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RESEARCH ACTIVITIES ON YARDLONG BEAN AT BRAC AGRICULTURAL RESEARCH & DEVELOPMENT CENTRE (BARDC), BANGLADESH

By Dr. Sitesh Ch. Biswas

Yardlong bean is an important leguminous crop of the tropical countries and it is a very common vegetable cultivated by the farmers of the South Asian countries including Bangladesh. Farmers of Bangladesh used to cultivate different types of land races or local varieties of yardlong bean a few decades ago and those varieties were not only low yielding, these were almost seasonal type and also susceptible to diseases. Fruits of these local varieties were relatively shorter and these varieties were usually cultivated in the homestead areas. With the rapid advancement of commercial agriculture in Bangladesh now a good no. of commercial growers are cultivating improved varieties of yardlong bean which are long fruited type and relatively higher yielding as well. Since yardlong bean is a warm season crop, most of the farmers usually cultivate yardlong bean as a Kharif crop although the availability of few local variety/varieties of yardlong bean is/are not uncommon in the early part of the winter i.e. in the off-season. Plants of the improved varieties are usually grown through the support of “A” structured longer erected sticks to produce better yield. It can be mentioned here that in Bangladesh, during the early part of the summer Nor‘Wester wind poses risk to yardlong bean cultivation as the high speed wind usually cause damage to the yardlong bean crop by breaking the erected sticks usually used to provide support to the yardlong bean plants. Yard long bean is a protein rich nutritious vegetable and pink coloured yardlong bean has more health benefits as these varieties are the rich sources of ‘anthocianin’- a very common type of antioxidant. Basically yardlong bean is a relatively short duration crop and its vigorous plants can survive easily in the poor quality soil of marginal type lands as well. Owing to its shorter crop duration it easily fits into the existing cropping pattern of Bangladesh. Due to its hardy nature and relatively shorter crop duration, yardlong bean is also considered as a ‘bioremediation crop’ as it absorbs heavy metal from the lands highly infested with heavy metals. Moreover, as yardlong bean is a leguminous crop, it increases soil fertility by fixing atmospheric nitrogen. And sometimes it is also cultivated as a green manure besides its main cultivation as vegetable crop. Trellis cultivation or cultivation of yardlong bean through staking though very common, is a costlier and laborious option. On the other hand, cultivation of semi-indeterminate type yardlong bean variety without trellis or staking is more easy and relatively cost saving option. Although fruits of these semi indeterminate type yard long bean varieties are relatively shorter yet these fruits can easily be transported to the markets by arranging them in box type containers. Even more for exporting purpose too much long size fresh yardlong bean fruits are undesirable rather relatively shorter fruits can be accommodated easily in the transportable cartoons. And as these varieties can be grown without erected sticks or trellis; intercropping with other crops is also possible. In Bangladesh deep green, pink and whitish green these 3 types

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of tender yardlong beans are sold in the market and mixing pink coloured beans with green or whitish green increase the selling rate of yardlong bean in the fresh vegetable market. The tender fruits of yardlong bean are usually consumed as stir fried food item or used in the soup. Fleshy type yard long beans are generally used in the curry while less fleshy type beans are used as stir fried food item. Traditional type improved type high yielding yard long beans can be grown in the home gardens along the fence of the garden and these climbing plants usually produce sufficient fruits at maturity while non climbing types can be grown both in the home garden as well as in the roof garden. Since Among the different long fruited type varieties, ‘Kegornatki’ is otherwise an excellent variety in terms of yield and fruit quality but this particular variety suffers badly by the Bacterial brown spot or common leaf blight disease during the fruit maturity period. On the other hand BARDC developed lines are tolerant to common leaf blight disease. Again, since yardlong bean itself is a wet tolerant vegetable, its availability in the kitchen market can be ensured by its careful cultivation in the monsoon season. Considering the increasing demand of good quality yardlong variety in the domestic as well as in the foreign market BRAC started its yardlong bean variety development during the year 2003-2004 and few improved yardlong lines have been developed at BRAC Agricultural Research and Development Centre which has been presented in this short communication ( Table.1).

