant foot yams under shading conditions. Key Words: Agroforestry, Amorphophallus muelleri, Amorphophallus paeoniifolius, Low light intensity, West Java

the light intensity affects the time to flower. The Introduction objective of the present study was to determine at

In Java, Indonesia, edible Amorphophallus species which time corms could be harvested when elephant such as Amorphophalluspaeoniifolius (Dennst.) Nicolson foot yams and A. muelleri plants were grown at

(elephant foot yam) and A, muelleri Mill. are commonly different light intensities. cultivated under tree canopies in home gardens and timber plantations, or between other crops in upland Materials and Methods fields (Jansen et al., 1996; Santosa et al., 2002, 2003). The present study was conducted in a field located

They provide important sources of additional income at the Cikabayan Experimental Farm, Bogor Agricul- and carbohydrates for households in villages close to tural University, Indonesia (6•‹36•ŒS; 106•‹48•ŒE; 240 m timber plantations in Java (Santosa et al., 2003). above sea level). The soil type was a Latosol with a pH

Although Amorphophallus species are considered ranging from 5.8 to 6.5, and with a structure consisting to be suitable crops for agroforestry, the effects of of 12.8% sand, 29.1% silt and 58.1% clay. shading vary among the species. Pushpakumari and Corms of elephant foot yam and A. muelleri plants

Sasidhar (1992) reported that the yield in elephant foot were cultivated once a year from September to July yams decreased by 66% if the light intensity was (during the rainy season) in 2002/2003, 2003/2004 and reduced to 25% of full sunlight, while Inaba (1984) 2004/2005. In the first planting (2002), one-year-old stated that the dry mass of A. konjac corms increased corms (40.3•}5.7 g for elephant foot yams and 49.4•} by shading (50%of full sunlight). There are no reports 7.4 g for A. muelleri) were used. The one-year-old corms on the effect of the light intensity on the growth of A. were raised from cormels for elephant foot yams and muelleri. from bulbils for A. muelleri. Seed corms were harvested

Elephant foot yams and A. muelleri are usually in July 2002 and stored at room temperature until they harvested when corms reach a commercial size (950 were planted in September 2002. In the second and g), but before they flower. Flowering usually occurs third year plantings, seed corms harvested in the first three to four years after the planting of one-year-old and second year plantings, respectively, were used. corms. However, it remains to be determined whether From harvest to planting, corms were stored in a

Received Jan. 26, 2006 storage house at temperatures ranging between 27 and Accepted Mar. 11, 2006 * Corresponding author 29•Ž and at a relative humidity of 70-85%. Bunkyoku, Tokyo 113-8657, Japan The experiment was designed as a randomized [email protected] complete block with four replications. Shading nets, 88 Jpn. J. Trop. Agr. 50 (2) 2006

which reduced the light intensity by 25, 50 and 75%, and 75% shading treatments in either species. It is were spread over the plot before planting. No shading likely that the leaves of the A. muelleri plants were

net was used for the control treatment. In each more sensitive to direct sunlight than those of elephant

replication, 20 corms with their buds at the top were foot yam plants.

planted at a spacing of 50 cm•~50 cm in a 10-15 cm The life span of the leaves was longer under

raised bed at a depth of 10-12 cm. Based on preliminary shading conditions than under the control condition,

observations, some plants showed a severe reduction irrespective of the year (data not shown). Inaba and

in growth or died under full sunlight. Therefore, the Chonan (1984) also reported that leaves grown under

number of plants in the control treatment was increased full sunlight exhibited a shorter life spans than those

to ensure the necessary number of corms in the third grown under 50% shade (40 days in the control vs.

year. At planting, about 500 g of rice husk was applied three months under 50% shading).

below the corms to reduce corm rot. The corms were The number of leaves differed significantly in two

then covered with a mixture of soil and goat manure of three years between the treatments for the elephant

