World Crops Research Update - Eggplant The 2017 Growing Season This Research Update summarizes Vineland s findings on Asian eggplant production for the 2017 growing season. Temperatures and precipitation This summer in Vineland, ON was cool and wet compared to 2016. Cumulative Growing Degree Days (GDD, base 10ºC) from the time of planting until final harvest for 2017 and 2016 were 1,209 and 1,526 GDD, respectively (see Graph 1). Total precipitation for the 2017 and 2016 growing seasons were 280.4 mm and 177.6 mm, respectively. Picture 1: Flooding and hail damage to eggplant trials (June 27, 2017). on raised beds covered with black plastic mulch with drip irrigation tape June 3. The cool and wet weather conditions delayed planting by one week compared to 2016. A large hail storm hit the Niagara, ON region June 26 and led to widespread flooding and crop damage (see Picture 1). These conditions delayed harvest by three weeks compared to 2016. Graph 1: Cumulative Growing Degree Days (GDD) comparing 2016 and 2017 growing seasons. Production trials in 2017 Vineland s Asian eggplant trials were planted Four eggplant cultivars were evaluated for total marketable yield on four different rootstocks. Asia Beauty, Chu-Chu, Long Purple and Orient Express were grafted onto Kaiser, Maxifort, DR0141TX and DR0131TX between April 6 and April 12. 01
Grafted and non-grafted controls were planted June 3 on raised beds with black pastic mulch in double rows spaced 30 cm apart with in-row spacing of 46 cm. The raised beds were prepared with a centre-to-centre distance of 180 cm (see Picture 3). No additional fertility trials were conducted in 2017 since data from the 2015 and 2016 growing seasons and published literature provided us with sufficient information to optimize growing conditions. A concentration of 125 to 150 kg of nitrogen per hectare is recommended to produce the highest marketable yield of eggplant. Half of the needed concentration of nitrogen and potassium was applied in the spring before beds were formed. The rest was applied in the form of potassium nitrate through a drip irrigation system at a rate of 7.5 kg/ha per week. Four new cultivars (Femi, Ziyi, Jin and Raveena) from East-West Seeds Ltd. were tested alongside the grafting trials although these Picture 3: Eggplant trial layout at Vineland s Research Farm (August 17, 2017). were tested on their own roots due to the late arrival of seeds. Femi and Ziyi are similar to Asia Beauty and Long Purple, while Jin is similar to Orient Express but with a green calyx. Raveena is a variegated specialty cultivar of long Chinese eggplant. Non-grafted Femi, Jin, Raveena and Ziyi were transplanted using similar specifications as used in the grafting trials (see Picture 2). Picture 2: Eggplant cultivars tested at Vineland s Research Farm (August 17, 2017). 02
and Asia Beauty. The rest of the cultivars were producing marketable fruit by August 8. Cultivar trial results Among the Asian long eggplant with light purple skin, Ziyi produced the highest marketable yield followed by Femi and Asia Beauty (see Graph 2). Long Purple had the lowest marketable yield. This variety has been a staple of Chinese long eggplant production due to its appearance and quality, although in terms of production it is one of the lowest yielding. Graph 2: Total yield of Asian long eggplant with lighter skin. The non-grafted controls for each cultivar were the first to have marketable fruit. Similarly to 2015 and 2016, grafting delayed flowering and first harvest by one to two weeks. In general, grafted plants were healthier and produced higher yields for the remainder of the growing season. The final eggplant harvest occurred October 5. Ziyi yielded 40 t/ha compared to Long Purple at 22 t/ha, an increase of 45 per cent. Both Femi and Ziyi could be viable replacements for Long Purple provided that East-West Seeds markets these varieties in North America. Since East-West Seeds works with local seed companies, it is anticipated these varieties will be available in North American vegetable seed markets. It is important to have a regular harvest schedule for Asian eggplant as the fruit can quickly become overgrown and unmarketable. To meet retailers specifications, Asian long eggplant must be harvested with a diameter of 4.4 cm to 5.7 cm and a length of 23 cm to 35.5 cm. For Indian round eggplant the diameter must be 4.4 cm to 5.7 cm. Harvest in 2017 Eggplant at Vineland was harvested twice weekly, with the first harvest occurring July 18. Orient Express was the first cultivar to reach production, followed by Long Purple Graph 3: Total yield of Asian long eggplant with darker skin compared to the specialty-cultivar Raveena. 03
