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Ten tomato cultigens were crossed with L. peruvianum accessions PI 126443 and PI 129152. Fruit (536 total) were harvested between 15 and 65 days after anthesis (DAA). Culturable embryos were obtained from 13% of the fruit. There were 140 embryos plated, from which 36 plants were obtained (7% of fruit, 26% of embryos plated). 'Campbell 28', Fla. 7217, and Fla. 7182 were the most efficient tomato lines for producing F1 plants, there was no difference between the L. peruvianum accessions. No embryos were obtained beyond 57 DAA. No trend in embryo viability was detected between 15 and 56 DAA. Of 248 backcross fruit, 94 embryos were plated (38% of fruit) and 15 plants were obtained (6% of fruit, 16% of embryos plated). Female parents with the best percentage of plants per fruit crossed were Fla. 7217, Fla. 7215, and 'Campbell 28' with 15, 8, and 7%, respectively. No plants were obtained from 45 crosses on Fla. 7182.

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Physiological disorders of apples, such as cork spot and bitter pit, are a result of low soil calcium, low or excessive soil moisture, large fruit size, and environmental conditions. We report on the effect of microirrigation treatments on apple fruit when irrigation is applied as water alone or water plus a calcium (Ca)/boron (B) solution with applications applied over the tree canopy or under the tree canopy. Apples were harvested from trees in their 4th to 7th leaf and the number of fruit and size of fruit varied from year to year. In most years, there were no significant differences among treatments for fruit Ca. Fruit B was significantly higher in treatments where B was applied through the irrigation. Fruit N/Ca levels were lower when the fruit size was smaller, which was due to a higher number of fruit per tree. Year to year variations in fruit Ca levels also were likely to temperature, humidity, rainfall, fruit size, and shoot growth.

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Abstract

Yields and size distribution of sweetpotato (Ipomoea batatas Lam) propagated from root pieces were similar to those grown from sprouts when comparable stands were obtained.

Open Access

Abstract

The concentration and total content of P, K, Ca, Mg, N, Fe, Mn, and B in storage roots and in vines of sweet potatoes [Ipomoea batatas (L.) Lam.] was followed for a 14 week period beginning 2 months after planting. The concentration of N, P, K, Mn, and Mg in the vines and N, P, and K in the roots decreased slightly during the period. Other elements showed no definite seasonal trends. Total uptake by the vines showed little change after the second sampling period

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Abstract

Ethephon applications at 250 to 1500 ppm rates during final swell of ‘Babygold-9’, a clingstone peach, accelerated maturation as measured by firmness and skin and flesh color changes and reduced titratable acidity. High rates were phytotoxic and detrimental to fruit quality. Increased immature fruit abscission appears to limit the practical use of ethephon at this growth stage in peach.

Open Access

Abstract

Four cultivars of sweet potatoes (Ipomoea batatas Lam.) were sampled bi-weekly during the period of storage root development Although the root weight increased nearly 8-fold during the sampling period there was only a 35% increase in the number of roots. Alcohol insoluble solids (AIS) and % dry matter generally showed a slight increase throughout the season and specific gravity a slight decrease. Total sugars and reducing sugars failed to show a trend. In contrast, the processed roots tended to become softer as the season progressed. Firmness was related to chronological age of roots rather than harvest date. The later the planting the higher were total and reducing sugars but planting date had no consistent effect on other raw product attributes.

Open Access
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Cyperus kyllingia and Cyperus brevifolius are problematic turfgrass weeds in Hawaii. Both are closely related weed species with similar morphology and growth characteristics. C. kyllingia appears to be a more successful weed with regards to interference than C. brevifolius. Greenhouse experiments were conducted to compare the levels of interference exerted by C. kyllingia and C. brevifolius upon Cynodon dactylon turfgrass. C. kyllingia reduced the growth of C. dactylon by about 50 %, while C. brevifolius did not significantly reduce C. dactylon growth. These results correspond with the chemical profiles of C. kyllingia and C. brevifolius. Analysis has shown that C. kyllingia contains two sesquiterpenes which have been identified as potentially allelopathic components of Cyperus rotundus. C. brevifolius contains waxes and the two sesquiterpenes found in C. kyllingia are absent. This suggests that allelopathy may be the mechanism responsible for the different levels of interference exhibited by C. kyllingia and C. brevifolius, and these species may provide an important model for the study of allelopathy.

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Seed dormancy is an evolutionary adaptation for increasing seedling survival by delaying germination and is found in many families of seed plants. Although dormancy is ecologically important, it becomes problematic during agronomic production and restoration. Torrid panicgrass (Panicum torridum) is a native Hawaiian annual grass that has been identified as a re-vegetation candidate for seasonally dry areas. Torrid panicgrass seed appears to possess a nondeep to intermediate physiological dormancy. This research aimed to characterize dormancy relief parameters by 1) evaluating exogenous hormonal, reactive oxygen intermediates, and simulated combustion product treatments; and 2) determining optimized storage conditions of relative humidity (RH) and temperature over a 10-month duration. Results indicate that all exogenous chemical treatments tested were not effective at relieving the dormancy present in torrid panicgrass. Optimal storage conditions to relieve dormancy were found with seeds equilibrated to 12% RH, stored at 30 °C for a period of 8 months resulting in 55% germination. Maintenance of viability for long-term storage up to 10 months was best achieved with seeds stored at 12% RH at 10, 20, or 30 °C.

Open Access

Abstract

One hundred tomato (Lycopersicon esculentum Mill.) strains were grown under low-K stress (0.071 mm K) in the absence and presence of added Na to identify strain differences in efficient K use, efficient substitution of Na for K, and upper leaf Na accumulation. Five strains, selected as representing extreme differences for K efficiency and Na substitution capacity, were used as parents to create a series of F1, F2, and backcross generations to study the inheritance of K efficiency, Na substitution, and upper leaf Na accumulation of tomatoes grown under low-K stress. Reciprocal differences in the F1 generation were relatively unimportant in the inheritance of K efficiency, Na substitution capacity, and Na accumulation. K efficiency in the absence of Na was a trait of low heritability, with highly significant additive, dominance, and additive × additive epistatic effects. Na substitution capacity was highly heritable, with highly significant additive and dominance effects. Na accumulation also was highly heritable, with highly significant additive effects. Moderately high correlations were observed between Na accumulation and Na substitution capacity within genetically segregating generations.

Open Access