Table. 1. Brief history of the development of the promising yardlong bean lines. Sl. no

Code no.

Name of the lines

100- seed wt. (gm)

No. of seeds/Kg

Breeding technique applied

No. of crossing attempted

Year of crossing or other technique applied

Name of the promising plants/stocks

Remarks

01 YLB 06 P12 15.36 6510 Crossing between Local X Jijiang

3. (LXJ), (LXK) & (KXJ)

2002 Plant no. 12 from the F3 population

Longer green fruits with good fruit bearing habit; fruits per plant 18-20.Tolerant to common leaf blight disease which is prevalent in the popular variety ‘Kegornatki’.

02 YLB 10 Natun 14.76 6775 Crossing between Kegornatki X P12

Kegornatki X P12

2010 Longer green fruits with good fruit bearing habit.

03 YLB 04 Shova-1 10.85 9232 Crossing between P12 (green fruited) X Local Pink

Local Pink Fruited X P12 and P12 X Local

2005 D. Red (III) plant Longer pink coloured fruits with good fruit bearing habit. High

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Fruited Pink Fruited yielding & tolerant to leaf miner. More tolerant to fungal diseases.

04 YLB 05 Shova-2 14.43 6930 Crossing between P12 (green fruited) X Local Pink Fruited

Do 2005 D. Red ( P1/1) Longer pink coloured fruits with good fruit bearing habit. High yielding & tolerant to leaf miner. Less tolerant to fungal diseases.

05 YLB 02 BRAC-35

15.86 6309 Introduction followed by selection

- 2013 *HNF stock Early season type longer light green coloured fruits with good fruit bearing habit. Higher yield & cold tolerant.

06 YLB 03 BRAC -03

14.82 6747 Introduction followed by selection

- 2013 *HNF stock Early season type but a bit late than BRAC-35. Longer whitish green coloured fruits with good fruit bearing habit. Cold tolerant line.

07 YLB 07 TR-1 15.96 6265 Introduction followed by selection

- 2014 *HNF stock Plants are less compact type and lower no of branches. Longer whitish green coloured fruits with moderate fruit bearing habit. Relatively cold tolerant

08 YLB 08 TR-2 16.77 5964 Introduction followed by selection

- 2014 *HNF stock Longer whitish green coloured fruits with good fruit bearing habit.

09 YLB 12 Greenish BRAC-

15.86 6309 Slection from BRAC-35

- 2015 Plant produced greenish white

Longer greenish white coloured fruits with

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35 coloured fruits good fruit bearing habit. Cold tolerant

10 YLB 09 BRAC -35 (Red)

14.76 6375 Slection from BRAC- 35

Plant produced reddish coloured fruits

Longer reddish coloured fruits with good fruit bearing habit.

11 YLB 11 YLB 01/15

13.23 7558 Selection - 2016 *HNF stock with good quality fruits

Semi-indeterminate plant having relatively short size fruits. Cold tolerant line. It can be cultivated without any stick. Yield 6.79 Mt per acre.

HNF Stock = Higher no. of fruits.

Important Features of BARDC Developed Lines

i) P12 : It is a green fruited advance line (Fig.1). It was isolated as plant no. 12 from the F3 population derived from the crossing between Local X Jijiang (an introduced white coloured exceptionally long and broad fruited variety). Its vigorous plants flowered at 42 DAS. Picking of fruits can be started from 49.00 -50.00 DAS. Its green colored fruits were longer (around 60.50 cm) and also fleshy (diameter-1.10 cm). Individual fruit wt. was recorded 30.00 gm. It was found to be tolerant to leaf blight disease which is prevalent in the commercial variety ‘Kegornatki’. Prolonged fruiting is one of the major characteristics of this line. Its multilocational trial has been conducted during the year 2012 at Dinajpur farm and found to be a well adapted line. Its yield was recorded as 25 Mt/ha. In an experiment yield of P12 was recorded as high as 378.42% than Lal Teer variety ‘ Lal beni’. Yield per acre 8.20 Mt.

