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ARS Home » Pacific West Area » Corvallis, Oregon » National Clonal Germplasm Repository » Research » Publications at this Location » Publication #191227
Title: NONDESTRUCTIVE EVALUATION OF IN VITRO-STORED PLANTS: A COMPARISON OF VISUAL AND 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: 8/9/2006
Publication Date: 8/19/2006
Citation: Aynalem, H.M., Righetti, T.L., Reed, B.M. 2006. Nondestructive evaluation of in vitro-stored plants: a comparison of visual and image analysis. In Vitro Cellular and Developmental Biology - Plants. 42:562-567.

Interpretive Summary: The USDA-ARS National Clonal Germplasm Repository (NCGR) stores national collections of fruit, nut and specialty crops. The primary collections are maintained as growing plants fields or greenhouses. These plants could be lost from environmental stresses and insect or diseases. As a secondary back up a subset of the field collection was established as virus-free tissue cultures stored at refrigerator temperatures. Survival of these cultures in storage at refrigerator temperatures can vary from 6 months to 5 years depending on the plant type. Stored plants are evaluated at 4 month intervals to determine their health status. In this study we tested four cultivated pears to determine if computer analysis of digital photographs would be more effective for determining health status than a visual evaluation. Correlations between digital and visual analysis were significant for some factors. While these tests do not provide a definitive evaluation technique, they will assist in the development of digital imaging as an alternative technique for evaluation of stored tissue culture plantlets.

Technical Abstract: In vitro plants in slow-growth storage require routine evaluation for assessment of viability and timing of repropagation. Determination of plantlet health by visual assessment is subjective and varies by genus due to variations in growth pattern and plant structure. Developing a standardized system of plant evaluation would improve the efficiency of in vitro storage. This study was initiated to develop digital-image analysis techniques for plantlets during slow-growth cold storage and to compare that system with visual examinations. Pear (Pyrus communis L.) cultivars were chosen for this initial trial because they have an open structure and clear position of internodes for image composition. Pear shoots stored at 4°C in tissue culture bags were evaluated monthly by standard visual examination and by digital-image analysis. Digital images were evaluated for red, green, blue, modified normalized differences of vegetation index (MNDVI), Green/Red ratio, intensity, hue, and saturation at the first two nodes of each plantlet. At 6 mo. the visual ratings had declined steadily for P. communis ‘Luscious’ and ‘Bartlett-Swiss’ while ‘Belle Lucrative’ and ‘Louise Bonne de Jersey’ ratings did not show significant declines until 9 mo. Correlations between visual ratings and G/R and MNDVI values were significant (R2 greater than or equal to 0.5) for all cultivars. Regression analysis indicated that the MNDVI and G/R ratios changed significantly over the 15 mo. rating period for most cultivars. Intensity, hue and saturation values were not consistently significant and did not correlate with visual ratings. These results will assist in the development of digital imaging as an alternative technique for evaluation of stored tissue culture plantlets.