Seeds germination, nursery development and environmental conditions assessment for growing cashew nut (Anacardium occidentale L.) in Pakistan

Abstract

Cashew nut (Anacardium occidentale L.) is a multipurpose tree that is cultivated worldwide for its economic importance and nutrient values. Pakistan is one of the big consumer countries of cashew products, and spends huge amount of foreign exchange for importation. Despite the country is agricultural, there is neither cashew nut cultivation in Pakistan nor a trial for cashew nut plantation establishment. Knowing that cashew nut is ranked first crop nowadays and is a promising tree for many alternatives especially biofuel and food conservative, the objective of this study was to (1) assess the environmental conditions for growing cashew in Pakistan in order to introduce its cultivation as economical and medicinal important crop, (2) investigate the optimized conditions and parameters for cashew seed germination, (3) develop a full guideline for cashew nursery development and (4) analyze the phytochemicals (secondary metabolites) constituent of cashew young seedling leaves. To achieve these objectives, 30 seeds of cashew nut were subjected to germination in two glass house chambers with different conditions (temperature along with humidity, soil type, sowing position) set for maximum two months. The time before sprouting (TBS) of each germinated seed were recorded and collected data from germination were statistically analyzed for significance using Microsoft excel one way analysis of variance. After germination, the obtained seedlings were kept up to four months then leaves were collected from them for preliminary phytochemical, qualitative GCMS, antifungal activity against Aspergillus flavus and Candida albicans, and antioxidant potential using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging assay. Leaves were air dried, ground and plant extract was obtained via five days maceration process with methanol. The environmental conditions assessment was assayed by analyzing the available data on annual temperature and rainfall for the last two years; and optimal soil types for cashew plantation in Pakistan. While this research resulted significantly (p<0.05) that cashew nut seeds germination depends on the temperature and soil type, the position of seed for sowing seems not affecting germination of cashew nut significantly (p˃0.05). The qualitative GCMS revealed novel profile of cashew leaves with diverse compounds from the methanolic extract and major groups were Alkaloid, Phenols, Amine, Aster, Amide, Alcohol, Amino acid with an important compounds having biological, medicinal and industrial interests such as glycidol, gentamicin a, (2- Aziridinylethyl)amine, Phenylephrine, Topotecan, Cephalexin. Both antifungal and antioxidant assays showed the potential of cashew nut seedling leaves to inhibit growth of Aspergillus flavus and Candida albicans, and DPPH radicals activity respectively. The results of this work exhibit the way to get cashew nut seedlings accurately and efficiently for nursery and imply that seedlings have potential to survive in the orchard, which according to the study could be established at Punjab and Sindh regions for cashew nut cultivation exploration in Pakistan.