Research Article
Evaluation of the banana cultivars Zelig, Grande Naine and Gruesa under different environmental conditions in the Canary Islands
- Juan Cabrera Cabrera, Victor Galán Saúco
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- Published online by Cambridge University Press:
- 08 February 2006, pp. 357-369
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Introduction. A study was done to compare Gruesa, a local dwarf Cavendish selection, with two other cultivars of the Cavendish subgroup in the open air or under greenhouse conditions in two localities of the Canary Islands. Materials and methods. The trials were set up with the cultivars Zelig, Grande Naine and Gruesa in four plots on the northern slope: one outdoors and three under three different greenhouse covers (one with polyethylene lamina and the other two with different types of mesh), and in one outdoor plot on the southern slope of the island of Tenerife. Morphological, phenological and production characteristics were studied over three productive cycles. Results. Significant differences were found in both plant height (Grande Naine > Zelig > Gruesa) and pseudostem thickness (Gruesa > Grande Naine = Zelig). Each cultivar showed a stable [height:thickness] ratio, remaining the same in all trial conditions. Gruesa cycle length was longer than those of the other two cultivars, emitting more leaves until bunch emergency. Gruesa produced the most hands per bunch and the most fingers per hand. In all cultivars, finger length was directly related to pseudostem height. All three cultivars produced well, with fruits very similar in organoleptic traits. A reduction in cycle length and a slight increase in productivity were observed in the northern plot under the polyethylene cover compared with the plots under other covers and outdoors. Conclusion. Gruesa appears more recommendable than Zelig and Grande Naine for open-air plantations in windy localities.
A new Bactrocera species in Benin among mango fruit fly (Diptera: Tephritidae) species
- Jean-François Vayssières, Georg Goergen, Orphée Lokossou, Paulin Dossa, Cyrille Akponon
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- Published online by Cambridge University Press:
- 08 February 2006, pp. 371-377
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Introduction. Tephritidae have a major economic importance in the tropical areas. In Benin, we had only very little information available on the mango fruit fly species, except the demonstration of their damage. We therefore carried out the first investigations in Northern Benin during the mango season in 2005. Our objectives were to study fluctuations of tephritid populations in orchards and to assess mango fruit fly infestations and mango losses due to tephritid species. Materials and methods. Experiments were carried out in the Parakou area (Borgou department, Northern Benin). Fruit fly males were captured on mango trees, in two different orchards, with parapheromone traps. To sample and characterize fruit fly species involved in mango infestations, fruits of 17 cultivars were collected in mango orchards from February to June 2005; then, they were brought to the laboratory for emerging species identification. To assess the loss of fruits, sampling of different mango cultivars was achieved in the same orchards. Infested fruits were counted and eliminated; potentially infested fruits were dissected. Results and discussion. Among eight mango fruit fly species found in Benin, four can be considered as species of economic significance: Ceratitis cosyra, C. quinaria, C. silvestrii and Bactrocera invadens. During the dry season, C. cosyra was the most abundant, whereas B. invadens was the most numerous during the rainy season (abiotic factor), in phenological accordance with the ripening of the different mango varieties (biotic factor). From and after mid-May, B. invadens was found more frequently than C. cosyra in the traps and from emergence of infested mangos. Loss averages varied globally from 12% at the beginning of April to 50% in June. Conclusions. Most of the tephritid species found on mangos during our experiments had already been observed previously in other West African countries except B. invadens, an invasive species lately described. Ecological and behavioral studies will be necessary in order to plan and to apply optimal methods for controlling this new pest of major economic importance in West Africa.
Transferability of SSR markers from lychee (Litchi chinensis Sonn.) to pulasan (Nephelium ramboutan-ake L.)
- Chun Hock Sim, Mansor Clyde Mahani, Chee Yen Choong, Idris Salma
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- Published online by Cambridge University Press:
- 08 February 2006, pp. 379-385
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Introduction. Pulasan and lychee are from the same family and closely related, therefore the SSR markers are expected to be highly transferable between these two taxa. We investigated the transferability of 12 lychee (Litchi chinensis Sonn.) simple sequence repeat (SSR) loci to pulasan (Nephelium ramboutan-ake L.). Materials and methods. Genomic DNA was extracted from 20 accessions of pulasan for the PCR amplification of the SSR loci using 12 pairs of SSR primers derived from lychee. The PCR products were resolved on denaturing polyacrylamide gels. Results. The percentage of SSR transferability from lychee to pulasan was 58.3% and the percentage of polymorphic SSR markers was 25%. Discussion. The moderate transferability and low polymorphism rates suggest the possibility of interruptions within the repeat motif and mutations in the flanking sequences of SSR repeat motifs. Our results did not reveal a high rate of transferability between lychee and pulasan. However, this study showed that the SSR markers developed in lychee are a good source of molecular markers for pulasan.