(3:1, v/v). foot yam and A. muelleri plants. Shading treatments

The monthly rainfall (average, minimum and significantly decreased the leaf number in both elephant

maximum values), average daily temperatures, and foot yam and A. muelleri plants, although there were

relative humidity in the first, second, and third years no significant differences between the 25, 50 and 75%

are shown in Table 1. Irrigation was carried out at a shading conditions (Table 2). In agreement with these

rate of 2-31 per if there was no rainfall for 7 days. results, Caesar (1980) reported that Xanthosoma and

Leaf numbers and petiole lengths were measured Colocasia plants showed a smaller number of leaves

every week, and plants were harvested in mid-July of under shading conditions than under full sunlight. The

each year after they had entered dormancy. The short life span of the leaves might lead to the production

diameter, height, and fresh mass of the daughter of new leaves, resulting in a larger number of leaves

corms were measured after the cormels had been under full sunlight.

detached. Numbers and fresh mass of the cormels were Shading treatments significantly affected the length

also recorded. The dry mass of the daughter corms of the petioles and rachis in both species in all the

was measured after oven-drying at 65•Ž for 3 days. In three years,except for the rachis length of the elephant

the third year harvest (2005), corms displaying any foot yam plants in 2004/2005 (Table 3). Control plants

disease and corms formed after flowering were displayed the shortest petioles, while the longest examined. petioles were produced under 75% shading. Leaf size increased year by year because large seed corms Results and Discussion produced large leaves. Restricted leaf sizes under full Both species were damaged by full sunlight, sunlight was also reported in the case of A. konjac: the under which conditions necrosis and curling at either

the edge or the tip of the leaflets were observed, and in Table 2 Number of leaves of elephant foot yam and A. severe cases, the plants died. In A. muelleri, 50, 55 and muelleri plants grown under different shading 60% of the plants died in the first, second and third conditions over a three-year period years, respectively. However, only 25, 30 and 30% of elephant foot yam plants were lost due to damage by strong light in the first, second and third years, respectively. No damage was observed in the 25, 50

Table 1 Average monthly rainfall, daily mean temperature and relative humidity (RH) during the experiment

z Means followed by different letters within columns in each z Figures in parenthesis denote the minimum and maximum species are significantly different based on the least significant values. difference method at the 5% level. Santosa et al.: Amorphophallus growth under different shading levels 89

Table 3 Petiole and rachis length, corm fresh mass, and weight and number of cormels of elephant foot yam and A . muelleri plants grown at different shading levels over a three-year period

