Effect of Seed Treatment, Nursery Potting Media and Watering Frequency on Emergence and Seedling Growth of Korarima (Aframomum cororima (Braun) P.C.M. Jansen)

Abstract

Korarima (Aframomum corrorima) is native crop to Ethiopia, tropical herbaceous, perennial and aromatic spice and medicinal crop widely used in traditional dishes, and sold at higher prices. Despite its importance, genetic variability and favorable ecology, production of the crop is much lower mainly due to production constraints such as :Lack of improved variety, Poor agronomic practices , Inappropriate propagation techniques and Shortage of planting material for production . Korarima can be propagated by seed and vegetative parts. The seed propagation method need for bulk as planting materials and not susceptible to unknown diseases is one of these major qualities. On the other hand, germination of seeds has problem of seed dormancy, which may be associated with the hard and impermeable seed coat. Seed treatment to break dormancy and good nursery media composition and optimum watering frequency for improved seed emergence and seedling growth constraints have not been well studied and documented. Thus, the current study was conducted with the objective of determining the effect of different seed treatment methods, media composition and watering frequency on seed emergence and subsequent seedling growth. Two experiments were carried out. Experiment I has two factors. Seed treatment at five levels((0 hrs,24 hrs , 48 hrs , 72 hrs) water soaking, & 50% sulfuric acid soaking for 60 minutes) &Soil media of seven levels (Forest, Top , Forest : Top , Forest : compost , Top : compost , Forest : Top soil : compost, Top : compost ( 3:1) ), & laid out in 7x5 factorial arrangement using RCBD with three replications. Experiment II has two factors. Soil media seven levels as indicated in experiment I and Watering frequency days four levels (every day , two , three & four) was conducted using split plot design with three replications.The data recorded on korarima seed emergence and early seedling growth were subjected to Analysis of Variance using statistical analysis system version 9.2 software. Treatment means were separated using LSD at 0.05 probability level. The interaction effect of seed treatment by soil media and watering frequency by soil media were highly significant (p<0.01) for mean days to emergence, emergence % and seedling growth parameters. The highest score of mean days (14) & emergency percentage (90) and seedling growth parameters were obtained under seeds soaked for 24hrs followed by 48 hrs in pure water and sown on media of forest soil, top soil & compost in (3:1), forest & top (1:1) and top & compost (1:1). Other treatments shown low emergence % Korarima seeds sown in mixed forest and top soil and also top soil and compost soil media combination in equal ratio with watering frequency every days gave days (15) or shown early emergence and (85.63) emergence percentage. Watering frequency every four days shown late emergence days. The correlation among some growth parameters and relative growth rate were also highly significant (p<0.01). In general, all treatments showed highly significant (p<0.01) variation in terms of shoot height, root length, stem girth seedling vigor index, leaf area ,leaf number, total dry weight, root volume, relative growth rate. It can be concluded that pre-sowing seed water treatment 24,48 hrs , Watering frequency every one or two days and media of top soil and compost combinations improved both seed emergence and growth of seedlings. it would be advisable for nursery operators to irrigate korarima seedlings every two days or three days interval with compost soil combination under the prevailing conditions.