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  • Author or Editor: Juan Manuel Gonzalez-Gonzalez x
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Starfruit (Averrhoa carambola L.) is reproduced by seeds from `Criollo' cultivars. The replication of desirable agronomic traits is difficult when selected plants are from sexual reproduction. The heterogeneity of plants is observed as higher trees, irregular fresh fruit yield, variable fruit quality, differential insect pest and disease susceptibilities, and extended period for recovering the inversion. Vegetative propagation is an alternative for reducing the heterogeneity of starfruit trees. Four grafting methods for propagating starfruit in the coast of Colima, Mexico: splice-side graft, wedge graft, whip graft, and bud graft were evaluated. The experiment was carried out on the Tecoman campus of the Universidad de Colima. The ambient conditions were dry tropic (BS1). Seven-month-old rootstocks were obtained from Criollo seedlings, and the scion was obtained from a healthy 15-year-old `Miss' donor tree. The experiment was distributed under a completely randomized design. The splice-side graft had 70% success and was the best, bud graft had 40% success, wedge graft, had 5% success and whip graft 0% success, and was the least successful.

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We evaluated the effect of five doses (0, 500, 1000, 5000, and 10,000 ppm) of indole butyric acid (IBA) on the aerial layer induction root of Litchi (Litchi chinensis Sonn.). The experiment was conducted in the coastal zone of Tecoman, Colima, Mexico, at the La Perla farm (18°15'N; 103°52'W and 33 m above sea level). The ambient conditions were dry tropics with an average yearly rainfall of 710 mm and 26 °C annual medium temperature (BS1). The evaluated variables were: 1) the number of roots emitted by layer, and 2) percentage of layers taken root by treatment. The experiment was carried out under a randomized block arrangement. We used five treatments with 12 repetitions, considering one tree to be a block, in which five treatments were effected with four repetitions into every one tree utilized. Results of Duncan's test averaged 5%. The results obtained indicated that dose of 500 ppm was the best IBA level as the percentage of layers taken root by treatment (96.7%). They are statistically different.

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Soursop (Annonamuricata L.) is reproduced by seeds from `Criollo' cultivars in Mexico. The replication of desirable agronomic traits is difficult when selected plants are from sexual reproduction. The heterogeneity of plants is observed as taller trees, irregular fresh fruit yield, variable fruit quality, different insect pests, disease susceptibilities, and lower number of plants per hectare. There is an extended time period for recovering investments and commericialization problems due to fruit quality and price. Vegetative propagation is an alternative for reducing the heterogeneity of soursop trees. Three grafting methods were evaluated for propagating soursop in the dry tropic region of Colima, Mexico: 1) splice side graft; 2) wedge graft; and 3) bud graft. The experiment was carried out on the Tecoman Campus of the Universidad de Colima. Rootstocks were from 8-month-old healthy plants, 1-m tall and 1-cm diameter, obtained from `Criollo' seedlings, and the scions were obtained from a healthy 10-year-old `Sin Fibra' donor tree. This donor tree was selected for its excellent agronomic traits and fruit yield. Vigorous and terminal scions were used, disinfected with fungicide, and used the same day of excision. The experiment was distributed under a completely randomized design. Splice side grafting had 67% success after 60 days, while wedge grafting and bud grafting had 0% success.

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The responsible substances involved in the phenomenon of compability/incompatibility in Sapotaceae species during two phenological stages were elucidated. An experiment was carried out to determine the compatibility/incompatibility relationship between homografts and heterografts of Sapotaceae species during two phenological stages, and to identify the responsible substances involved in the phenomenon. In order to determine the compatibility/incompatibility between Sapotaceae species, heterograftings were made using the mamey [Calocarpumsapota(Jacq.) Merr.] as scion, and chicozapote [(Achrassapota(L.)] was used as rootstock. Grafting was conducted during the phenological stage of defoliation of the scion donor plant, as well as during budding. Homografts were also made using C. sapota on C. sapota in both phenological stages. Plant tissue samples were obtained from scions and rootstocks in both phenological stages, and they were used for HPLC analysis. Heterografts (C. sapota on A. sapota) showed 100% incompatibility in both stages, and lack of success during grafting was obtained; similar results were registered with the homografts (C. sapota on C. sapota) during the budding stage; however, during the defoliation stage, 80% successful grafting was obtained. The responsible substances involved in the phenomenon of compatibility/incompatibility using samples taken during the grafting day and 60 days after (C. sapota grafted on A. sapota during defoliation stage), were identified as catechin and epicatechin. Catechins are the responsible substances of incompatibility in the heterografts of C. sapota /A. sapotain both phenological stages, as well as during the budding stage in the homografts on C. sapota.

