Growth and leaf morphology of hazelnut cultivars grown under semi -controlled conditions

To be competitive, the French hazelnut growers need to evaluate new hazelnut cultivars and their adaptability to contrasting environments in terms of water and mineral resources. The ability to use resources efficiently, including water (i.e., water use efficiency, WUE) can be studied at different levels such as at foliar level. To study WUE, it is necessary to standardise the measurement of the leaf position on the stem and to work on the first mature leaf of a fully illuminated branch. The objectives of this study were (i) to assess the variability of eight hazelnut cultivars as to their leaf morphology and physiology (first mature leaf), and biomass production; (ii) to compare these varieties to one another on the tested traits; and (iii) to assess the relationships between the different traits. Eight hazelnut cultivars were conducted for two months in a cold greenhouse under semi -controlled conditions. The first mature leaf was determined and was located at the seventh leaf position after the first leaf measuring more than 20 mm below the apex. Two reference cultivars (Coraber and 'Pauetet') showed significantly larger trunk diameters and 'Coraber cultivar had noticeably more woody and foliar biomass and roots than 'Sacajawea' cultivar. This data showed the higher vigour of the 'Coraber reference. Strong correlations between physiological, and foliar morphological traits, and among biomass traits, were observed. No strong correlations were evidenced between foliar and biomass traits. This study will provide the opportunity to standardise samples for cultivar comparisons as their water -use efficiency, and help classify hazelnut cultivars.