Cucurbit Genetics Cooperative
Other Crop Genetics Cooperatives
Home About Membership Reports Gene Lists Conferences Links Search NCSU
Cucurbit Genetics Cooperative Report 7:49-50 (article 22) 1984

Effect of Methodology on Expression of Intercultivar Differences in Response to NaCl Stress in Melons

H. Nerson, H.S. Paris, Z. Karchi, Y. Burger, and M. Edelstein

Department of Vegetable Crops, Agricultural Research Organization, Newe Ya'ar Experiment Station, P.O. Haifa, Israel

Most vegetable crops are sensitive or moderately sensitive to salinity (1). Melons are classified as moderately tolerant (3) and are a potential crop for irrigation with saline water (2).

Sources of salt tolerance within a crop must be identified as the first step in a breeding program whose goal is to develop cultivars having higher salt tolerance. Several methods of screening and selection for salt tolerance have been evaluated for many crops (4).

Our objective was to compare responses of four melon accessions from diverse genetic backgrounds to salinity stress induced by three screening methods, and to relate these results to field test results. Accessions compared were the Israeli muskmelon 'Galia', the Israeli casaba 'Noy 'Amid', the European casaba 'Rochet', and a muskmelon introduction from Iran designated "Persia 202". The three screening methods were: (a) Seedlings were grown in 250 ml pots filled with fine gravel which were put in slightly larger pots containing Hoagland solution. At the first leaf stage (about ten days after emergence), NaCl at the rate of 10,000 ppm was added to the nutrient solution, which was renewed every other day. The pots were placed in growth chambers at two temperature regimes (day/night), 31C/23C and 23C/15C, with a 12-hour photoperiod. (b) Similar to a except that the pots were filled with a 4:1 (by volume) mixture of local silty loam:vermiculite at two salinity levels, 10,000 and 15,000 ppm, and (c) Seedlings were grown in larger pots (600 ml), in the greenhouse, with the same mixture as in b. NaCl at 15,000 ppm was introduced at the same developmental stage as in a and b but by daily application of 50 cc/pot in the nutrient solution.

Fourteen days after the beginning of salinization, plants were analyzed for growth, the data being presented in Table 1. Comparison of control results among the various methods revealed three different levels of seedling growth. The most favorable conditions were in c (larger pot, fertile medium, and high radiation) while the poorest were in a (small pot, hydroponic, inert medium, and relatively low radiation). Differences among accessions in response to NaCl stress were inconsistent among the three methods. For a given method, the most clear-cut difference occurred in c, where 'Rochet' was far superior to the other accessions tested.

Table 1. Effect of three methods of NaCl application on absolute growth (mg dry weight) and relative growth (% of control) of four melon accessions, 14 days after salinity introduction.

Accession

Salinity level (ppm NaCl)

Methodz

a

b

c

mg

%

mg

%

mg

%

Galia

0

203

 

437

 

1110

 

10,000

148

73 a

274

63ab

 

 

15,000

 

 

252

58 b

400

36 b

Noy 'Amid

0

201

 

555

 

1149

 

10,000

123

61 ab

380

68 ab

 

 

15,000

 

 

321

58 b

454

39 b

Persia 202

0

231

 

469

 

991

 

10,000

129

56 b

340

72 a

 

 

15,000

 

 

285

61 ab

368

37 b

Rochet

0

276

 

512

 

1109

 

10,000

162

59 ab

316

62 ab

 

 

15,000

 

 

304

59 b

695

63 a

zAverage of temperature regimes (see text). Mean separation in relative growth (%) columns by Duncan's multiple range test, 5% level.

The two casabas, 'Rochet' and 'Noy Amid', were compared in a field experiment for sensitivity to salinity. Expressed in terms of percent yield reduction, 'Rochet' was less sensitive to salinity than 'Noy 'Amid', consistent with the performance of these two cultivars in method c. This suggests that screening for salt tolerance should be conducted under as near to optimal growing conditions as possible. Such conditions would reduce confounding effects of various other environmental stresses and enable each accession tested to express its full salt-tolerance potential.

Literature Cited

  1. Maas, E.V. and G.J. Hoffman. 1977. Crop salt tolerance--current assessment. J. Irrig. Drain. Div., Amer. Soc. Civil Engin. 103:(1R2)115-134.
  2. Pasternak, D., I. Borovic, Y. De-Malach, and A. Davidson. 1980. Production of melons in the Negev Highlands with brackish water for summer and early autumn export. Hassadeh 61:133-138 (in Hebrew with English abstract).
  3. Shannon, M.C. and L.E. Francois. 1978. Salt tolerance of three muskmelon cultivars. J. Amer. Soc. Hort. Sci. 103:127-130.
  4. Shannon, M.C. 1979. In quest of rapid screening techniques for plant salt tolerance. HortScience 14:587-589.

Contribution No. 980-E, 1983 series, from the Agricultural Research Organization, Bet Dagan, Israel.

Home About Membership Reports Gene Lists Conferences Links Search NCSU
Department of Horticultural Science Box 7609North Carolina State UniversityRaleigh, NC 27695-7609919-515-5363
Page citation: Wehner, T.C., Cucurbit Genetics Cooperative;
Created by T.C. Wehner and T. Ng, 1 June 2005; design by C.T. Glenn;
send questions to T.C. Wehner; last revised on 30 November, 2009