Detailed understanding on site-specific micro-environmental conditions and crop management requirements is necessary for optimal yield and grain quality of recently introduced industrial hemp (Cannabis sativa L.) varieties. Genetic factors, along with environmental drivers such as growing season, temperature, day length, soil nutritional status, and other stress conditions, significantly affect the growth characteristics and flowering events of industrial hemp, making the biomass yields and grain quality site-specific. In order to fill the information gap specifically under local cropping systems, we evaluated the growth performances of recently introduced industrial hemp varieties grown in Tullakool, NSW (irrigated) and Creswick, VIC (rainfed). Ten varieties originated from Poland (Bialobreszkie, Henola), France (Fedora-17, Orion-33, Fibror-79), China (Han NE), Canada (Anka, CRS-1) and Australia (Frog-1, MS-77) were evaluated for, sex expression, average plant height, average stem diameter, number of inflorescences/plant, stem yield/ha and seed yield/ha, thousand grain weight and harvest index. A Pearson correlation analysis was conducted separately for biomass and dual-purpose varieties to determine the relationships among measured plant traits and yields.
Results of these trials demonstrated a wide variation of field performance with respect to the growing environment and the in-crop management practices. Among the varieties tested, highest stem dry matter yields were recorded by Frog-1 (7.4 MT/ha) in Tullakool and MS-77 (5.08 MT/ha) in Creswick. Highest seed yields were produced by Han NE (2.24 MT/ha) in Tullakool and in Creswick, it was Henola (0.99 MT/ha). Both MS-77 and Frog-1 varieties showed promising characteristics for biomass production in both respective locations. The allometric and yield performance of the Frog-1 variety grown in both sites were highly contrasting. Han NE variety in Tullakool site showed a relatively greater potential as a dual-purpose crop, as this variety produced relatively longer average stems (2.08 m) and superior average stem diameter (9.4 mm), along with good stem yield (4.7 MT/ha) and grain yields (2.3 MT/ha), compared to other dual-purpose varieties assessed. Preliminary results suggest that all the varieties can successfully be cultivated during summer months in Southeast Australia. However, ongoing studies also emphasize the need for adopting site-specific agronomic practices to ensure the best outcomes in terms of desired end products (fibre/grain) under Southeast Australian environmental conditions.