Performance of Papaya Cultivars in the South of Haiti
Ludger Jean Simon1*, Clénold Raymond1, Sergio Duclona1, Pierre Duclona1, and Jean Harry Dominique2
1American University of the Caribbean
Pierre Toussaint Campus
Route Nationale No. 2, Charpentier
Les Cayes, Haiti
2Catholic Relief Services
11, Rue Toussaint Louverture
Les Cayes, Haiti
Additional index words. Papaya ringspot virus, disease index, fruit yield.
Abstract. Papaya is one of the most nutritionally and economically important fruits grown in Haiti. A field experiment was conducted at Ducis, South Haiti, to evaluate six introduced papaya cultivars (Red Lady# 786, Gold Maradol, Red Maradol, Hawaiian Solo Sunrise, Tainung#1, and Known You #1) and two local selections (CA 1208-1, CA 1310-1,) for tolerance to PRSV, plant vigor, and fruit yield. The experimental design was a randomized complete block of eight papaya cultivars in three replications. The experimental unit consisted of 5 papaya plants with a spacing of 2.5 m within and between the rows. The variables measured were stem diameter, plat height, disease index, and fruit yield. There was no significant difference for stem diameter, but there were significant differences for plant height, disease index, and fruit yield. The papaya cultivars Tainung #1, Known You # 1, and Red Lady#786 are recommended for their high yield potentials. The cultivar Gold Maradol and the local selection CA1208-1 could also be recommended for their tolerance to PRSV.
Introduction
Papaya (Carica papaya L.) is one of the most nutritionally and economically important fruits grown in Haïti. It is a rich source of antioxidant nutrients such as carotenes, vitamin C, and flavonoids (Le Bellec and Renard, 2002; Purseglove, 1991; Rice et al., 1990). Papaya is also the source of the digestive enzyme papain, which is an industrial ingredient used in brewing, meat tenderizing, pharmaceuticals, and cosmetics (Samson, 1989; Morton, 1987). In 2011, the national production was estimated to 98 MT for an area of 9 ha (FAO, 2014). As a comparison, the production in Jamaica and the Dominican Republic was respectively 5,846 and 891,731 MT in 2011 (FAO, 2014).
The papaya ringspot virus (PRSV) is the most severe papaya disease and is often the limiting factor in papaya production throughout the world (Nishina et al., 2000). The PRSV is widespread on Haiti and the important papaya production countries of the Caribbean islands. The earliest symptoms are a yellowing and vein-clearing of young leaves (Crane, 2013). A very conspicuous yellow mottling of the leaves and sometimes severe blistering and distortion can follow. Dark-green streaks and rings also appear on leaf stalks and stems. Symptoms persist on ripe fruit as dark orange-brown rings. Vigor of trees and fruit set is usually reduced depending on the age of the plant when infected. Fruit quality, particularly flavor, is adversely affected (Gonsalves, 1993; Biosecurity Queensland, 2012).
Successful commercial production of papaya in Haiti is dependent on a well-defined PRSV Management strategy. PRSV tolerant papaya cultivars have been developed from breeding programs in countries such as the United States and Taiwan. However, these materials have not yet been sufficiently evaluated in Haiti. The objective of this study was to evaluate six introduced papaya cultivars and two local selections for tolerance to PRSV, plant vigor, and fruit yield.
Materials and Methods
A field experiment was conducted during the period of February 2014 to March 2015 at the Experimental Farm of the Club l’Agriculture pour la Recherche et l’Encadrement Technique (CARET) at Ducis, South Haiti, located at 18.23590ᶿ N latitude, 73.88023ᶿ W longitude, and an altitude of 94 m above sea level. The location is classified as Af by Köppen and Geiger. The average temperature is 26.2ºC and the average annual rainfall is 2,344 mm (Climate data, 2016). The soil of the experiment site was classed as sandy clay, containing 37% clay, 13% silt, and 50 sand. The soil pH was 7.2.
The experimental design was a randomized complete block of 8 papaya cultivars (CA 1208-1, CA 1310-1, Red Lady# 786, Gold Maradol, Red Maradol, Hawaiian Solo Sunrise, Tainung#1, and Known You #1) and three replications. The experimental unit comprised one row of 5 plants, with a spacing of 2.5 m between plants within and between the rows. This translates into an area of 31.25 m2 per experimental unit.
Papaya seedlings were grown in nursery established on 18 December 2013 at the Experimental Farm of the American University of the Caribbean (AUC) at Charpentier, Les Cayes, and were transported to the field on 3 February 2014 when they were 10-12 cm in height. The fertilizer program consisted of two applications of 12-12-20 NPK fertilizer at the rate of ¼ lb per papaya plant, one month and four months after planting (MAP). Irrigation water was provided at regular intervals of 5-7 days depending on the amount and distribution of rainfall throughout the crop cycle. Weeds were controlled using garden hoes. There were no intentional control measures for pests and diseases.
