J. Hort. Sci. 
Vol. 1 (1): 55-57, 2006 

Studies on the extent of genetic contamination in seed production of 
ridge gourd (Luffa acutangula Roxb.) 

K. Padmini and L. B. Naik 
Section of Seed Science & Technology 

Indian Institute of Horticultural Research 
Hessaraghatta Lake Post, Bangalore-560 089, India 

E-mail: kpadmini@iihr.emet.in 

ABSTRACT 

Studies were conducted during 2002-2005 (Rabi season) to evaluate the extent of genetic contamination in 
round fruited ridge gourd (recessive) vehen grown for seed production under open field conditions. The round 
fruited ridge gourd was sown at 200 m, 400 m, 600 m and 800 m distance from Arlia Sumeet (long fruited) which 
acted as the local marker (dominant). The highest percentage of genetic contamination was recorded at a distance 
of 200 m from the contaminator (Arka Sumeet) (28.62% and 88.1%, respectively, in the years 2003 and 2005). 
It was also observed that there was a gradual reduction in contamination level with increasing distance from 
28.62 to 17.44% at 600 m distance in 2003 and 88.11% at 800 m to 74.23% in 2005. The lowest percentage of 
contamination was recorded at the highest isolation distance (at 600 m, 17.44% in 2003 and at 800 m, 74.24% in 
2005), although it is not within the prescribed maximum permissible limit of genetic contamination (1 and 2% 
for foundation and certified seed respectively). In the present study, in all the isolation distances studied, the 
level of contamination is well above the permissible minimum seed certification standards (99 and 98 % genetic 
purity for Foundation and Certified seed respectively). Hence, any reduction in the isolation distance from the 
prescribed (800 m) isolation would drastically affect the genetic purity of ridge gourd for seed production under 
open field conditions. 

Key words: Cucurbits, genetic purity, isolation, ridge gourd, seed production 

INTRODUCTION CwcMmw spp ( Rosa, 1924). Growing different ridge gourd 
T j - - i j * u u - u * J f »ui varieties in the vicinity would enhance the chance of 
India IS ranked as the highest producer or vegetables . . ^ ,^. , , , „ „ „ , , , . 

. ., , j .̂ r nn n- .- • /co™iv Contamination. Tumwar and Singh (1988) have recommended 
in the world accounting for 90 million tonnes in 6.2 million ,^^„ , ^^^ . , . ,. r ,^ 
. ^ J . ^Xr,~ rî  /TT • c e T A- 1000 m and 500 m isolation distance for Foundation and 
hectare area dunng 2003-04 (Economic Survey of India, ^ . ^ , , , . ^ . , . . , ^ 
2004-05). The projected hybrid and open pollinated (OP) ^^""'^'"^ f"^. P'-oduction of ndge gourd, respectively. The 

, . \ c J u innc • u- u * / i n n c prescribed minimum Seed Certification standards for all 
seed requirement for gourds by 2005 is highest (1012.5 ^ . . . , . „,̂ ^ , .^^ • , • 

, -imc » \.- I \ J • •u cucurbits, m general, is 800 m and 400 m isolation distance 
tonnes and 2025 tonnes, respectively) compared to other . ^ , . , .^ , , , . . , 

* ui /Au J . 7 ^nnA\ T, • • * 11- • J for foundation and certified seeds production, respectively 
vegetables (Ahmed e? a/, 2004). Being insect pollinated, ^̂  , . ^ „ . ,„„^^ ^ , ^ ,. . ^r^ „ 

,.^ . • 1 ..• J-.. . ^ (Agarwal and Dadlani, 1987). In the earlier studies of Radha 
cucurbitaceous crops require an isolation distance to prevent i, r , , , . , . 1 ^ „ , / . , . , . 

j , ^ . , II- *• KnshnaMaiya e? a/(2001) in cotton, which is often a cross 
outcrossing in seed production by open pollination „. , ^ . , . m- • • . 
/D u- innr. c- u j T-> \. ->r>nc\ T I *• poIIinatcd crop, 6m isoMion was Sufficient as against the 
(Robinson, 1999; Singh and Dasgupta, 2005). Isolation ^ ., , . v , .~ . , , f^„ 
,. ^ . J J . • • • •» .. * prescribed minimum seed certification standards of 50 m and 
distance m any seed production is a pre-requisite to prevent K^ ^ r , • . ,- , , • , o-

