Search

The virome of babaco (Vasconcellea x heilbornii) —a non-traditional fruit crop native to Ecuador— was investigated by high-throughput sequencing (HTS) on plants obtained from a commercial nursery. Six virus-like sequences were detected, including the full length of papaya ringspot virus (PRSV) and an RNA-dependent-RNA-polymerase (RdRp) sequence with homology to papaya virus Q. Three RNA sequences were found with homology, respectively, to apple latent spherical virus (genus Cheravirus, 71% nt identity), cherry leaf roll virus (genus Nepovirus, 54% nt identity) and Citrullus lanatus cryptic virus (genus Deltapartitivirus, 66% nt identity); whereas a DNA pararetrovirus-like sequence with homology to citrus endogenous pararetrovirus (58% nt identity) was also detected. RT-PCR-based virus surveys on a total of 284 samples collected from three provinces revealed that the partitivirus- and pararetrovirus-like sequences were present in 100% of tested plants; whereas the other virus sequences were detected in up to 68% of plants and were associated with different symptoms. This work provides information on the occurrence and prevalence of PRSV and five additional virus-like sequences in babaco, a vegetatively propagated crop, supporting the need for a virus-free certification program.

espanolEste articulo analiza el efecto del 1-Meticlciclpropeno en la inhibicion de etileno en el fruto de babaco (Vasconcellea x heilbornii var. Pentagona) en tres estados de madurez del fruto y tres tiempos de exposicion. Se empleo un Diseno Completamente al Azar (DCA) con cuatro repeticiones. Las variables bajo estudio fueron: la perdida de peso, la frmeza, la concentracion total de solidos solubles y el porcentaje de acidez titulable. La menor perdida de peso se registro para frutos cosechados de forma temprana (color “Verde”) y expuestos al 1-Meticlciclpropeno por un periodo corto (7 dias). En el caso de la variable frmeza de fruto, los mejores resultados se obtuvieron al cosechar los frutos cuando estos se cosechan en estado “Verde”. La concentracion de solidos solubles fue mayor para los frutos cosechados en estado “Verde-Amarillo” y “Amarillo”, mientras que los valores de porcentaje de acidez titulable se incrementan con la madurez del fruto. El tiempo de inmersion no tuvo efectos signifcativos para las variables frmeza de fruto, concentracion de solidos solubles y porcentaje acidez titulable. EnglishThis article analyzes the effect of 1-Meticlclclpropen on the inhibition of ethylene in babaco fruit (Vasconcellea x heilbornii var. Pentagona), with three ripe stages and three exposition times. A Complete Random Design with four repetitions was used. The variables under study were: loss of weight, fruit firmness, total concentration of soluble solids and percentage of titrated acidity. The lowest loss of weight was obtained for fruits harvested earlier (“Green”) and exposed to 1-Meticlciclpropen for a short period of time (7 days). In the case of fruit firmness, the best results were obtained when fruits were harvested “Green”. The total concentration of soluble solids was higher for fruits harvested in stages “Green-Yellow” and “Yellow”, while the values of titrated acidity increased with the fruit ripeness. The time of exposure to 1-Meticlclclpropen had no significant effect on fruit firmness, total concentration of soluble solids and percentage of titrated acidity.

La presente investigación se realizó con el objetivo de desarrollar un protocolo para el establecimiento y ensayos preliminares de propagación in vitro de babaco (V. x heilbornii) proveniente del distrito de Luya, región Amazonas. Se recolectaron secciones vegetativas de plantas de V. x heilbornii, evaluando desinfectantes como lejía comercial y cloruro de mercurio para el establecimiento de yemas axilares, posteriormente se evaluó diferentes concentraciones de reguladores de crecimiento auxinas, giberelinas y citocininas en la propagación in vitro de V. x heilbornii. Los resultados mostraron que el empleo de una combinación de lejía comercial al 10% más cloruro de mercurio 0,1% fueron los adecuados para la asepsia de las secciones vegetativas de V. x heilbornii. En tanto, el empleo de AIA 0,5 mg/L más 2iP 1- 2 mg/L permitieron el crecimiento y desarrollo de yemas axilares, resultados que permitirán la propagación in vitro de esta especie silvestre de importancia económica.

