In January of 1990, 72 axillary bud were labeled on each of 6 carambola (Averrhoa carambola L.) trees. Six (6) buds per tree were harvested on a monthly basis and examined to determine their developmental state, which was classified as: reproductive, vegetative or undifferentiated. The number of reproductive buds peaked in July, October and November. The percentages of buds being reproductive during these 3 months ranged from 86% for October to 94% for November, with July intermediate at 91%. Vegetative bud production peaked during the period from February through June with 45% of buds vegetative, and again in August with 33% vegetative and December with 39% vegetative. More than 50% of buds examined were undifferentiated during the period from December through April and again in September. Periods with high percentages of undifferentiated buds preceded times with high percentages of either reproductive or vegetative buds. When a high percentage of buds were reproductive, the percentage of both vegetative and undifferentiated bud was low.
Steve Ritter and Mary Lamberts
Juan Manuel González-González, Salvador Guzmán-González, and Sergio Chavez-Luna
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.
Roberto Nuñez-Elisea and Jonathan H. Crane
Carambola (Averrhoa carambola L.) is native to the humid tropics of southeastern Asia, where it bears fruit year-round. In south Florida, winter conditions (strong winds and night temperatures below 15 °C) repress growth and flowering of the main commercial cultivar, Arkin, and fruit is produced from July to February. Off-season fruit would reach premium prices. We have previously demonstrated that selective pruning stimulates flowering of carambola at any time of the year. However, flowers produced during cool, windy weather have consistently failed to set fruit. This study was conducted in 1994–1995 to determine whether protected cultivation would help obtain off-season fruit. Four-year-old `Arkin' trees growing in 80-L containers were placed in a glasshouse or outdoors and pruned in November or December to force flowering during December–January. Glasshouse night temperatures during the winter were above 20 °C. All trees flowered in response to pruning. Outdoor trees produced less than one fruit per tree in late March to late April. Glasshouse trees produced 2.3 to 6.1 fruit per tree, 2 to 3 weeks earlier than trees outdoors. In the glasshouse, more than 98% of fruit were seedless, whereas all fruit produced outdoors were seeded. Production of seedless fruit indoors was achieved in the absence of insect pollinators, and yields were low compared to those of outdoor trees during the summer (at least 25 fruit per tree). We speculate that, under protected cultivation, the use of synthetic bioregulators during anthesis and insect pollinators may help increase production of off-season seedless and seeded fruit, respectively.
J. Siller, M. Muy, E. Araiza, M. Báez, R. Garcia, R. Báez, and J. Diaz
Carambola fruit collected at the dark-green, light-green, color-break, and ripe stages were evaluated during storage at 21C for up to 10 days. Fruit size, weight, postharvest changes in color, compositional characteristics, CO2 production, ethylene evolution, and weight loss were monitored daily. Fruit size ranged between 78 to 82 mm. Peel color luminosity and chroma values increased with maturity stage, while hue values decreased. However, hue and chroma values of the four ripening stages tended to decrease with storage time. Weight loss and fruit flesh firmness were both affected by storage time and ripening stage, and ranged among the maturity stages from 5.1% to 6.7% and from 2.11 to 0.94 kg-f, respectively. On dark-green fruit, total soluble solids and titratable acidity were 4.89° Brix and 0.808%, respectively. Fruit collected at the ripe stage presented values of 6.7° Brix and 0.412% titratable acidity. None of the fruit among maturity stages changed significantly during storage on these parameters. Carbon dioxide production increased from 6.06 to 21.83 ml CO2/kg-h during storage time among maturity stages and always was highest on ripe fruit. Fruit harvested at the color-break and ripe stages produced ethylene after 9 and 6 days, respectively, and ranged from 1.15 to 3.92 μl·kg–1·h–1.
There is a scarcity of information on how carambola (Averrhoa carambola) cultivars perform in various agroenvironments. Nine carambola cultivars—Arkin, B-10, B-16, B-17, Kajang, Kari, Lara, Sri Kembangan, and Thai Knight—grown on an Oxisol, an Ultisol, and a Mollisol were evaluated for 4 years under intensive management at Isabela, Corozal, and Juana Díaz, PR, respectively. There were no significant differences in number and weight of marketable fruit per hectare area among locations averaging 258,761 fruit/ha and 30,978 kg·ha−1, respectively. There were no significant differences of marketable fruit weight per hectare among highest yielding cultivars B-17, Thai Knight, and Sri Kembangan between locations. The average marketable fruit weight for these highest-yielding cultivars was 36,060 kg·ha−1. ‘Arkin’ and ‘B-16’ were the lowest yielding cultivars, averaging 23,490 kg·ha−1 of marketable fruit. ‘Kari’ produced significantly longer fruit at all locations, whereas ‘B-16’ produced the shortest fruit. Significantly higher soluble solids concentration values were obtained from fruit of ‘B-17’ at all locations, whereas lower values were obtained from those of ‘Arkin’. Overall, cultivars were highly adaptable to the diverse agroenvironments in which they were planted. The fact that ‘B-17’ had high production of marketable fruit, high marketable yield, and high soluble solids concentration at all locations makes this cultivar suitable for planting in diverse agroenvironments.