Fruit and seed yields in chataigne (Artocarpus camansi Blanco) in Trinidad and Tobago
- Laura B. Roberts-Nkrumah
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- Published online by Cambridge University Press:
- 08 February 2006, pp. 387-393
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Introduction. The chataigne or breadnut, Artocarpus camansi Blanco, has high nutritive value but it is an under-utilised food source. Yield losses due to tree height and limited information on productivity are constraints to commercial production. Our study was undertaken to determine fruit yield and seed yield, the relationship between fruit size and seed yield, and the response of yield to pruning. Materials and methods. Fruit and seed yield data were collected from 1996 to 2002 from three seedling trees established at the University of the West Indies in Trinidad and Tobago in 1993. The trees were pruned in December 1998. Results. The highest fruit mass per tree (139.7 kg), fruit number per tree (126) and seed mass per tree (59 kg) were obtained in 5-year-old trees. Fruit and seed yields were significantly (P < 0.001) lower in the years after pruning. Fruit mass per tree was positively correlated with fruit number (r = 0.99). Seed mass per fruit was positively correlated with seed number per fruit (r = 0.87) and both variables had strong, positive correlations with mean fruit mass (r = 0.83 and r = 0.77, respectively) and fruit volume (r = 0.63 and r = 0.67, respectively). Discussion and conclusions. Chataigne fruit and seed yield potential is greater than originally estimated. Both are strongly related and selection for high seed number per fruit with more effective pollination, disease control and proper tree height management may further increase productivity. In the field, estimated fruit volume is the most practical indicator of seed yield.
Planting time and mulching influenced vegetative and reproductive traits in strawberry (Fragaria × ananassa Duch.) in India
- Rajbir Singh, Ram Roshan Sharma, Rajiv Kumar Jain
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- Published online by Cambridge University Press:
- 08 February 2006, pp. 395-403
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Introduction. Planting time is considered as one of the most important factors for successful strawberry cultivation. Traditionally, under north-Indian plains, strawberry is planted after the second week of October, which results in the availability of fruits for a month or so. With the use of plasticulture techniques, the planting time can be enhanced, which facilitates early and higher production, and enhances availability of the fruit for a longer period. Mulching is the most important cultural practice in strawberry, which influences plant growth, fruit yield and quality. Hence, studies were conducted to determine the influence of planting time and mulching on growth, flowering and fruiting behaviour, yield and quality of strawberry in northern plains of India. Materials and methods. Studies were conducted on ‘Chandler’ strawberry with three planting times (mid-September, mid-October and mid-November) as the main effect and three mulching materials (black polyethylene, clear polyethylene and paddy straw) as the sub-main effect in a split-plot design with three replications. Standard procedures were adopted for making observations on plant growth parameters, flowering and fruiting behaviour, yield and quality parameters under different treatment combinations. Results and discussion. Mid-September planting favoured vigorous growth, enhanced flowering and fruiting, which resulted in the production of the largest fruits and highest yield of the best quality. Among the three different mulch materials, plants mulched with black polyethylene had the best growth, fruit weight, yield and quality compared with those mulched with clear polyethylene or paddy straw mulch. The [planting time × mulching] interaction was also found to be significant for all measured parameters. Conclusion. Our study revealed that, in northern plains of India, to get an early and high yield of the best quality under a micro-irrigation system, Chandler strawberry could be planted in mid-September if mulched with black polyethylene.
Flowering and fruiting of cv. Pakistan mulberry under saline soil conditions in Egypt
- Ahmed A. El Obeidy
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- Published online by Cambridge University Press:
- 08 February 2006, pp. 405-411
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Introduction. The introduction of the elite variety of black mulberry under saline conditions could have a significant long-term impact on development in the impoverished rural areas. Materials and methods. Plants of the Pakistan mulberry cultivar were propagated by budding on Japanese mulberry seedlings. Trees were cultivated under saline soil conditions in Egypt. Results and discussion. Trees successfully bloomed and produced fruits after 2 years of budding. Intensive flowering and fruiting occurred in the third seasons. Four to six catkins developed on each branch or spur. Each catkin consisted of an average of 315 flowerlets, stacked on a peduncle. Fruits were found to be parthenocarpic. During ripening, fruits changed from the green stage to the ruby-red stage, then to the dark-purple stage. Fruit ripening began in the second week of March and extended to the third week of April. Ripe fruit ranged from (7.3 to 11.8) cm in length and from (1.3 to 1.5) cm in diameter. Fruit weight ranged from (8.3 to 10.2) g. TSS of the fruit juice ranged from (13.0 to 17.5) °Brix, while pH ranged from 3.1 to 3.36. Fruits contained 10.2% carbohydrates, 1.4% protein and 1.2% fibers. Fruits were found to be a good source of iron, potassium, calcium and phosphorus. Fruits contained a medium level of vitamin C. Average crop production per tree in the second and third seasons was (51 and 96) kg, respectively. Ripe fruits could not survive more than 5 days’ storage at room temperature, but survived 3 weeks of cold storage.