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Fig.1. Fruits of the P12 line.

ii) Natun (KGN X P12): This advance line has been developed through the hybridization between the most popular green long fruited variety “Kegornatki” and the BARDC developed line P12 (Figs. 2 & 3) . Its plants were vigorous and matured within 37 days after the sowing of seeds. Fruits were long (fruit size- 46.88 X 0.89 cm) deep green and its fruit harvesting could be started from 43 days after seeding. Crop duration of ‘Natun’ was recrded as 63-64 days. It also exhibited tolerance to virus and leaf blight disease. Yield per acre 4.13Mt.

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Fig. 2. Fruit bearing plants of the BARDC developed line ‘Natun’.

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Fig.3. Comparison between ‘Kegornatki’ & ‘Natun’.

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iii) Shova -1: It is an anthocianin rich pink fruited variety (Fig. 4). Originally it was developed through the hybridization between P12 (green fruited) X Local Pink Fruited stock. To obtain a high quality red fruited yard long bean variety a locally available low yielding short size pink fruited variety was crossed with the good quality high yielding BARDC developed line P12 and through selection a line with desirable type pink coloured long fruited having good fruit bearing habit was isolated. This high yielding line was also characterised by excellent plant vigour, longer fruits (fruit length-48.80cm.) and had good fruit shape and size. Its production was found also to be relatively better than green fruited varieties in the monsoon season. This particular line was found to be tolerant to leaf miner attack. Yield per acre 5.31 Mt.

Fig.4. Fruits of Shova-1. Fig.5. Fruits of Shova-2.

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iv) Shova -2: It is also a high yielding and anthocianin rich pink fruited variety (Fig. 4). Almost very much similar to Shova -1 and has been developed from the same cross. More deep green and bigger leaves compared to popular variety’Kegornatki’ and tolerant to common blight disease. It is also tolerant to leaf miner attack. More yield than Shova-01. Yield per acre 6.84Mt.

v) BRAC-35 : It has been developed from an introduced exotic germplasm. Extra early season type line having longer light green coloured fruits (Figs.6-9). Very fast growth and it matures just within 30-31 days. Fruit picking can be started at 40-41 days. Moderate foliage, prolific bearer and its fruits are less fibrous and very soft. Its fruits have also more fleshy part compared to other lines and this is why fruits are heavier and more tasty. It looks more tender at the marketable stage. Almost 43.96% increased length & 96.02% higher fruit wt. than ‘Kegornatki’ was recorded in BRAC-35 fruit. It has also the potentiality to tolerate moderate cold (Figs. 6) and this cold tolerant line can give satisfactory yield during the early part of the winter and can be successfully cultivated during the early part of the spring season practically when there is no yardlong beans in the market(Figs.7). Per acre yield of this line has been recorded as 6.77 Mt.

Fig.6. Cold tolerant nature of BRAC-35 in the early part of winter Fig.7. Cold tolerant nature of BRAC-35 in the early part of (right) and check variety (left). spring (right) and check variety (left).

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Fig.8. Performance of BRAC 35 in the Kharif-2 season. Fig.9. Performance of BRAC 35 in the Kharif-1 season.

vi) BRAC-03: This line was also developed from an exotic germplasm. Plant growth is very much similar to BRAC-35 but matures later than BRAC-35 (Figs.10). Early season type line having whitish green longer fruits. Relatively less foliage with moderate fruiting habit. Fruit length is around 50-51 cm. and had average fruit wt. between 18-19 gm. It can also be cultivated as short duration type light green fruited yardlong bean. Yield per acre 5.03Mt.

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Fig.10. Performance of BRAC 03 in the Kharif-1 season. vii) TR-01: It was developed from an exotic germplasm (Figs. 11 & 12). Relatively short duration type. It has got less foliage and the fruits are greenish white. Prolific bearer and its tender fruits are long, soft and tasty. First picking can be started from 46 days. Fruit length 61-65 cm and fruit wt. 27-30 gm. per fruit. Fruits are more or less uniform and yield per acre 3.39 Mt.

Fig. 11. Fruit bearing plants of the BARDC developed line ‘TR-01’. Fig. 12. Fruits of the BARDC developed line ‘TR-01’.

