Skip to main content
ARS Home » Pacific West Area » Corvallis, Oregon » National Clonal Germplasm Repository » Research » Publications at this Location » Publication #191625
Title: IRON FORMULATION AFFECTS IN VITRO STORAGE OF HOPS: AN IMAGE ANALYSIS

Author
item AYNALEM, HAILU - OREGON STATE UNIVERSITY
item RIGHETTI, TIMOTHY - OREGON STATE UNIVERSITY
item Reed, Barbara

Submitted to: In Vitro Cellular and Developmental Biology - Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2006
Publication Date: 1/20/2006
Citation: Aynalem, H., Righetti, T., Reed, B.M. 2006. Iron formulation affects in vitro storage of hops: an image analysis. In Vitro Cellular and Developmental Biology - Plants. 42:405-410.

Interpretive Summary: The US Department of Agriculture, Agricultural Research Service,National Clonal Germplasm Repository, Corvallis (NCGR) stores the US collection of wild and cultivated hops. Hops are usually stored as trellised plants in field collections. These plants are susceptible to loss from environmental stresses and insect or disease attacks. To insure the safety of the collection, a subset of the field collection was established as virus-free tissue cultures stored at refrigerator temperatures. Storage of cultures at refrigerator temperatures averages 14 months, but can vary from 6 months to 2 years depending on the plant type stored. In this study we tested 8 hops cultivars to determine the effect of the iron formulation in the growth medium on the length of storage. All of the plants grown on the standard formulation (EDTA-chelated iron) were healthier after 9 months than either of the two treatments with a different formulation (EDDTA-chelated iron).

Technical Abstract: In vitro-stored plant germplasm at genebanks, such as the US Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repostiory, Corvallis is usually evaluated by visual analysis of the plant based on subjective characters. To reduce the variability in these evaluations, we developed a digital-image evaluation system for in vitro-stored plantlets. This study compares the standard visual evaluation system with a digital analysis system to determine if digital analysis can effectively quantify the health of diverse Humulus germplasm. Eight Humulus lupulus L genotypes were stored on standard MS iron alone (EDTA chelated) and on MS iron with 100 or 200 mg L-1 sequestrene 138 iron (EDDHA chelated). Digital images of the upper two nodes of each plantlet were evaluated for red, green, blue, green/red ratio, and modified normalized difference vegetation index (MNDVI=R-G/R+G). Evaluation of each plantlet for MNDVI values showed consistent significant differences for all treatments only at the upper node. Significant differences for visual and the MNDVI values among the three iron treatments were observed at the upper node of most of the eight hop cultivars. Regression analysis of the upper node MNDVI values vs. whole-plant visual ratings showed positive correlations for most cultivars. Effects of iron treatments on storage duration were also analyzed for both visual and digital systems. There were significant differences among MNDVI values for plantlets stored on medium with standard MS iron alone (EDTA chelated) and with the addition of sequestrene 138 iron. In general the MNDVI value of the upper node correlated well with visual ratings and could be used to determine the health of in vitro stored hops.