Effects of salinity stress on vegetative growth of chrysanthemum [Dendranthema glandiflora Kitam.]

Estimates show that about 10% of the world’s arable land is affected by salinity. Since water is increasingly becoming a very limited resource in many parts of the world, there is need to explore the potential of using saline water in irrigated agriculture. A greenhouse experiment was carried out to determine the highest level of salinity, which chrysanthemum plants can tolerate in order to reduce use of fresh water in agriculture. The objective of the experiment was to determine the effects of different levels of sodium chloride [NaCl] on the vegetative growth of chrysanthemums. There were five treatments which consisted of irrigation water containing 0 [control], 2, 4, 8, and 16 dS/m NaCl. The treatments were laid out in a randomised complete block design [RCBD]. Results showed that the highest plant height [54.2 cm] was obtained from chrysanthemums irrigated with water containing 2 dS/m NaCl. The lowest plant height [35.6 cm], root length [21.2 cm], shoot fresh mass [203.5 g], shoot dry mass [48.0 g], and root dry mass [2.0 g] at 8 weeks after transplanting [WAT], were obtained from chrysanthemums irrigated with water at 16 dS/m NaCl. An increase in salt concentration above 4 dS/m resulted in a corresponding reduction in all parameters determined. There was more than four-fold reduction in root fresh mass between the control and plants irrigated with 16 dS/m NaCl. There was an almost 15 fold reduction in root dry mass between the control and plants irrigated using 16 dS/m solution. Irrigation water at 16 dS/m was highly detrimental to growth and development of chrysanthemums. Farmers interested in the production of chrysanthemums should use irrigation water at 4 dS/m or less to prevent reduction in plant growth and development