Southern Ecuador is generally acknowledged to be located in a biodiversity hot spot. Several species of agricultural and horticultural crops can be found there with a huge genetic diversity and can be found in wild or in semi-cultivated status as backyard crops. Cherimoya (Annona cherimola Mill.) and several species of highland papayas (Vasconcella spp.) have their centre of origin in southern Ecuador and are cultivated as minor fruit crops in several subtropical zones worldwide. Little research work has been carried out so far in exploring the crops’ centre of origin. Germplasm collection and characterisation can give valuable information to local and international crop breeding programmes whereas a detailed study of the ecology of wild stands, may provide useful information on climate and soil preferences of the crop and can -combined with a GIS analysesbe used to locate suitable cropping areas. Collection and characterisation of 137 wild and semi-cultivated cherimoya accessions was carried out in southern Ecuador between January 1996 and March 1998. A tremendous variability of pomological characteristics was encountered, typical situation of a main centre of biodiversity. The best accessions collected during these trips can easily withstand preliminary comparison with commercial cherimoya cultivars (‘Fino de Jete’, ‘Bays’, ‘White’, ‘Bronceada’ and ‘Concha Lisa’). The collection of Vasconcella germplasm was carried out between August 1997 and April 2000. A total of 211 accessions of the common species Vasconcella cundinamarcensis (Solms-Laub.) Badillo, V. stipulata (Badillo) Badillo and V. × heilbornii (Badillo) Badillo were collected together with some accessions of the rarer species V. candicans (A. Gray) A.DC., V. microcarpa (Jacq.) A.DC., V. monoica (Desf.) A.DC., V. palandensis (Badillo et al.) Badillo, V. parviflora A.DC. and V. weberbaueri (Harms) Badillo. These accessions showed great variability and raised several questions about their exact taxonomic position. Preliminary studies of the papain content of some of these accessions showed papain activities up to 20 times higher than those of papaya (Carica papaya L.). Edapho-climatological conditions in the collection areas indicated the preferences of cherimoya and highland papayas in their natural environment, and were used, combined with GIS studies, to determine the potential cultivation zones. INTRODUCTION The Andean region with its striking eco-geographical contrasts is generally acknowledged as an important centre of biodiversity and is described as one of the eight centres of plant diversity as defined by Vavilov (Vavilov and Chester, 1950). Ecuador alone accounts for 16,087 plants species (Jorgensen and Leon-Yanez, 1999), being the highest plant diversity of the world per area unit. Within this rich plant biodiversity, several species are known as agricultural or horticultural crops. A lot of these crops however are considered as under-utilised (Izquierdo and Roca, 1998), due to “botanical colonialism” and have often been replaced by crops from Asia, Mexico and Europe Proc. IS on Sust. Use Of Plant Biodiv. Eds. E. Duzyaman Y Badillo et al., 2000) and must be considered as a hot spot for Vasconcella research. In southern Ecuador, Vasconcella cundinamarcensis, V. stipulata and the natural hybrid between these species V. × heilbornii are common and can be found in wild and in backyard gardens. Other less common highland papayas include V. candicans, V. microcarpa, V. monoica, V. palandensis, V. parviflora and V. weberbaueri. Consumption of highland papayas is common in the Andes where fruits are eaten fresh, roasted, in juices, in marmalades or in preserves (Van den Eynden et al., 1999). Only babaco, V. × heilbornii ‘Babaco’, is already commercially developed. It was introduced as a new crop in New Zealand in 1973 (Harman, 1983) from where it spread in the eighties to Australia (Cossio, 1988), Italy (Ferrara et al., 1993), Spain (Merino Merino, 1989), France (CTIFL, 1992), South Africa (Wiid, 1994) and even Switzerland (Evequoz, 1990) and Canada (Kempler et al., 1996) where greenhouse trials are being currently pursued. This study aimed at showing the potential of these native fruit crops. A study of the existing pomological variability in a centre of biodiversity gives valuable information to select potential accessions for future cultivation and/or breeding programmes. An edapho-climatological study of the targeted fruit species in their natural habitat has provided in fact valuable information on their soil and climate preferences which can combined with GISbe used to establish potential cultivation zones. A study of the papain content of highland papayas shows an even broader perspectives for the exploitation of Vasconcella species. RESULTS AND DISCUSSION A collection and characterisation of 137 wild and semi-cultivated cherimoya accessions was carried out in southern Ecuador between January 1996 and March 1998. A large variability of pomological characteristics was encountered, typical for a centre of biodiversity (Scheldeman and Van Damme, 1999). A selection of the best accessions, based on low seed content showed that local accessions easily withstand preliminary comparison with commercial cultivars from Spain (‘Fino de Jete’), United States (‘Bays’ and ‘White’) and Chile (‘Bronceada’ and ‘Concha Lisa’) (Scheldeman et al., 1999). Locally selected cherimoya accessions clearly show higher fruit weight and lower seed

