Cucurbit Genetics Cooperative Report 5:23 (article 11) 1982
Georgette Risser
Station de’Amelioration des Plantes Maraicheres, I.N.R.A., 84 40 Avignon-Montfavet, France
In 1979, we reported that cultivars differ when grown in nutrient solution maintained at low temperature, especially when radiation is low. For instance, in an experiment where root temperature was maintained at 12°C, yellowing and partial wilting were observed on ‘Persian’ small type while ‘Vedrantais’ retained green and healthy. In other experiments with high root temperature, interaction between genotype, root temperature and radiation was also observed.
Three cultivars were grown in a heated glass house during spring or summer in nutrient solution to examine these interactions more closley. The greatest difference between these two experimental conditions was light intensity (Table 1.) in experiment two, daily global radiation was more than twice the amount in experiment 1.
Table 1. Climatic characteristics of the experiments to study genotype environment interactions in muskmelon.
Experiment |
Time Period |
Daily Air Glass house Temp. |
Daily outside global radiation |
Tested Root Temp. |
|---|---|---|---|---|
| 1 | 10 Feb to 9 Mar 1979 | 21.5°C | 10.8 | 18, 22, 16, 30° |
| 2 | 19 Jun to 3 Jul 1980 | 23.5°C | 22.4 | 22, 26, 30, 34° |
Reactions of plants were quite different in the 2 experiments. During the spring (low light intensity, exp. 1) root temperature had a large effect on dry weight which differed with the cultivar (Fig. 1). When root temperature increased from18 to 30°C, dry weight of both ‘Freeman’s Cucumber’ and ‘Vedrantais’ increased. The increase was greater for ‘Freemans’. On the contrary, when root temperature was above 22°C, growth of ‘Persian’ was not so good: dry weight was less; foliage was dull; and at 30°C plants were in poor condition. During the summer period (high sunlight intensity, exp. 2) no significant differences were observed for cultivars or root temperatures (Fig. 1). When radiation is low, significant variation occurs between cultivars at the lowest and highest root temperature. Screening for root temperature adaptation requires, therefore, control of light intensity.
Literature Cited
- Mann, L. K. 1953. Honey bee activity in relation to pollination and fruit set in the cantaloupe (Cucumis melo). Amer. J. Bot. 40:545-553.
- Natti, T. A. and J.B. Loy. 1978. Role of wound ethylene in fruit set of I hand-pollinated muskmelons. J. Amer. Soc. Hor. Sci. 103:834-836.