Cultivar Trial of Melon (Cucumis melo L.)

Cultivar Trial of Melon (Cucumis melo L.) under TBIC Climatic Condition

Conducted by all participants

Report by Armando Dias Monteiro

Abstract

This trial was conducted at Tsukuba International Center (TBIC) from May 22, 2009 to July 27, 2009 in order to examine the characteristics of six melon cultivars including ‘Prince’ (the control) under TBIC climatic condition through of the growth, productivity, color, sweetness and marketability parameter of each cultivar.

Seedling of six cultivars namely ‘Prince’, ‘Prince PF’, ‘Resort’, ‘Papaya melon’, ‘Savanna’ and ‘Hami Uri’ were transplanted by 65cm between plants with two replications.

Plant height and leaf number of seedlings were recorded at transplanting stage. The harvest of all the cultivars carried out at approximately 47 days after flowering, on July 27, 2009 where the length and diameter till 13th node were measured. Number and weight of fruits per plot were also recorded.

Fruits characteristics such as color, diameter and brix were evaluated and sensory test by 54 panelists (37 males and 17 females) was carried out three days after harvesting.

In the beginning at 35 days after sowing, ‘Savanna’ and ‘Hami Uri’ were more vigorous than all cultivars accordingly their weight and number of leaves, even though the ‘Prince’ had the more number of leave.

‘Savanna’ showed the thickest vine diameter till the 13th node followed with ‘Prince’ and ‘Resort’. For vine length till the 13th node ‘Papaya melon’ had the longest value by 125.2 cm.

The ‘Hami Uri’ had the biggest yield and heaviest weight of fruit (2010.6 g), the second heaviest weight of fruit was ‘Savanna’ with 2009.5. ‘Prince PF’ produced more number of fruits (more than double of the ‘Hami Uri’). ‘Prince’ and ‘Prince PF’ had cracked fruit

Most of the plants were infected mainly caused by powdery and downey mildew by the time of harvesting. ‘Resort’ and ‘Hami Uri’ were less infected by this diseases. ‘Papaya’ was the more susceptible followed by ‘Savanna’. ‘Prince’ and ‘Prince PF’ had similar score. Verticilium damaged three plants of ‘Savanna’ in block 2.

The palatability test by gentlemen showed that ‘Resort’ and ‘Prince PF’ got better quality evaluation than ‘Prince’ in all criteria. ‘Hami Uri’ was evaluated better than ‘Prince’ only in appearance and sweetnes, all others cultivars were evaluated worse than ‘Prince’, and by ladies, ‘Prince PF’ was the one that showed better than ‘Prince’ in all criteria except for appearance.

Introduction

Cultivar trials are done for various crops in order to determine a superior one among or between cultivars. Selection of cultivars is done based on a number of parameters some of which include, color of fruit, appearance, aroma texture, and total soluble solids among others. The importance of parameters used depends on the type of crop. Melons for example, are selected with the important parameters that consumers give attention to, such as sweetness, colour, size and aroma of the fruits.

Melon is a warm season crop requiring high temperature (optimum temperature at 30- 32 0C for germination and 22- 25 0C for growing) and dry condition. With the advent of ‘Prince’ bred in 1962 in Japan, a lot of inter- and intra-varietal F1 hybrid cultivars were bred among the European netted melon (Cucumis melo var. reticulates), winter melon (var. inodorus), and rock melon (var. cantalupensis). ‘Prince’ was bred by crossing one strain of ‘Charetais’ from Europe and ‘New Melon’ from Japan. Its share in Japanese market accounted for about 80% in 1970, and it is still one of the popular cultivars in Japan. To cover for the shortfalls that ‘Prince’ had on disease resistance, some varieties including ‘Prince PF’ have been bred in Japan. Prince PF is resistant to Fusarium and Powdery mildew.

This study was conducted to examine characteristics of six melon cultivars including ‘Prince’ under TBIC climatic condition. The study focused on growth parameters such as thickness and length of the vines; productivity such as fruit weight, height, width, color, and sweetness; and marketability of each cultivar.

Materials and Methods

This trial was conducted in the experimental field of TBIC where 6 melon cultivars were planted: Prince, Prince PF, Savanna, Resort, Papaya melon and Hami Uri. The characteristics of each cultivar described in the seed company catalogues are in the Table 1.