Among the Asian long eggplant with dark purple skin, Orient Express produced the highest marketable yield at 36 t/ha, while the dark-skinned eggplant Jin produced nearly a 21 per cent lower yield (see Graph 3, Page 3). Orient Express has been the best performing long eggplant variety over the past three years. It will be difficult to find a replacement for such a solid performer in both field and greenhouse settings. Grafting trial results Grafting onto disease-tolerant rootstock is an effective strategy to overcome soilborne pathogens. Grafting trials started in 2015 when plants were grafted onto Maxifort rootstock, then in 2016 Long Purple scions were grafted onto four different rootstocks and assessed for field performance. In 2017, the project was further expanded to test four eggplant cultivars (Asia Beauty, Chu Chu, Long Purple and Orient Express) onto four different rootstocks (DR0138TX, DR0141TX, Kaiser and Maxifort) to determine field performance. In 2016, grafted plants performed better than their non-grafted controls. Under the cooler and wetter growing conditions of 2017, non-grafted plants generally produced a higher marketable yield than grafted plants (see Graph 5). Graph 4: Total yield of all eggplant tested in 2017. Chu Chu was the only Indian round eggplant tested and produced the highest yield out of all cultivars grown in the field (see Graph 4). Initially, a number of round varieties were tested and none came close to matching the performance of Chu Chu. For field production, this is the best variety of round eggplant. During the hot summer months, this variety may lose its dark purple colour. To avoid colour fading, it is worthwhile increasing iron levels in the fertigation solution. Graph 5: Grafted Asian long eggplant performance in fumigated land. 04
Aphids, Colorado potato beetles (see Picture 4) and Japanese beetles were observed on crops and Exirel TM (DuPont Canada) was applied for control. Diseases such as Fusarium, early blight and powdery mildew are more common in wet and cold years. A regular scouting program should be used throughout summer months to detect and identify pests quickly to avoid economic loss. Graph 6: Grafted Long Purple performance on fumigated land compared to the non-grafted control. The only exception was Long Purple, which produced the greatest yield on DR0141TX at 29.6 t/ha and Maxifort at 29.5 t/ha compared to 22.1 t/ha obtained from the non-grafted control (see Graph 6). This represents an increase of more than 33 per cent increase over the non-grafted control. According to the data it appears that when grafting Long Purple eggplant, Maxifort and DRO141TX are the best rootstocks for highest crop performance. It is important to examine both the upper and under sides of leaves when looking for common pests such as aphids, thrips, leafhoppers and spider mites. For additional information on pest management, please consult the Ontario Ministry of Agriculture, Food and Rural Affairs Publication 838, Vegetable Crop Protection Guide 2014-2015. The Indian round eggplant Chu Chu has the greatest marketable yield when plants are non-grafted. This variety also performs well when minimally pruned. Even in a greenhouse environment, this variety did not perform better when grafted onto disease-tolerant tomato rootstock unlike Asian long eggplant which showed a significant yield increase. Pest management As 2017 was a cool and wet season, pest pressure was lower than in 2016. Picture 4: Colorado potato beetle on an eggplant leaf (June 6, 2017). 05
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: Harvested eggplant (September 17, 2017). Takeaway messages The cooler season and hail damage in 2017 delayed initial harvest by three weeks compared to 2016 The Indian round eggplant Chu Chu outperformed the other eggplant varieties tested in 2017 The new Femi and Ziyi cultivars have the potential to replace light purple long eggplant such as Asia Beauty and Long Purple Orient Express again outperformed the other dark purple long eggplant cultivars When Long Purple eggplant was grafted onto Maxifort or DRO141TX rootstock the yield was 33.6 per cent higher compared to the non-grafted control. To review other research updates, visit vinelandresearch.com and click on research programs/feeding diversity. If the information contained in this research update is of interest to you or if you have questions, please contact Viliam Zvalo, PhD, Research Scientist, Vegetable Production at: 905-562-0320 x808 or viliam.zvalo@vinelandresearch.com 06