z Leaf 1 was the first to emerge .y Average of all the harvested corms including infected and flowering corms. x Means followed by different letters within columns in each year in each species are significantly different based on the least significant difference at the 5% level. wNo cormels were formed . leaf sizes increased by 30%when the light intensity was Watanabe (1985) reported that the ratios of the fresh reduced to 30-70% of full sunlight (Inaba, 1984). mass of daughter corms to that of seed corms were The fresh mass of elephant foot yam corms was 6.6, 4.8, and 3.9 in one-, two- and three-year-old corms, significantly smaller under full sunlight than under the respectively. The ratios decreased with the increase in 75% shading condition in the second and third years, the corm age in A. muelleri (2.8-3.3 and 1.3-1.6 in one- while that of the A. muelleri corms was significantly and two-year-old corms, respectively), but not in smaller under full sunlight than under shading conditions elephant foot yams (1.9-2.6 and 1.9-2.7 in one- and two- in all the three years (Table 3). Fresh mass of both year-old corms, respectively) in the present study. elephant foot yam and A. muelleri corms increased Furthermore, these ratios were higher in A. muelleri with the decrease in the light intensity: 75% shading than in elephant foot yams in the second year, but led to the formation of the largest corms. Pushpaku- lower in the third year. This was because the fresh mari and Sasidhar (1992) reported that the yield was mass of the corms increased exponentially with time in reduced by 66% under a 75% shading condition in the elephant foot yam plants, but linearly in the A. elephant foot yams. Such a response to shading might muelleri plants, regardless of the light intensity (data depend on the landraces used, as reported in the case not shown). Although a decrease in the light intensity of potato (Roberts-Nkrumah et al., 1986). Miura and increased the fresh mass of daughter corms in both 90 Jpn. J. Trop. Agr. 50 (2) 2006 species, the effect was more evident in A. muelleri. inflorescences in the third year, regardless of the light In elephant foot yams, although the fresh mass of conditions. However, in A. muelleri, 10% and 45% of the the cormels was not significantly different between the plants produced inflorescences in the third year under treatments in any year, the number of cormels was 50% and 75% shading conditions, respectively (Table 4). lower under 50% shading than under the control Because corms fetch a low price after flowering treatment in the first and third years, for unknown (Santosa et al., 2003), they should be harvested prior reasons. On the other hand, Douglas et al. (2005) to flowering. To produce corms with a commercial size reported that the number of A, konjac cormels increased in the absence of flowering, A. muelleri should be by 52% under 50% shading compared with full sunlight. harvested two years after the planting of one-year-old No cormels were formed in A. muelleri plants during corms, i.e., one year earlier than elephant foot yams. the experiments. Based on the pattern of increase in the fresh mass of Over the duration of the study period, some corms corms and flower induction, it is possible that the were found to be infected by pathogens such as physiological stage of A. muelleri plants is more advanced Rhizoctonia solani, Fusarium and Sclerotium sp. When than that of elephant foot yams. Goodwin et al. (1995) corms were infected, their infected parts became black reported that flowering in Blanfordia grandiflora and spongy, and the corms underwent rot. Although occurred less frequently in the plants grown under full the light intensity did not affect the occurrence of sunlight than in the plants grown under shade. In infected corms in elephant foot yams (Table 4), 50% of agreement with these results, A. muelleri plants did not the A. muelleri corms became infected under the produce inflorescences under full sunlight in the third control condition, while no infection was found under year. It is well known that the bulb size is the main the 75% shading condition. factor which determines the capacity to flower in In elephant foot yams, most corms reached a bulbous plants (Le Nard and De Hertogh, 1993). commercial size (950 g) or larger size in the third year Therefore, it is possible that flower induction depends under the 75% shading condition, whereas only 34% of on the corm size in Amorphophallus. However, it the corms reached such a size under the control remains to be determined whether differences in condition (Table 4). In A. muelleri, most corms reached flowering among the treatments are related to a commercial size by the end of the second year under differences in corm size, or result from the a direct 75% shading, and at the end of the third year under 50% effect of the light intensity on flower induction. shading (Tables 3 and 4). Acknowledgements In elephant foot yams, no plants produced This study was supported by the Core University Table 4 Percentage of infected corms, corms of marketable Program between the Japanese Society for Promoting size and flowering corms in elephant foot yams Science (JSPS), and the Directorate General of Higher and A. muelleri plants grown at different shading Education (DGHE), Indonesia. levels when measured on July 19, 2005 References

Caesar, K. 1980. Growth and development of Xanthosoma and Colocasia under different light and water supply conditions. Field Crop Res. 3: 235-244. Douglas, J.A., J.M. Follett and J.E. Waller. 2005. Research on konjac (Amorphophallus konjac) production in New Zealand. Acta Hort. 670: 173-180. Goodwin, P. B., P. Dunstan and P. Watt. 1995. The control of flowering in . Sci. Hort. 62: 175-187. Inaba, K. 1984. Effect of shading on leaf anatomy in konjak plants (Amorphophallus konjac K.Koch). Jpn. J. Crop Sci. 53: 243- 248.* Inaba, K and N. Chonan.1984. The effect of light intensity on the ultrastructure of chloroplasts in konjak (Amorphophallus z Corm surface infected by pathogens , e.g., Rhizoctonia solani konjac K.Koch). Jpn. J. Crop Sci. 53: 503-509.* and Sclerotium sp. y Size larger than 950 g. Jansen, P.C.M., C. van der Wilk and W.L.A. Hetterscheid. 1996. x Means followed by different letters within columns in each Amorphophallus Blume ex Decaisne. In: PROSEA 9: Plant species are significantly different based on the least significant yielding non-seed carbohydrates. (Flack, M. and F. Rumawas difference method at the 5% level. eds.). Backhuys Publ. (Leiden) 45-50. Santosa et al.: Amorphophallus growth under different shading levels 91