.̂ , u • 1 • * / 11- »• f *u 30 m tor foundation and certified seed respectively. Since a 
either mechanical mixture /cross pollination for the , . , . ^ , f . , - ^ , . 

j ^ . cu A ic J . - - / 4.-e- A A highproportionof natural crossing occurs in ndge gourd, it 
production of breeder/ foundation/ or certified seeds. & f f . , . , ° . . , . V 
TT ,̂ . . .,, ,̂ ., J . . J n e c e s s i t a t e s i s o l a t i o n b e t w e e n v a r i e t i e s / g o u r d s for 
However, this varies with the crop, wild species, wind . „ . . ^ . . .'^ . 
, , , . J u - 1 1 * - c A T ^ maintenance of genetic punty. There is no information on 
breaks, b a m e r s and geographical location of seed plot, , ,. , , r r/ • • •, • , ^ ,-

the distance needed tor effective isolation under Indian 

etc., which are crossable with the crop under study. 

Ridge gourd is a cross - pollinated croj 
pollination is effected mainly by honey bees. Under n 
conditions, pollination by honey bees is upto 85-95% in distance. 

conditions. Hence, the present study was undertaken to 
Ridge gourd is a cross - pollinated crop and determine genetic contamination in seed production of ridge 

pollination is effected mainly by honey bees. Under natural gourd under open field conditions, so as to reduce the isolation 

mailto:kpadmini@iihr.emet.in


Padmini and Naik 

MATERIAL AND METHODS 

A field experiment was conducted at Indian Institute 
of Horticultural Research, Bangalore, in the Rabi season 
of 2002 to 2005 to facilitate natural crossing between round 
and long fruited ridge gourd. The recessive seed parent 
(round fruited type) was sown in isolation from other 
varieties/ gourds to avoid cross pollination. The different 
isolation distances used were 200 m, 400 m, 600 m and 
800 m from the contaminator /marker, Arka Sumeet 
(dominant long fruited type). These distances are less than 
the prescribed 800 m for cucurbits in obtaining foundation 
seeds. It was ensured that there were no physical barriers 
upto 8{X) m to facilitate natural crossing during Rabi 2002 
and 2004. The crop was raised using the recommended 
package of practices. Seeds of ridge gourd collected at 
various isolation distances from 200 m,4(X) m,600 m and 
800 m from the contaminant plot (round type ) were 
extracted and used for genetic purity evaluation by 
conducting field grow-out tests (GOT) during October 
2003 and October 2005 following standard procedures 
(Agarwal, 1993). The crop was sown in a randomised block 
design with seven replications per treatment. 

The extent of genetic contamination in seed crop 
was recorded based on the number of plants with long fruits 
in the progeny and expressed as percentage. Statistical 
analysis of data was done using Analysis of variance 
(ANOVA) for various isolation distances after data were 
subjected to angular transformation. 

RESULTS AND DISCUSSION 

Data on frequency of contaminants and extent of 
genetic contamination in the progeny of seed crop (round 
fruited recessive type) at various isolation distances from 
the contaminator, Arka Sumeet (long fruited dominated 
type) are given in Tables 1 and 2, respectively. Results 
revealed that contamination in the progeny of round fruited 
type decreased with increasing isolation distance from the 
contaminator.The highest percentage of genetic 
contamination/outcrossing was recorded at a distance of 
200 m from the contaminator (28.62% in 2003 and 88.11% 
in 2005). The lowest percentage of contamination was 
recorded at the highest isolation distance (at 600 m, 17.44% 
in 2003 and at 800 m, 74.24% in 2005), although it is not 
under the prescribed maximum permissible limit of genetic 
contamination. Statistical analysis of the transformed values 
of percentage of genetic contamination revealed that there 
were no significant differences among the various isolation 
distances studied for the extent of genetic contamination 
in the years 2003 and 2005. 

