COMPLEMENTED EFFECT OF GLYCINE BETAINEA AND BIOFERTILIZERS ON GROWTH AND PRODUTIVITY OF SWEET PEPPER (Capsicum annuum L.) PLANT UNDER HIGH TEMPERATURE CONDITION.

Abstract

Temperature is one of the major factors are being controlling and/or limiting growth and development of plants. The effect of plant growth promoting rhizobacteria (PGPR) (mixture of Azospirillum lipoferum, Paenibacillus polymyxa and Bacillus circulans), mycorrhizae (AM) and foliar application with glycine betaine (GB) at 0, 10 &15mmol/L individually or in combination on some growth aspects, photosynthetic pigments, microbial activities, minerals and some bioconstituents, endogenous phytohormones, flowering, fruiting and fruit quality of sweet pepper cv. California wander was studies during 2011 and 2012 seasons under open field at high temperature condition. Results indicated that, different applied treatments significantly increased most growth parameters as number of branches and leaves per plant, leaf area per plant, leaves and shoot dry weight per plant and leaf area ratio as well. Furthermore, photosynthetic pigments, NPK, total sugars and total free amino acids concentration in leaves recoded the maximum values when plants treated with PGPR, AM and foliar application with GB at 10 mmol/L as compared with those of individual application or untreated ones. Moreover, individual application with PGPR, AM and / or GB at 10 mmol/L enhanced the microbial activities in rhizosphere of the pepper plants compared with untreated ones. Also, biofertilizers and GB treatments increased auxin, gibberellin and cytokinin levels in sweet pepper shoots at 65 days after transplanting during 2012 season whereas abscisic acid was decreased. Moreover, the highest early and total yield were obtained when plants were sprayed with GB at 10 mmol/L and treated with microbial consortium (PGPR & AM). In addition, chemical composition of minerals and some bioconstituents such as total carbohydrates, vitamin C, total soluble solids in sweet pepper fruits were also increased at the same treatments. Hence, it could be recommended that foliar application with GB at 10 mmol/L in the presence of PGPR and AM as biofertilizers can be used to increase yield and fruit quality of sweet pepper plant when grown at high temperature condition.