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The tomato (Lycopersicon esculentum Mill.), is native to South America. It occupies the second place in worldwide vegetable consumption. Because of this, the evaluation of tomato varieties for the fresh consumption is important. The Mexican production is 1,908,607 tons of fresh product (SAGARPA, 2004). In the state of Colima, production has a mean efficiency of 18.13 t·ha-1 (INEGI, 2000). The following genotypes were evaluated `Peralta', `Montijo', Pavia', `Grande River', and `Yaqui' (control). A randomized experimental block was used, with five treatments and four repetitions. The obtained results indicate that `Yaqui' (control) had the better yield of fresh fruit, with 37.5 t·ha-1, followed by `Peralta' (27.2t·ha-1), and `Montijo' (12.6 t·ha-1), respectively. The height of plant in `Yaqui' was 68.8 cm and 60.26 cm in `Pavia'. In the days to flowering, after showing a homogenous behavior, pronouncing itself up to 27 days after the transplant; whereas the variety `Grande River' was pronounced up to 40 days. With respect to the number of total fruits by plant, a highly significant difference was observed. `Yaqui' produced 91 fruits, with `Pavia' and `Peralta' producing 50 and 37 fruits per plant, respectively. In conclusion, `Yaqui' was the genotype with greater yield and vigor.

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Vegetables are important in Mexican agriculture because of the exportation opportunities made available by the opening of the Free Trade Agreement. Okra represents a potentially profitable crop, and it is important to understand its behavior in a predetermined environment, and determine its optimal sowing density. The present work was realized to evaluate three genotypes and three densities of okra plants in the production and quality of fresh fruit. The work was realized in the winter–spring cycle in the dry tropic region, using a randomized block design with a bifactorial of nine treatments. During the cultivation cycle, the vegetative and productive variables did not present changes in phenology, and only registered differences in plant height (58.4 and 57.6 cm., respectively) of PX 416543 and `Green Best', with a distance between plants of 18 cm. These results indicate that with increased densities of 41,600, 50,000, and 69,444 plants/ha, there were no differences in the number and weight of fresh fruit/plant. Nevertheless, with the production and support the quality of fresh fruit increased. We conclude that high densities of plants increase the total crop of fresh fruit per hectare without affecting quality. The variety PX 416543 presented the best vegetative and productive behavior.

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In world production of vegetables, the red tomato contributes 47% of the total production and occupies second place in world consumption. The objective of this research was to evaluate 13 genotypes of red tomato with high technology for horticultural production in the greenhouse. This study was realized in “Zamora” greenhouses in Quesería-Montitlán, Colima, Mexico. The evaluated materials were: `Sun', D-0289, D-2465, D-2467, D-2475, D-2503, D-2505, D-2512, D-2515, D-2534, D-2541, D-2552, D-7705, and, as control, the `Roman' variety. The tallest height was that of `Roman' plants, 2.46 m, vs. the height of the first cluster of fruits in D-2575 with 51 cm. With respect to largest number of fruits per cluster and total harvested, D-0289 stood out with four and 18 fruits per plant, respectively. In regard to fruit size, the genotypes D-0289 and D-2534 presented the largest equatorial and polar diameter, with 19.2 and 14.2 cm, respectively. For fruit weight, the genotypes `Sun' and D-0289 presented the largest weight with 160 and 151 g, respectively. We conclude that agronomic management influences production under technical systems. For vegetative and productive desirable characteristics, the genotypes `Roman', D-0289, and D-77055 were the more adaptable for production in the greenhouse.