Southern Ecuador is considered to be a centre of biodiversity of the so-called highland papayas. In Southern Ecuador, this group, which comprises lesser-known Andean Caricaccae that grow, mostly in the wild, above 1000 mas1, consists of Carica pubescens (A. DC.) Solms-Laub., C. stipulata Badillo, C. x heilbornii Badillo, C. candicans A. Gray, C. weberbaueri Harms., C. parviflora (A. DC.) Solms-Laub., C. microcarpa Jacq, C. monoica Desf. and the new endemic species C. palandensis Badillo, Van den Eynden & Van Damme. At this moment only the natural hybrid C. x heilbornii nm. pentagona Badillo, commercially known as babaco, is getting attention on the continuously expanding subtropical fruit market. Natural hybridisation and presence of accessions of which taxonomical position (at the species level) remains unclear, combined with a limited number of botanical studies, suggest that the taxonomy of the Caricaceae in Southern Ecuador is still not completely explained. Nevertheless, local collections and characterisation studies show that, from an agronomical point of view, these highland papayas show a big potential for the future. Organoleptic characteristics of some accessions and species are very promising, especially for use as juices and marmalades. Making use of natural or artificial hybridisation can even expand this potential. Analyses of the activity of the proteolytic enzyme complex (papain) of these local accessions and species showed that the latex of the unripe fruit possessed up to 15 times more activity than papaya (Carica papaya L.) cultivars selected and grown for their high enzyme activity. This potential, which needs further detailed study, is increasingly under threat as population is increasing, putting pressure on fallow and forest land and concentrating agricultural systems on food and cash crops, consequently neglecting little known native fruit crops and reducing the natural vegetation in which they occur. A survey on local knowledge of these highland papayas showed that younger people have significantly less knowledge on them than older people proving the urgent need for further studies and conservation strategies.

Babaco (Carica pentagona Heilb.) : importance, origin and botany; adaptability and growing conditions; past and present research; commercial potential

The effects of growing media, pot size, number of stems, and plant density on fruit yields of greenhouse‐grown babaco plants (Carica × heilbornii Badillo n.m. pentagona (Heilborn)) were determined. No significant differences were found in the total yield or days to harvest between plants grown in sawdust and Peatlite (2 peat : 1 perlite), nor between plants grown in 23‐litre and 45‐litre pots, nor between two‐stemmed and single‐stemmed plants. However, two‐stemmed plants produced significantly more, but smaller, fruits/plant than single‐stemmed plants. The yield (fruit weight)/plant = 6.88 + 4.50/x r2 = 0.97, P < 0.05, fruit number/plant = 1/(0.050–0.0075/x)r2 = 0.79, P < 0.05, and fruit size (mean fruit weight) = 386 + 313‐x/0.86 r2 = 0.94, P < 0.05, decreased over plant densities ranging from 0.5 plants/m2 to 3.7 plants/m2. However, on an area basis, yield (fruit weight)/m2 = 1/(0.032 + 0.155‐x)r2 = 0.79, P < 0.05, and fruit number/m2 = ‐23.3 + 49x‐2 r2 = 0.98, P < 0.05, increased, indicating t...

Ovules of babaco [Carica pentagona (Heilborn) Badillo], 23 to 140 days old, were cultured to initiate regenerative callus. Callus developed from the integuments and possibly from the nucellus. Ovules of greater length and age produced more calli on White's medium or medium with half-strength MS salts than on full-strength MS. Ovules >60 days old that were chilled for 24 hours produced significantly more callus than fresh ovules -1·m-2) developed green areas that subsequently produced nodular structures. Nodular structures produced proembryonal structures that developed into mature somatic embryos when transferred to media containing either GA3 (0.1 mg·liter-1) plus activated charcoal (2.0 g·liter-1) or casein hydrolysate (200 mg·liter-1) plus IAA (0.5 mg·liter-1). Somatic embryos converted into plantlets when transferred to embryo conversion medium. Chemical names used: 1-H -indole-3-acetic acid (IAA); gibberellic acid (GA3).

The levels of ascorbic acid (AA) have been measured by means of an HPLC method in 11 different exotic fruits (avocado pear, babaco, feijoa, grapefruit, kiwi, kumquat, litchi, mango, papaya, passion fruit, pineapple) and, for comparative purposes, in two citrus fruits (lemon and orange). They were measured in the exotic fruits at two different stages of ripening: (i) immediately after purchasing from a local fresh fruit market, and (ii) after a one-week period of artificial ripening. The results show that all tropical fruits contain relatively high levels of AA (varying between 20 and 90 mg/100g), with the exceptions of avocado pear and feijoa (whose AA levels are markedly affected by oxidation processes). Moreover, the results show that there is a remarkable loss of AA content (usually 30–40%) after the one-week period of artificial ripening, in all the different tropical fruits considered. They seem to indicate that the process of artificial ripening, which is usually carried out during the short-term storage of exotic fruits, can affect the nutritional value of this kind of food as far as the concentration of the reduced form of vitamin C is concerned.

L'activite lipasique du latex brut de Io plante subtropicale de Babaco (Carica pentagona) est etudiee dans des reactions d'alcoolyse et d'esterification. Les resultats indiquent que le latex brut de Carica pentagona presente des proprietes biocatalytiques equivalentes au latex brut de Carica papaya dans des reactions de synthese telles que l'alcoolyse de triacylglycerols et la reaction d'esterification (les rendements de reaction sont respectivement 72,3% et 70,2% apres 3 h pour l'alcoolyse et 31,8% et 33,8% apres 24 h pour la reaction d'esterification). Par contre, la papaine brute commerciale donne des rendements de reaction beaucoup plus bas que les latex bruts des deux especes de Carica (28,9% en alcoolyse et 5,4% en esterification). (Resume d'auteur)