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viii) TR-2: This line was also developed from an exotic germplasm. It is also an early season type line having greenish white longer ruits (Figs.13&14). Prolific bearer and tender fruits are soft and tasty. Vigorus plants but had less foliage. Less fruiting than TR-1. Picking can be started from 43 days after sowing. Fruit length- 60-65cm. and fruit wt. 25-27 gm per fruit.Yield per acre 3.51 Mt.

Fig. 13. Fruiting plants of TR-02. Fig. 14. Fruiting plants of TR-02.

ix) Dwarf Type : All season type advance line and can be cultivated as a year round crop. Semi-indeterminate type plants and most of its branches are developed around the base of the plant (Fig. 15). Plants usually mature 40-45 days and 1st picking can be started from 50 -55 days after sowing (Table.2). Good fruit bearing habit and 23-24 fruits are produced by each plant. Uniform stringless medium size fruits (Fruit length- 27.00 -31.00 cm) are soft and palatable. Yield per acre 7.00 -7.50 metric tons. It can be cultivated like other type of field crops and it does not require any staking or trellis for its cultivation. Also suitable for cultivation as intercrop. Characteristics of newly developed all season type yardlong bean:

1. All season type variety and can be cultivated as a year round crop. 2. Semi-indeterminate type plants and most of its branches are developed around the base of the plant. 3. Plants usually mature 40-45 days and 1st picking can be started from 50 -55 days after sowing. 4. Good fruit bearing habit and 23-24 fruits are produced by each plant.

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5. Uniform stringless medium size fruits (Fruit length- 27.00 -31.00 cm) are soft and palatable. 6. Yield per acre 7.00 -7.50 metric tons. 7. It can be grown as other field crops and it does not require any staking or trellis for its cultivation. 8. Also suitable for cultivation as intercrop.

Table.2. Evaluation of all season type (YLB 01/15) yardlong bean in different seasons of the year 2016-17 ( combined report). Season Seeding

date Plant hei-ght (cm)

No. of bran-ches/ plant

Total no. of clusters /plant

Total no. of fruits/ plant

No. of fruits/ cluster

Fruit length (cm)

Fruit wt./fruit (gm)

Fruit dia-meter (mm)

Fruit colour

Days to 1st flower-ing

Days to 1st pick-ing

Days to 50 % pick-ing

Total no. of pick-ings

100-seed wt. (gm)

Fruit yield /acre (Mt)

Disease reaction

Rabi’ 2016

23.10.16 57.20 - - 12.60 2.80 27.40 10.33 - Green 45.00 64.00 - - 4.99 Tolerant to virus & other major

disease

Kharif’ 2017

28.02.17 34.20

4.50

10.00 20.10

- 31.00 15.20 9.60 Green 53.00 63.00 - - 6.78

Fig.15. Semi indeterminate all season type yard long bean (exhibiting no climbing habit).

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Fig.16. Comparison between fruits of semi indeterminate all season Fig.17. Comparison between fruits of semi indeterminate all season type yard long bean & common longer green fruited bean. type yard long bean & longer red fruited bean. .

Fig.18. Comparison between fruits of all season type yard long bean and other beans including whitish green fruited beans .

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Conclusion

Yardlong bean is a very popular leguminous vegetable of Bangladesh. Its different coloured tender fruits are used either as stir fried food item or in the soup or in curry. Since it can be grown almost round the year there is very good market of yardlong bean in this country and now a days commercial vegetable growers are cultivating yard long bean widely as they earn a big profit by selling this vegetable in the kitchen market. Considering the importance of yardlong bean BRAC started research work on yardlong bean nearly 2 decades ago and so far developed a good no. of advance lines which are likely to be released for commercial cultivation in the coming years. If these improved lines are released, these varieties will increase the yard long bean production in Bangladesh significantly.

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Address:

Dr. Sitesh Chandra Biswas Progarm Specialist (Vegetable Research) BRAC Agricultural Research & Development Centre Jogitala, BRRI, Joydebpur, Gazipur-1701 Bangladesh Phone: 9294207 Mobile:+88 01730349845 E-mail: sitesh.cb@brac.net or, siteshchbiswas@yahoo.com