Cultivation trials of hop (Humulus lupulus L.) in semi-arid environments

Abstract

The recent developments in the market and craft beer industry in Italy have led to an increasing demand for local raw materials, such as barley malt and hops. Few works have been addressed to evaluate suitability and productivity of hop in semi-arid Italian environments. With this purpose, two experiments were carried out in 2018 and 2019, testing the suitability to cultivation of three commonly used hop varieties (Cascade, Chinook and Nuggett) in two typical semi-arid environments in Sicily. Phenological stages were also evaluated, and GDDs accumulated in vegetative and reproductive stages were calculated according to 9 different methods, dealing with three T base temperatures (0 °C, 5 °C and 10 °C) and with different adjustments of daily thermal sums for T max values >30 °C. The obtained hop cones were used to prepare small batches of beer (fresh hop American Pale Ale), further submitted to sensory analysis through a panel test. The results have shown a high variability of yields and biometrical characteristics of the tested hop varieties according to the cropping management. However, a definite advantage showed up for the earliest maturing variety (Chinook), that allowed cones yield of 41 g per plant (d.m.) and biomass yield of 143 g per plant (d.m.). The sensory analyses assessed the excellent organoleptic characteristics of the obtained hop, as well as of the beer produced. Hop demonstrates to be a promising crop for semi-arid Mediterranean environments, although many aspects of cropping technique are still to be pointed out.

Hops (Humulus lupulus L.) as a Novel Multipurpose Crop for the Mediterranean Region of Europe: Challenges and Opportunities of Their Cultivation

“…For this reason, studying hop phenology in new growing areas (e.g., southern European environments) can give useful directions for both selection of cultivars and temporal optimization of agronomic practices. To the best of our knowledge, just two studies, both in Italy, described the phenology of hops in the Mediterranean Basin [14,62]. Specifically, Rossini et al (2016) [14], in a three-year open field study, calculated the GDD accumulation for the onset of each of the four key growing stages (sprouting, flowering, development of cones and maturity of cones) of twenty hop cultivars in Central Italy.…”

“…Spat' were the latest ones. Marceddu et al (2020) [62], in their two-year pot experiment, showed the progress of development stages for three hop varieties in the semi-arid environment of Sicily. They calculated GDD accumulation starting from transplanting date in which plants were at the second pair of leaves unfolded (phase 1.2, according to BBCH scale, [61]).…”

“…Other varieties that performed well under different experimental conditions were 'Hall. Magnum', 'Chinook', and 'Yeoman' [14,62,63]. Understandably, the agronomic data available from open field trials in such a new growing country are very few and collected on a limited number of plants (from three to five per replicate).…”

“…Micropropagation was used in hops mainly for virus eradication [72], cryopreservation [73], and mass shoot production [74]. Very recently, trials conducted in Southern Italy evidenced that micropropagation protocol adopted for hops, although successful for many other crops, did not perfectly succeed in obtaining healthy and vigorous plants [62].…”

Agronomic and chemical evaluation of hop cultivars grown under Mediterranean conditions

“…Rossini et al (2016Rossini et al ( , 2020 also stated that in central Italy the growth and yield of hop cultivars were affected significantly by the weather conditions, particularly by reduced precipitation and high temperatures. Marceddu et al (2020) reported a high variability of hop yield according to crop management in the region of Palermo in Italy.…”