Bruce Schaffer, Frederick S. Davies, and Jonathan H. Crane
The effects of flooding calcareous soil on physiology and growth have been studied for several subtropical and tropical fruit crops including avocado (Persea americana Mill.), mango (Mangifera indica L.), carambola (Averrhoa carambola L.), and several Annona species. In calcareous soils that have a high pH, short-term flooding can actually be beneficial to subtropical and tropical fruit crops by increasing the solubility of particle-bound nutrient elements such as Fe, Mn and Mg due to flooding-induced decreases in soil pH. Additionally, flooding reduces the redox potential in the soil, resulting in Fe being reduced from Fe3+ to Fe2+, which is the cation metabolized by plants. As with other woody perennial crops, one of the early physiological responses of subtropical and tropical fruit trees to flooding is a decrease in stomatal conductance and net CO2 assimilation. If the flooding period is prolonged, lack of O2 (anoxia) in the soil results in a reduction of root and shoot growth, wilting, decreased nutrient uptake and eventual death. The flooding duration required to cause tree mortality varies among species, among cultivars within species, and with environmental conditions, particularly temperature. Several tropical and subtropical fruit crops have anatomical or morphological adaptations to tolerate prolonged flooding, such as development of hypertrophied stem lenticels, adventitious rooting or formation of porous aerenchyma tissue. For grafted trees, flooding-tolerance is conferred by the rootstock and not the scion. Therefore there is a possibility to increase flood tolerance of subtropical and tropical fruit crops by identifying or developing flood-tolerant rootstocks.
Ricardo Goenaga* and Edmundo Rivera
Nine carambola (Averrhoa carambola) cultivars grown on an Oxisol, Ultisol, and Mollisol were evaluated for 2 years under intensive management at Isabela, Corozal and Juana Diaz, Puerto Rico, respectively. There were no significant differences in number and weight of marketable fruits per hectare between Corozal and Isabela; average values for both locations were 249,824 fruits/ha and 29,864 kg/ha. At Juana Diaz these values were 196,254 fruits/ha and 24,339 kg/ha, respectively. There were no significant differences in weight of marketable fruit per hectare among cultivars B-17, Thai Knight, B-10, Sri Kembangan, and Kajang between locations. The average marketable fruit weight for these higher yielding cultivars was 31,457 kg/ha. Cultivar Kari produced significantly longer fruits at all locations, whereas cultivar B-16 produced the shortest fruits. Significantly higher brix values were obtained from fruits of cultivar B-17 at all locations whereas lower values were obtained from those of Arkin.
Thomas E. Marler and Michael V. Mickelbart
Growth response of containerized carambola (Averrhoa carambola L.) seedlings to GA applied to trunks in lanolin paste were studied under glasshouse conditions. Gibberellic acid at 0, 250, 500, or 750 mg·liter and an untreated control (no lanolin) were used. Internode length and increases in plant height and trunk cross-sectional area (TCA) did not differ for control and 0 mg·liter plants, but mostly increased with concentration of GA. Increase in TCA was determined in a second study with control and treated plants, using 500 mg GA/liter. Mean recommended graftable size (7 mm) was reached in 47 days in plants that were GA treated, and 93 days in control plants, suggesting that GA may be used to shorten nursery time for producing graftable carambola seedlings. Chemical name used: gibberellic acid (GA.,+,).
Thomas E. Marler and Yasmina Zozor
Growth and leaf gas-exchange responses of carambola (Averrhoa carambola L.) seedlings to wind or seismic stress were studied under glasshouse conditions. Forty days of twice daily seismic stress applied for 10 seconds consistently reduced carambola height, leaf area, dry weight, relative growth rate, and leaf-area ratio, but increased trunk cross-sectional area compared with plants receiving no seismic stress. Fifty-one days of wind load reduced plant height, leaf area, dry weight, trunk cross-sectional area, net assimilation rate, relative growth rate, leaf-area ratio, and stomatal conductance compared with plants receiving no wind stress. Morphological appearance was similar for plants receiving wind or seismic stress. Net CO2 assimilation of carambola leaflets was reduced by 30 minutes of wind load for up to 6 hours following the stress. Results suggest that wind may reduce carambola growth at least partially by influencing leaf gas exchange or by the mechanical stress associated with wind.
Thomas E. Marler and Patrick D. Lawton
Leaflets of `Arkin', `B-10', `Kary', and `Sri Kembangan' carambola (Averrhoa carambola L.) trees were restrained in a horizontal position for 3.5 h during midday under full sun conditions to determine the influence of overriding natural leaflet movement on adaxial chlorophyll fluorescence and temperature. Induced chlorophyll fluorescence obtained after 30 minutes of dark adaptation following the period of full sun exposure was affected by leaflet movement. Restrained leaflets exhibited a variable fluorescence (Fv)/peak fluorescence (Fm) of 0.48, while that of unrestrained leaflets was 0.65. Adaxial leaflet temperature of restrained leaflets was 6C higher than that of leaflets that were allowed to move. The influence of leaflet movement on temperature or chlorophyll fluorescence was not different among the four cultivars. However, mean Fv/Fm of `Kary' and `Sri Kembangan' was lower than that of `B-10'. Our results indicate that the ability of carambola to change leaflet angle leads to lower temperature and higher photochemical efficiency than occurs when leaflets are not allowed to move naturally (vertically orient) under full sun conditions.