Stem diameter and plant height were measured for each plant on 7 May 2014 when the papaya plants were at flowering stage. Disease index was calculated for PRSV on 31 May, 26 June, and 8 August 2014, multiplying the incidence of PRSV (number of diseased plants divided by number of observed plants) by the severity of PRSV, using a scale of 1 to 9 where 1 refers to absence of the disease and 9 plants dying or completely died (Rohrmoser, 1985). Papaya fruits were harvested, counted, and weighed on 10 Sept. 2014 – 26 Mar. 2015. Analysis of variance and Duncan Multiple Range Test were performed at 5% alpha error.
Results
There was no significant difference between treatment means for stem diameter. In contrast, there was a highly significant difference for plant height (Table 1). The local selection CA 1310-1 depicted the tallest height while Red Maradol depicted the shortest height. A taller papaya plants means more efforts to harvest the fruits which translates into increased cost of labor for the commercial grower.
There was no significant difference between treatment means for disease index at the first evaluation date, but significant differences were detected at the second and third observations (Table 2). The papaya cultivar Hawaiian Solo Sunrise depicted the highest disease index, translating into the highest susceptibility to PRSV among the varieties tested. The papaya cultivars Red Lady# 786, Tainung #1, CA 2108-1, and Gold Maradol showed the highest tolerance to PRSV at the second observation date, while the cultivars Known You #1, Red Lady #786, CA1208-1, and Gold Maradol showed the highest tolerance at the third observation date.
Significant difference was found between treatment means for both the number of fruits harvested and fruit yield expressed in kilogram per hectare (Table 3). “Tainung #1”, followed by “Hawaiian Solo Sunrise” depicted the highest number of fruits per hectare, without significant difference between the other six cultivars. The papaya cultivar Tainung #1, followed by “Known You #1” and “Red Lady# 786“depicted the highest fruit yield. There was no significant difference between the remaining cultivars. Although “Hawaiian Solo Sunrise” was among the two cultivars with the highest number of fruits per hectare, it was among the group with the lowest yield in kg/ha due to the small size of its fruits.
The results of this experiment show that papaya can be successfully produced in the Valley of Les Cayes, if cultivars that are tolerant to PRSV are adopted by the producers. The cultivars Tainung #1, Known You # 1, and Red Lady#786 are recommended for their high yield potentials. The cultivar Gold Maradol and the local selection CA1208-1 could also be recommended for their tolerance to PRSV.
Table 1. Stem diameter and plant height at flowering
| Cultivar | Stem diameter (cm) | Plant height (cm) |
| CA1208-1 | 3.14 a | 80.33 bc |
| CA1310-1 | 3.92 a | 127.50 a |
| Red Lady #786 | 3.74 a | 84.83 bc |
| Gold Maradol | 4.06 a | 106.33 ab |
| Red Maradol | 3.11 a | 64.87 c |
| Hawaian Solo Sunrise | 3.66 a | 107.93 ab |
| Tainung #1 | 4.15 a | 107.37 ab |
| Known You #1 | 3.52 a | 88.00 bc |
Table 2. Disease index
| Cultivar | 31 May 2017 | 26 June 2017 | 8 August 2017 |
| CA1208-1 | 0.47 b | 1.00 b | 2.30 b |
| CA1310-1 | 1.73 ab | 3.47 ab | 5.00 ab |
| Red Lady #786 | 0.83 ab | 1.43 b | 3.33 b |
| Gold Maradol | 0.47 b | 1.00 b | 1.80 b |
| Red Maradol | 1.20 ab | 2.27 ab | 4.50 ab |
| Hawaian Solo Sunrise | 2.80 a | 4.33 a | 7.00 a |
| Tainung #1 | 0.63 ab | 1.23 b | 4.13 ab |
| Known You #1 | 0.80 ab | 2.13 ab | 3.67 b |
Tale 3. Fruit yield
| Cultivar | No. of fruits /ha | Fruit weight (t/ha) |
| CA1208-1 | 8,746.67c | 8.82 d |
| CA1310-1 | 6,720.00 c | 9.69 d |
| Red Lady #786 | 11,413.33 c | 20.23 bc |
| Gold Maradol | 9,808.93 c | 12.92 cd |
| Red Maradol | 7,360.00 c | 7.83 d |
| Hawaiian Solo Sunrise | 20,800.00 b | 8.82 d |
| Tainung #1 | 31,253.33 a | 33.12 a |
| Known You #1 | 12,800.00 c | 22.81 b |
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