Abstract:
Beta vulgaris is one of the major vegetable crops cultivated in Kalpitiya, one of the significant
vegetable-growing regions in Sri Lanka. High daytime temperatures basically above 30°C reduce the
productivity of the crop. Farmers tend to cool down the cropping land using irrigation systems by
over-utilizing the groundwater, that causes the intrusion of seawater into the groundwater table in
the peninsula. In this context, the selection and recommendation of beet cultivars that can tolerate
higher temperatures could be a long-term solution to continue cultivation with limited water
utilization. The present study was conducted to screen three commercially grown beet varieties
(Maravilla Andina, Royal Red, and Red Ace) under in vitro conditions using two temperature levels,
34 °C for 8 h followed by 28 °C for 16 h provided in a growth chamber and the seedlings maintained
at 28 °C continuously (control). Murashige and Skoog medium was used as basal medium. The
factorial experiment was arranged in a Completely Randomized Design with 30 replicates. All the
cultures were maintained at 2500-3000 lux light intensity and 16 h photoperiod. After 45 days, the
number of leaves, number of fibrous lateral roots, shoot dry weight and total root dry weight were
recorded as growth parameters. The data were subjected to analysis of variance. The temperature
level has a significant effect on seedling growth (p<0.05), except for root dry weight and varieties
showed significant differences except for shoot dry weight (p<0.05). Among the varieties, Maravilla
Andina showed significantly higher growth performance under higher temperature level for shoot
and root dry weight (p<0.05) where the other two parameters had a significant reduction. All the
parameters were significantly reduced in Royal red. The same happened in Red ace except for
number of roots where a comparable performance was observed. Based on the results Maravilla
andina has more potential for tolerating higher temperature levels. However, further studies are
required for making a recommendation for the farmers.