Table 1. Characteristics of six cultivars described in the seed company catalogues

Name of cultivar

Company

Characteristics

C1 Prince Sakata Seed Co. A fruit size of 500-600g with green color. Good to harvest at 40 days after flowering. Brix 15-17.
C2 Prince PF Sakata Seed Co. A fruit size of 600g with green color. Slightly late maturity than ‘Prince’. Resistant to powdery mildew and fusarium wilt. More tolerant than ‘Prince’ to downy mildew and bacterial spot.
C3 Savanna Yamato Noen Co. A white color fruit with green stripe sized of 1,000-1,500g. Good to harvest at 50 days after flowering. Brix 15.
C4 Resort Sakata Seed Co. A fruit size of 800-900g with yellow color. Resistant to powdery mildew and fusarium wilt (race 0 and 2). Good to harvest at 40-45 days after flowering. Brix 15-16.
C5 Papaya melon Aisan Seed Co. Ltd. A yellow color fruit with green stripe sized of 800-1,000g with green color. Harvest at 40-45 days after flowering. Brix 15.
C6 Hami Uri Kaneko Seed Co. Ltd A fruit size of 1,300-1,500g with light orange color. Good to harvest at 50 days after flowering. Tolerate to powdery mildew. Brix 17.

The seeds of each cultivar were sown in seed-box on April 17 and potted in pots of 12 cm of diameter on April 29, 2009. Then five seedlings of each cultivar with two replications were transplanted by 65cm between plants on May 22, 2009. Table 2 shows fertilizer amount applied in the field. Compost was applied at the rate of 20 t/ha. The plants grew vigorously only with basal application probably due to the remaining nutrients from the previous cultivation. Top-dressing was not applied after establishment of the plants.

When melon plants developed secondary vines up to 30cm after pinching the main vine at the 5th to 6th node, two vines were selected for bearing fruits. All tertiary vines and hermaphrodite flowers below the 8th node of the secondary vines were removed. The fruits were mainly set on the 1st node of the tertiary vines grown from 8th to 15th of the secondary vines. Then tertiary vines were pinched at 3rd inter-node. Harvesting time was determined by the number of days after flowering. All the cultivars were harvested approximately 47 days after flowering, on July 27, 2009. Plant height and leaf number of seedlings were recorded at transplanting stage. Vine length till 13th node and vine diameter at 13th node were measured at harvesting time. Number and weight of fruits per plot were recorded to calculate average fruit weight and yield. Fruits characteristics such as color, diameter and brix were evaluated and sensory test by 54 panelists (37 males and 17 females) was carried out three days after harvesting. The characteristics of each cultivar were evaluated in comparison with ‘Prince’ as a standard cultivar in terms of appearance, sweetness, firmness, aroma/flavor and comprehensive evaluation.

Table 2. Fertilizer amounts applied (kg/10a)

Element

Basal

N

10

P2O5

20

K2O

10

Results and Discussion

Growth of seedlings

The growth of seedling varied greatly among each cultivar (Table 3). ‘Savanna’ showed the highest plant height by 18.7 cm among the cultivars. ‘Prince PF’ had smallest plant height by 8.7cm and lowest number of leaves by 3.3 among the cultivars. ‘Prince’ and ‘Prince PF’ had similar plant height but ‘Prince’ had greatest number of leaves by 5.7.

Table 3. Growth of melon plants at 35 days and 106 days after sowing.

Cultivar

Seedling stage

Harvesting time

Plant height (cm)

Number of leaves

Stem diameter at 13th node (mm)

Vine length till 13th node (cm)

Prince

8.8

5.7

11.0

102.3

Prince PF

8.7

3.3

9.5

100.5

Resort

10.3

4.0

10.3

113.7

Papaya melon

11.0

4.4

9.8

125.2

Savanna

18.7

4.7

12.2

93.5

Hami Uri

18.2

5.2

9.6

105.5

LSD (5%)

2.1

0.9

1.4

n.s.

Dry weight of seedlings in six cultivars showed the same trend as Table 3. ‘Hami Uri’ had the heaviest top weight among the cultivars and Prince PF had the lightest (Fig. 1 and Plate 1).

Plate 1. Growth of seedlings at 35 days after sowing.

Plant growth

The trial showed that the stem diameter and vine length till the 13th node gave some variation among the six cultivars (Table 3). ‘Savanna’ showed the thickest vine diameter followed with ‘Prince’ and ‘Resort’. For vine length till the 13th node ‘Papaya melon’ had the longest value by 125.2 cm, but there were no significant difference among the cultivars.

Disease infection

Verticilium damaged three plants of ‘Savanna’ in block 2. Most of the plants were infected mainly caused by powdery and downey mildew by the time of harvesting. Fig. 2 shows disease severity of each cultivar evaluated by 7 producers. ‘Resort’ and ‘Hami Uri’ were less infected by diseases. ‘Papaya’ was the more susceptible followed by ‘Savanna’. ‘Prince’ and ‘Prince PF’ had similar score.

Fruit weight and number

The result of this trial shows significant differences in number of fruits harvested, the averaged fruit weight, fruit shape and yield as compared with ‘Prince’ (Table 4).

