World Crops Research Update - Okra The 2016 Growing Season Vineland is publishing Research Update Issue 4 which summarizes Vineland s findings on the okra production during the 2016 growing season. Temperatures and precipitation Okra performs well in a hot and dry environment although it is not recommended to grow okra without irrigation. Water availability during the summer became an issue for some growers as the hot and dry weather persisted and reservoirs were not replenished with rain. Under hot and dry weather conditions, a lack of water may severely limit okra s performance. Variety trial Similarly to the 2015 growing season, five okra cultivars were tested for marketable yield at the Vineland research farm. Jambalaya F1 was the highest yielding variety followed by Clemson S 80, Elisa F1 and Lucky Green F1 (see Graph 1). Picture 1: Drip irrigation system at Vineland s research farm (August 2, 2016). The 2016 growing season was hot and dry in Ontario and other parts of Eastern Canada. The average temperature in July was 23.5ºC and 24ºC in August. In Vineland, May and June were the driest months, receiving only 15.5 and 19.2 mm of precipitation, respectively. July and August received roughly half of the normal year s precipitation (48.1 and 41.4 mm, respectively). The fall was relatively warm and dry, but less dry than the spring and summer. A killing frost did not occur until November. Graph 1: Variety trial - yields. 01
The 2015 and 2016 growing seasons were both hot and dry and only minor differences in the yield potential of tested cultivars were observed. As a result of the weather conditions experienced over the last two years, the performance of okra under cooler and wetter growing conditions could not be assessed. Fumigation trial A trial was conducted on non-fumigated and fumigated lands spaced less than 50 metres apart within the same block (see Graph 2). Fumigation is necessary if soilborne pathogens such as Verticillium and Fusarium are present. On non-fumigated land, yield was reduced to a fraction of what was achieved on fumigated land. Elisa was the most susceptible variety to Fusarium and Verticillium and yield was reduced by 97.3 per cent, followed by Clemson S 80 at 96.9 per cent, Lucky Green at 95.1 per cent and Jambalaya at 94.1 per cent. It is not feasible to grow okra without fumigation on land where soilborne pathogens are present. Graph 2: Variety trial on non-fumigated vs. fumigated land. Performance under cover Graph 3 (on page 3) shows that Elisa and Lucky Green performed better under perforated plastic than floating row covers. Elisa s yield increased by 14.7 per cent under plastic and 8.6 per cent under row covers. Similary, Lucky Green s yield increased 25.2 per cent under plastic and 16.3 per cent under row covers. Picture 2: Okra under floating row covers in the spring at Vineland s research farm (June 3, 2016). 02
was applied (50 kg/ha pre-planting and an additional 25 kg/ha through drip irrigation during the growing season after plants started to bloom). Fertigation was applied from July to the end of August, once a week. Similar trends were observed in both 2015 and 2016. It is important to note that a concentration of nitrogen above 75 kg/ha, negatively impacts yield. Graph 3: Okra s performance under covers. It is important to assess the cost of installing a cover system. A 15 to 25 per cent yield increase for Lucky Green could make it worthwhile considering that covers provide an earlier harvest and possibly a premium pricing. Nitrogen rates Picture 3: Optimal nitrogen rates for highest yield (September 19, 2016). Graph 4: Okra nitrogen response curve. Five different nitrogen rates ranging from 0 to 100 kg were tested at the research farm. The highest yield was achieved when a total concentration of 75 kg/ha nitrogen Impact of row spacing on yield Similarly to the 2015 growing season, five different types of row spacing ranging from 25 cm (10 inches) to 55 cm (22 inches) were tested in double-row raised beds covered with plastic mulch. Elisa and Lucky Green performed best at a 25 cm (10 ) spacing while Clemson and Jambalaya performed best at 30 cm (12 ). According to findings, as spacing increases, yields decline. 03
After two years of experimenting with various types of row spacing, a spacing between 25 and 30 cm has shown to be optimal. Growers might use Graphs 5 and 6 as a guide to further refine spacing for the four tested varieties. New okra varieties In addition to the four varieties of okra tested, new hybrid varieties from East West Seeds Company Ltd. were also investigated. Unfortunately seeds arrived in early July when the season was well underway. Okra seeds were planted directly in black plastic mulch at the research farm. The goal was to assess growth habit, yield potential, pod size, colour and get first hand experience on growing these new varieties under Ontario s weather conditions. Bendiya and Maha did particularly well while Dorota was an average yielding variety. We believe that these varieties may perform even Picture 4: New okra varieties from East West Seeds Company Ltd. tested at Vineland s research farm (September 25, 2016). better than existing varieties currently available to growers. However, these cultivars have yet to be tested through a complete growing season. Graph 5: Impact of row spacing - Lucky Green and Elisa. Graph 6: Impact of row spacing - Clemson and Jambalaya. 04
Vineland Research and Innovation Centre 4890 Victoria Avenue North, Box 4000 Vineland Station, ON L0R 2E0 tel: 905.562.0320 @vinelandrsrch VinelandResearch vinelandresearch.com About Vineland s Feeding Diversity: Bringing World Crops to Market As part of a collaborative group of partners determined to build a local ethno-cultural vegetable marketplace, Vineland is leading research on new crop varieties (okra, Asian and Indian eggplant), production technologies, postharvest innovations, consumer insights and market development. Vineland s production team is trialing new varieties to assess agronomic performance and disease resistance, while postharvest scientists are working to optimize storage conditions to preserve the quality of ethno-cultural vegetables through the distribution chain and at retail. Picture 5: Okra flower (August 16, 2016). Takeaway messages The highest yielding variety was Jambalaya F1 followed by Clemson S 80, Elisa F1 and Lucky Green F1. Fumigation is a must when soilborne pathogens are present. Plants performed better when seedlings were planted under perforated plastic than floating row covers. The best yield response was obtained when 75 kg/ha of nitrogen was applied (50 kg/ha pre-planting, 25 kg/ha through drip). Spacing is critical to achieve high yields - 25 to 30 cm spacing in double-row raised beds is optimal for all varieties. To review other research updates, visit vinelandresearch.com and click on research programs/feeding diversity. If the information contained in these research updates is of interest to you or if you have any questions, please contact Dr. Viliam Zvalo, Research Scientist, Vegetable Production at: 905-562-0320 x808 or viliam.zvalo@vinelandresearch.com 05