Effect of salinity and drought on growth performance of Guava (Psidium guajava L.)

Soil salinity and drought are mainly restrictive factors that reduce yield of crops in arid and semiarid regions of the world. Psidium guajava L. is an important fruit crop for human consumption. Guava fruit has high nutritional value and is also used for medicinal purpose. After mango, citrus and apple, guava is the fourth most important fruit in Pakistan. In order to assess the effect of salinity and drought on guava a pot culture experiment was conducted in the wire house of ISES. There were eight treatments of salinity and drought. (Control, 100 mM NaCl, 200 mM NaCl, 400 mM NaCI, Control + Water stress, 100 mM NaCI + Water stress, 200 mM NaCI + Water stress, 400 mM NaCI + Water stress). At salinity and drought level of 400 mM NaCI and 400 mM NaCI + Water stress plants did not survive. The duration of the experiment was one year. The data regarding physical growth parameters like plant height, stem diameter, number of leaves, number of branches and photosynthetic parameters was recorded. At harvest plants were separated in to roots, stem and leaves. Na+ and K+ concentration in root, stem and leaves were determined after wet digestion. The maximum decreased in plant height, stem diameter, no. of leaves per plant and no. of branches were 60, 57, 64 and 64 recorded respectively at salinity level of 20 dS/m+ water stress. Shoot fresh weight; shoot dry weight, root fresh weight and root dry weight was 67, 71, 68 and 80 % respectively. The maximum Na+ contents were 0.16, 0.49 and 3.02 mmol/g dw in root, stem and leaves respectively. The maximum decreased in K+ contents was 0.13, 0.19 and 0.50 mmol/g dw in root, stem and leaves respectively. Photosynthetic rate, transpiration rate and stomatal conductance was decreased 68, 60 and 93 % respectively, at salinity and water stress level of 20 dS/m + water stress. The data were analyzed statistically. It was concluded that Psidium guajava L. can tolerate salinity up to 200 mM NaCI with limited water supply.