Le Nard, M. and A.A. De Hertogh. 1993. Botanical aspects of Roberts-Nkrumah, L.B., L.A. Wilson and T.U. Feruson. 1986. flower bulbs. In: The physiology of flower bulbs. (De Responses of four potato cultivars to levels of shade: 2. Hertogh, A.A. and M. Le Nard eds.). Elsevier (Amsterdam). Tuberization. Trop. Agric. 63: 265-270. 29-43. Santosa, E., N. Sugiyama, S. Hikosaka and S. Kawabata 2003. Miura, K. and K. Watanabe 1985. Effect of seed-corm age and Cultivation of Amorphophallus muelleri Blume in timber weight on the efficiency of corm tuberization in konjak forests of east Java. Jpn. J. Trop. Agric. 47: 190-197. plants (Amorphophallus konjac K. Koch). Jpn. J. Crop Sci. Santosa, E., N. Sugiyama, A.P. Lontoh, Sutoro, S. Hikosaka and S. 54: 1-7.* Kawabata. 2002. Cultivation of Amorphophallus paeoniifolius Pushpakumari, R. and V.K. Sasidhar. 1992. Yield variations of (Dennst.) Nicolson in home gardens in Java. Jpn. J. Trop. yams and aroids as influenced by shade intensities. Indian J. Agric. 46: 94-99. Plant Physiol. 34: 345-350. (*: in Japanese with English summary)

イ ン ド ネ シ ア に お け る 異 な る 遮 光 条 件 下 で の コ ン ニ ャ ク 属 植 物 の 生 育 と 球 茎 生 産

EdiSANTOSA・ 杉山信男*・ 中田美紀 ・李 温裕

東京大学大学院農学生命科学研究科

要 約Amorphophallus paeoniifolius (Dennst.) Nicolson(ゾ ウ コ ンニ ャ ク)とA. muelleri Mill.(ジ ャ ワ ム カ ゴ コ ン ニ ャ ク) は 樹 冠 下 で 栽 培 され る こ と が 多 い.こ れ らの コ ン ニ ャ ク属 植 物 は1年 生 の 球 茎 を植 えつ け て か ら通 常2な い し3年 後 に 収 穫 され る.し か し,こ れ ら コ ン ニ ャ ク属 植 物 の 好 適 栽 培 期 間 や 光 条 件 に つ い て は 明 らか に さ れ て い な い.そ こで,西 ジ ャ ワ, ボ ゴ ー ル に お い て 異 な る光 条 件(0%,25%,50%,75%遮 光 条 件)下 で3年 間,A. paeoniifoliusとA. muelleyiの 栽 培 を 行 っ た.球 茎 重 は,遮 光 条 件 に か か わ らずA. paeoniifoliusで は 年 と と も に 指 数 関 数 的 に 増 加 した が ,A. muelleriで は 直 線 的 に 増 加 した.葉 は 遮 光 程 度 が 強 い ほ ど大 き く な り,球 茎 重 も増 加 した.A. muelleriで は 約 半 数 の 個 体 は75%遮 光 条 件 下 で は植 え つ け 後3年 目 に 開 花 し た が,A. paeoniifoliusで は 開 花 す る 個 体 は な か っ た .75%遮 光 下 で 球 茎 が 商 品 と して 販 売 可 能 な大 き さ に な る の にA. muelleriで は 植 付 け後2年 か か っ た の に 対 し,A. paeoniifoliusで は3年 を要 した .こ れ らの 結 果 は両 種 と も 遮 光 条 件 を好 む 作 物 で あ る こ と,ま た 遮 光 条 件 下 でA. muelleriはA. paeoniifoliusよ り も1年 早 く収 穫 で き る こ と を示 唆 して い る. キ ー ワ ー ド:ア グ ロ フ ォ レ ス トリ ー,低 照 度,西 ジ ャ ワ,Amorphophallus muelleri, Amorphophallus paeoniifolius

*Corresponding author

〒113-8657東 京 都 文 京 区 弥 生 [email protected]