Effect of Ratooning X17-2 x T5 Papaya Plants on Crop Yield and Survival

Abstract

Selected plants in a three-year-old 0.3-acre papaya ringspot virus resistant, transgenic X17-2 x T5 (Accession 2562) papaya planting were used to: a) compare the yield from single-stemmed and multiple-stemmed plants (Trial 1) and; b) to compare the yield of plants cut at different heights (Trial 2). The original planting sustained significant damage after a brief but intense tropical storm on 19 June 2014. Some plants lost their apex and most plants had small side-shoots left intact. On 2 February 2015 (Trial 1), 15 bisexual plants were cut to 120 cm above the soil line, removing the main trunk; the main trunks of 15 other bisexual plants were left intact. On 3 March 2015 (Trial 2), 16–32 randomly selected bisexual or female plants were left intact or cut to 30 cm, 60 cm, 90 cm, or 120 cm above the soil line. Fruit production was evaluated by counting the number of fruit per plant over seven harvests and five harvests in Trial 1 and 2, respectively. In Trial 1, there was no significant difference in mean number of fruit among plants with or without the main trunk left intact. Mean fruit per plant ranged 0.3–17 fruit per plant. In Trial 2, there was no significant difference in mean number of fruit per harvest among plants cut to 60 cm, 90 cm, and 120 cm; all plants cut to 30 cm died prior to the first harvest. Mean fruit per plant ranged 0.3–16 fruit per plant.