Table 1. Frequency of round and long fruited types in the progeny 
of round fruited ridge gourd at various isolations (grow-out tests) 
Isolation 
distance 

(m) 
2003 
200 
400 
600 
800 

2005 
200 
400 
600 
800 

Number of 
round fruited 

types 

173 
188 
158 

* 

11 
13 
15 
34 

Number of 
long fruited 

types 

59 
49 
33 

* 

86 
59 
58 
80 

Total number 
of plants 

per treatment 

232 
237 
191 

* 

97 
72 
73 

114 

*No fruit set observed 

Table 2. Extent of genetic contamination at various isolation 
distances in ridge gourd 

Isolation distance 
(m) 

200 

400 

600 

800 

CD (0.05) 

Genetic contamination (%) in the 
progeny of round fruited ridge gourd 

2004 
28.62 

(31.49)* 
20.14 

(26.43)* 
17.44 

(24.06)* 
_ 

NS 

2005 
88.11 

(69.80)* 
83.51 

(66.01)* 
79.04 

(63.23)* 
74.23 

(59.47)* 
NS 

: Angular transformed values; - No fruit set was observed 

The present study revealed that as the isolation 
distance increased from 200 m to 800 m, per cent 
contamination in the progeny of round fruited ridge gourd 
decreased. The minimum genetic purity standards for 
Foundation and Certified seed are 99% and 9 8 % , 
respectively. Cross-pollinated vegetable seed crops exhibit 
higher degree of variation as compared to self-pollinated 
vegetables. Also, genetic contamination in cross- pollinated 
vegetables affects in such a way that any specific character 
bred into a variety is likely to be lost (Prem Singh Arya, 
1999). In the present study, although there were no 
significant differences between the isolation distances it is 
risky to reduce the prescribed isolation distance below 800 
m. as the level of contamination is well above the 
permissible minimum seed certification standard. 
Differences in the levels of genetic contamination between 
the years 2003 and 2005 could be attributed to a relative 
abundance of pollinators which is variable based on the 
attractiveness to the adjacent field crop. Hence, any 
reduction in isolation distance from the prescribed 800 m 
would drastically affect the genetic purity of ridge gourd 

/ Hort. Sci. 
Vol. 1 (1): 55-57, 2006 

56 



Seed production in ridge gourd 

for seed production under IIHR conditions at Bangalore. 
Thus, there is a need to standardize the isolation distance 
to ensure the genetic contamination of round fruited ridge 
gourd is well within the permissible limits so as to maintain 
the minimum genetic purity standards for Foundation and 
Certified Seed production under Bangalore conditions. 

REFERENCES 

Agarwal, P. K. 1993. Handbook of seed testing. Ministry 
of Agriculture. GOI, New Delhi. 130p. 

Agarwal, P. K. and Dadlani, M. 1987. Techniques in seed 
scienceandtechnology of Ridge gourd. South Asian 
Publishers, New Delhi. 190p 

Ahemed, N, Khan,S. H and Baseerat. 2004. Hybrid 
vegetables: A Historical perspective, preset status and 
future prospects, pp 1-9. In: Recent advances in 
hybrid seed production of important vegetables. Sher-
e-Kashmir University of Agricultural Sciences and 

Technology, Srinagar (India), 
Economic Survey of India. 2005. Ministry of Agriculture 

and Cooperation, New Delhi. http:// 
indiabudget.nic.in 

Prem Singh Arya. 1999. Vegetable seed production-
principles. Kalyani Publishers, pp 78-82. 

Radha Krishna Maiya, Basave Gowda, Shekhara Gouda, M. 
and Khadi, B.M. 2001. Isolation distance in cotton 
(Gossypium arboreum). Seed Res., 29:245- 247. 

Robinson, R.W. 1999. Rationale and methods for producing 
hybrid cucurbit seed. J. New Seeds, 1:1-47. 

Rosa, J..T. 1924. Pollination and fruiting habit in the 
cantaloupe. Proc. Amen Soc. Hort. Sci., 21:51. 

Singh, RK and Das gupta, S. K. 2005. Hybrid Loofah. / 
 Ĥ' Seeds, 6:2-3 

Tumwar N .S. and Singh S.V. 1988.1ndian minimum seed 
certification standards. Central Seed Certification 
Board, New Delhi. pp:221-222. 

(MS Received 5 April, 2006 Revised 19 June, 2006) 

J. Hort. Sci. 
Vol. 1(1): 55-57. 2006 

57 

http://