Plant covering and soil microbes application to improve grafting success of cashew (Anacardium occidentale L.) in the field

Cashew plantations generate foreign exchange and provide employment for farmers. However, cashew productivity in Indonesia is very low, due to the use of improper plant materials. The use of superior cultivars as scion grafted onto 6-month-old seedling as rootstock is an alternative to rejuvenate damaged crops and increase its productivity. The seedlings for rootstock were raised through direct seeding. The experiment was conducted from June 2015 to June 2016 at Cikampek Research Installation of Indonesian Spice and Medicinal Crop Research Institute (ISMCRI) in Cikampek District, West Java, Indonesia (50 m a.s.l., 107°27'20.99”E longitude and 6°25'10.99”S latitude). The research aimed to study the use of suitable soil microbes producing auxin and appropriate cover material to accelerate graft union formation and enhance survival rate. The experiment was arranged in a randomized block design, with two factors and three replications. The first factor was two types of plant cover (leaf sheath of pseudostem banana; leaf sheath of pseudostem banana + clear plastic bag). The second one was types of soil microbes (control, azotobacter, azospirillum, and mycorrhiza). Parameters observed were percentage of grafting survival rate, shoot length, leaves number, field determination of compatibility constant (FCC) and chlorophyll content. The use of leaf sheath of pseudostem banana + clear plastic bag as plant cover and azospirillum application indicated better percentage grafting survival rate and growth than other treatments.