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Plants in the genus Ficus are one of the most used in the ornamentals. it is also used for plant handcrafting such as braid, cylinders, and wall rockets, using a single plant or braiding some plants. The ficus are commonly asexually propagated by slip or shoots. There is the possibility to graft and to obtain plants with two levels of foliage, combining the color and texture. The objective of this research was to evaluate the grafting compatibility of varieties of Ficus benjamina, such as: Vivian, Winter green, and Antillean (green color) grafted on the variety Profit (white color) used as rootstock. The study was carried out under environmental conditions of the Mexican Dry Tropic in Tecomán, Colima, Mexico. The grafting method was by whip or tongue approximation. Bud sticks of the four varieties ≈70-cm long were used as scions. They were previously rooted in polyethylene bags containing 1.5 kg of coconut fiber used as rooting substrate. The rootstocks were grown long in soil until 1.5 m and when they reach similar diameter to the scions. The grafting height and diameter was ≈50-60 cm, and 2-2.6 cm, respectively. Five grafted plants were used as experimental unit, and the treatments were distributed in a completely randomized design with four replications. The variables estimated were: number of leaves after 28 and 35 days post-grafting, and percentage of grafting at 28 and 35 days post-grafting. The tree varieties were compatible with the rootstock, and no differences were obtained between the treatments (Tukey test P< 0.05); both three varieties exhibited 75% of grafting success, and `Antillean' had higher number of leaves, but the three varieties were statistically similar.

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The most common spread of this species is sexual or by seed. In normal conditions, the germination of the seeds of Anonaceae can increase with pregerminative treatments prior to sowing. The objective was to determine the best pregerminative treatment to increase germination of soursop seeds. This study was carried out under the the dry, tropic conditions of Tecomán, Colima, Mexico. The experimental design was completely random with 12 treatments: 1) dip in water for 24 hours; 2) dip in water for 24 hours + gibberellic acid (GA3) at 350 ppm; 3) dip in water for 24 hours + GA3 at 500 ppm; 4) dip in water for 24 hours + GA3 at 1000 ppm; 5) mechanical scarification; 6) dip in water for 24 hours + mechanical scarification; 7) mechanical scarification + GA3 at 350 ppm; 8) mechanical scarification + GA3 at 500 ppm; 9) mechanical scarification + GA3 at 1000 ppm; 10) GA3 at 350 ppm; 11) GA3 at 500 ppm; and 12) GA3 at 1000 ppm; and control. There were four repetitions with 10 seeds in each experimental unit. The evaluated variables were the percentage of germination and the number of days from planting to emergence. To record results, analysis of variance and Tukey's test averages were used. The major percentage of germination resulted from the seeds treated with soaking in water for 24 hours plus GA3 to 350 ppm, dip in water for 24 hours plus scarification and GA3 at 1000 ppm, and equalized statistically to the control. For the number of days from planting to emergence, the treatment with mechanical scarification + GA3 at 500 ppm was statistically better. The use of gibberellic acid with mechanical scarification diminishes the dormancy of soursop seeds, producing plants in a relatively short period.

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The hot pepper (Capsicum annuum L.) is a plant domesticated in Mesoamerica. Hot pepper is currently widespread worldwide, and its uses are varied, such as for flavoring, pigment base, and as a nutritional food resource. Mexico produces about 623,238 tons/year of fresh fruits in 136,398 ha; the State of Colima produced 17,181 tons in 676 ha, with a mean of 27 t·ha-1. The culture of hot pepper in Colima faces certain limitations to its productive potential, such as lack of fertile and well-drained soils, constant soil moisture, and being free of weeds during the first weeks after transplanting; and maintaining plant uniformity in transplantation. This last practice is carried out in the side bed, but there is a lack of scientific evidence about the requirements of luminosity in the seed nursery in order to accelerate improvement of plant quality for transplanting, and the impact on fruit yield. The aim of this study was to evaluate the effect of different levels of shading on germination and vegetative development of `Jalapeño' hot pepper under greenhouse conditions. Four levels of luminosity were evaluated using mesh fabrics in order to produce 90%, 75%, and 50% shade, and control (0%) without shading on the seed beds. A completely randomized design with four treatments and four replications was used. The shading treatments reduced the germination period in about 2 days; increased the percentage of germination with a range between 1.6% and 3.7%; increased the plant height 2.3, 4.8, 7.72, and 10.1 cm at 3, 7, 13, and 18 days postemergence; increased the root biomass about 7.1 g/plant, and 5.4 g of fresh foliage with the 90% shade treatment in comparison with control. Overall, a better agronomic performance of the `Jalapeño' hot pepper was obtained with 90% shading.

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