Use of Trichoderma spp and saline stress in the production of watermelon seedlings

Abstract

The use of fungi of the genus Trichoderma is highly relevant for agriculture due to vegetative, root growth, increase in chlorophyll and leaf area with increasing productivity. The watermelon, a highly important fruit in Brazilian trade, is grown in semiarid areas featuring irregular rainfall and lack of good quality water. Saline water is used for irrigation, which is a limiting factor for the production of several olericulture products. Current research evaluates the influence of Trichoderma spp. in the development of watermelon seedlings irrigated with saline water. Experiment was conducted at the Universidade Federal de Campina Grande, at the Center for Sciences and Agriculture-Food Technology, Pombal PB Brazil, in a vegetable house. Treatments were distributed in a randomized block design, with factorial scheme 4 x 2 x 5, four cultivars of watermelon (Crimson sweet, Crimson Select Plus, Fair Fax and Charleston gray), two species of Trichoderma (T. harzianum and T. longibrachiatum) and five saline concentrations (0.3; 1.3; 2.3; 3.3; 4.3 dSm-1) with 4 replications. Analyzed variables comprised phenology, photosynthetic hues, total fresh and dry mass and saline tolerance index. Saline water higher than 0.3 dS m-1 reduced growth and biomass of watermelon seedlings in all cultivars. However, T. longibrachiatum coped better to the deleterious effect of saline stress when compared to T. harzianum in cultivars Fair Fax and Crimson Sweet, when tolerance and salinity index are taken into account.