CARIBBEAN FOOD CROPS SOCIETY

Transcription

1 CARIBBEAN FOOD CROPS SOCIETY 50 Fiftieth Annual Meeting 2014 St. Thomas, United States Virgin Islands Volume L

2 PROCEEDINGS OF THE 50 TH ANNUAL MEETING Caribbean Food Crops Society 50 TH Annual Meeting July 7 July 11, 2014 Sugar Bay Resort and Spa Hotel St. Thomas, United States Virgin Islands Edited by Thomas W. Zimmmerman, Stafford M.A. Crossman, Errol Chichester and Wilfredo Colón Published by the Caribbean Food Crops Society i

3 Caribbean Food Crops Society ISSN Copies of this publication may be obtained from: CFCS Treasurer Agricultural Experiment Station Jardín Botánico Sur 1193 Calle Guayacán San Juan, Puerto Rico Mention of company and trade names does not imply endorsement by the Caribbean Food Crops Society. The Caribbean Food Crops Society is not responsible for statements and opinions advanced in its meeting or printed in its proceedings; they represent the views of the individuals to whom they are credited and are not binding on the Society as a whole. ii

4 Proceedings of the Caribbean Food Crops Society. 50: INFLUENCE OF EXTENDED REFRIGERATION ON PEA SEED VIABILITY Shamali Dennery, Thomas Geiger and Thomas W. Zimmerman, University of the Virgin Islands Agricultural Experiment Station, RR#1 Box 10,000, Kingshill, VI Abstract: Peas are a commercially grown vegetable that is nutritious in providing the human body with various minerals, vitamins and anti-oxidants. The purpose of this study was to evaluate the influence of refrigerated storage on snap peas (Pisum savitum) and snow peas (Pisum macrocarpon) seed viability after four years. A germination viability test was conducted using six varieties which were replicated in petri-dishes with each treatment containing 50 seeds. Results indicated that the four year of refrigeration significantly reduced the seed viability of the snap pea varieties Super Sugar Snap (23%), Sugar Sprint (35%), and Cascadia (24%). There was no change in the germination rate for the snow pea varieties Little Sweetie and Oregon Giant. The Mammoth Melting Sugar snow pea variety had an increased rate of germination by 15% indicating a possible after-ripening. Refrigerating seed for four years can be used to maintain seed viability for the selected snow peas varieties but not for the selected snap peas. This research was supported by USDA-Hatch and USDA-NIFA-Insular Tropical Grant funds. INTRODUCTION Germination is the process by which a dormant seed begins to sprout and grow into a seedling. Epigeal (Epigeous) germination implies that the cotyledons are pushed above ground by the hypocotyl. The hypocotyl grows, while the epicotyl stays the same length. However in hypogeal (hypogeous) germination, the hypocotyl remains short, the cotyledons forces the radicle and epicotyl axis to extend out of the seed coat. The epicotyl and the seed with the enclosed cotyledons remains underground. The purpose of this study was to evaluate the influence of refrigerated storage on snap peas (Pisum savitum) and snow peas (Pisum macrocarpon) seed viability in vitro and in situ after four years. MATERIALS AND METHODS Seed viability was evaluated through germination conducted on six varieties of Pea seeds obtained from Twilley, Stokes, and Whillhite seed companies in 2010 and stored in a refrigerator for four years. Two types of peas was used :snap pea varieties Super Sugar Snap, Sugar Sprint, and Cascadia". Snow pea varieties consisted of Little Sweetie and Oregon Giant, and Mammoth Melting Sugar. In vitro germination involved selecting 50 seeds and placing them in a petri plate that contained a piece of wetted paper towel. Each variety was replicated twice. Water was applied as needed and the seeds observed daily for five days. Germination was counted and recorded when the radicle emerged from the seed. After the in vitro lab test, seeds were planted in the field with four replications in a randomized block design. Seeds were inoculated with rhizobium bacteria to encourage nitrogen fixation prior to planting. Seeds were planted at 7.5 cm spacing on both sides of the irrigation line. Germination was counted eight 187

5 days after planting when the epicotyl emerged. Χ 2 analysis was used to compare in vitro and in situ germination with the published rate from RESULTS AND DISCUSSION In Vitro germination tests indicated that the four year refrigeration significantly reduced the seed viability of the snap pea varieties Super Sugar Snap, Sugar Sprint and Cascadia (Figure 1). There were no significant changes in the germination rate for Oregon Giant and Little Sweetie. Mammoth Melting Sugar a snow pea variety had a significant increased germination rate of 15% indicating a possible after-ripening. In Situ germination, resulted in a significant decrease in germination for Super Sugar Snap and Cascadia (Figure 2). A significant increase was again evident in the Mammoth Melting Sugar seed s viability. Fig. 1. X 2 analysis of in vitro pea germination compared to original expected germination four year old seed from Fig. 2. X 2 analysis of in situ pea germination compared to original expected germination four year old seed from

6 CONCLUSION Refrigerating seed for four years can be used to maintain seed viability for the selected snow peas varieties but not for the selected snap peas. In vitro germination is not always identical to in situ germination which has less environmental control. 189