The trial showed that the biggest yield was obtained in ‘Hami Uri’ because his heaviest weight of fruit (2010.6 g), the second heaviest weight of fruit was ‘Savanna’ with 2009.5 g, followed by ‘Papaya melon’ with 1233.7 g and ‘Resort’ with 1224.8 g, but ‘Savanna’ was not the second biggest in the yield, because even though ‘Prince PF’ had very small size compared with ‘Savanna’, ‘Prince PF’ produced more number of fruits (more than double of the ‘Hami Uri’), that was way it had the second bigger yield. It was observed clearly that average of fruit weight per plant seems to be directly related to fruit size and number of fruit per plan, and each cultivar has their size and number of fruit. Weight of fruit may also be affected by a certain extent with some environmental factors such as temperature and soil moisture. ‘Prince’ and ‘Prince PF’ had cracked fruit because their maturities were relatively earlier at 40 days after flowering than the other cultivars.

Table 4 Fruit characteristics of six melon cultivars

Size and shape of fruit

There were different kinds of fruit size and shape in six cultivars as compared to ‘Prince’ (Table 4 and Plate 2). ‘Savanna’ and ‘Hami Uri’ were the biggest of all; the ‘Savanna’ had the longest horizontal length and ‘Hami Uri’ was the longest vertical length. ‘Papaya melon’ and ‘Hami Uri’ had cylindrical fruit shape, while ‘Prince’, ‘Prince PF’, ‘Savanna’ and ‘Resort’ had rather oval fruit shape.

Papaya Melon

Hami Uri

Resort

Plate 2. Fruit size, shape and color of six cultivars tested.

Color of Fruit

The fruit showed differences in fruit and flesh color as compared to ‘Prince’ (Plate 2). Fruit and flesh color of ‘Prince PF’ showed green and lime yellow color, which were identical with

‘Prince’. ‘Resort’ showed yellow fruit color and white flesh color as similar to ‘Savanna’ and ‘Papaya melon’.

Brix

In this trial a hand refractometer was used to give an idea of the degree of sweetness indicated as brix value of given fruit (Table 4). Brix value showed differences between all six cultivars. All the fruits were harvested at once around 47days after flowering. Brix values were generally low for all the cultivars because disease infection at the period of fruit maturity to harvesting discouraged photosynthesis in the plant. Especially ‘Savanna’ and ‘Hami Uri’ had lower brix value, 7.1 and 9.8 respectively due to their requirement in longer maturity periods around 50 days after flowering. The measurement showed that ‘Prince PF’ produced the sweetest fruit which was 14.5 followed by ‘Resort’ with 12.4, and ‘Prince’ with 12.2 brix value.

Palatability

The palatability test by gentlemen showed that ‘Resort’ and ‘Prince PF’ got better quality evaluation than ‘Prince’ in all criteria (Fig. 3). ‘Hami Uri’ was evaluated better than ‘Prince’ only in appearance and sweetness. The other cultivars could not compete with ‘Prince’ in any criteria. Gentlemen preferred more to ‘Resort’ and ‘Prince PF’ as compared with ‘Prince’.

The result of palatability test by ladies was slightly different from that by gentlemen (Fig. 4). Ladies evaluated more severely than gentlemen so that the scores were extremely low. ‘Prince PF’ showed better than ‘Prince’ in all criteria except for appearance. Ladies preferred to ‘Prince PF’ as compared to ‘Prince’.

Conclusion

It indicated that there were no significant differences in yield among the cultivars. ‘Prince PF’ had higher brix value and positive scores on fruit quality evaluated by both gentlemen and ladies as compared to ‘Prince’. Therefore ‘Prince PF’ has a potential to make a change on penetrating market and consumption with its excellent quality. ‘Resort’ also can benefit farmers/producers as it is tolerated to diseases in the field and to make diversification in market.

It is important and good idea to conduct cultivar trials on vegetable crops first, before starting cultivation to meet the market demand and profitability. This can help improve the life standard of small scale farmers with minimum risks and increase sustainability of production.

References

Chang, L. C. 1972. Melon: Harvest Queen. Vegetable Growing. Agricultural Technical Group to Vietnam.

Robinson, R.W and Decker-Walters, D.S. 1997. Cucurbits: Crop Production Science in Horticulture, Volume 6. CAB International, New York.

Training Report, JICA/ TBIC, September 2008: Horticultural Crop Cultivation and Extension for Africa.

Plate 3. Two laterals vines developing

Plate 4. Management of melon

Plate 5. Disease symptom (downey and poldery mildew) at harvesting time

Plate 6. Harvest of melon fruit

Plate 7. Measuring the size of melon fruit

Plate 8. Sensory test of melon fruit

Prince PF

Prince

Savanna

Hami Uri

Prince PF

Resort

Savanna

Papaya Melon

Prince