Effect of plant architecture on the performance of high-chill pear cultivars topworked on a low-chill subtropical pear Yadav Ashish1, Yadav Anand K.2, Bist L. D.3 1Field Research Laboratory, Defence Research and Development Organization, C/O 56 APO, Leh-Ladakh, Jammu and Kashmir, India 2Agricultural Research Station, Fort Valley State University, Fort Valley, Georgia, USA 3Department of Horticulture, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India. Online published on 5 April, 2012. Abstract Cultivation of pears in subtropical regions began with the advent of low-chill pear cultivars which produced fruit with quality inferior to high-chill European/Oriental pears. Thus, the best way to produce better quality fruit of high-chill pears in subtropics would be by topworking them on to the low-chill pears. To attain this, pruned wood with spurs of high-chill Doyenne du Comice (DCP) and Victoria pear (VP) cultivars were collected in January from Horticultural Experiment and Training Center, Chaubatia, India (6825’ above MSL) and tongue grafted on low-chill Pant Pear-18 (PP-18). Both the scions were grafted at different heights on the rootstock trees using 25 and 100 cm's long stocks on Tatura trellis-trained PP-18 trees at the Horticulture Research Center, Pathar Chatta (760’ above MSL). More than 90% grafts of both DCP and VP pears succeeded and produced high quality fruits; however, DCP grafts had an edge over VP scions. Both high-chill cultivars topworked on 25 cm stocks had better graft success than the scions topworked on 100 cm stocks. The increase in topworking heights on stock trees reduced the number of floral spurs in both high-chill DCP and VP scions. Per cent fruit retention in both high-chill scions grafted on 25 cm stocks was higher than those scions grafted on 100 cm stocks. With the incremental height of top working, fruit yield in both DCP and VP scions were significantly curtailed irrespective of the stock lengths used for grafting. Fruit quality attributes assessed by organoleptic testing and TSS, total sugars, acidity and ascorbic acid contents were better for both DCP and VP than for PP-18 as well as other local subtropical pear cultivars. The reuse of previous year's scions topworked even after artificial chilling and/or GA3 treatment in order to supplement chilling exhibited no fruiting advantage over the grafting using fresh scions. Feasibility and advantages of a high quality pear production system evaluated in the subtropics are discussed relative to grower profitability. Top |