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The use of chemicals to control vegetative growth of fruit trees at the Tree Fruit Research Laboratory in Wenatchee, Wash, began 25 years ago. Vegetative growth of apple seedlings in greenhouse trials was first controlled with foliar applications of butanedioic acid mono (2,2-dimethylhydrazide) (daminozide) (B-9, Alar). Field trials then were conducted on both apple and young cherry trees (3, 4). Daminozide also has been used to improve annual return blooming and fruit set, promote red skin color development, delay maturity, and improve storability of apple cultivars. Often, the high rates needed to control vegetative growth have reduced fruit size and fruit length, resulting in flat fruit shape (4, 13, 28). The latter phenomenon is important, for ‘Delicious’ apple for which “typiness” is a strong marketing characteristic and therefore an economic benefit. This paper presents results of continuing research on the control of excessive vegetative growth of deciduous fruit trees.

Open Access

Abstract

Pot-grown ‘Angie Physic’ hibiscus (Hibiscus rosa-sinensis L.) plants at the tight bud and blooming stages were stored in darkness for 3, 6, or 9 days at 4.5, 10.0, 15.5, 21.0, 26.5, or 32.0C, and then placed in a greenhouse for 21 days. Plants showed the least amount of damage at 10.0 or 15.5C or when stored for 3 days. Plants stored at 10.0 or 15.5C had delayed flowering, larger and more flowers, less flower bud and leaf abscission, and a higher plant quality. Storage for 6 or 9 days resulted in plants with smaller and fewer flowers, greater bud and leaf abscission, less fresh weight, and a lower quality.

Open Access

Abstract

‘Harglow’ is an attractive, high-quality, medium-sized apricot (Prunus armeniaca L.) introduced in 1982 for the Ontario fresh market but also suitable for commercial processing and for home preserves. The tree is cold-hardy, late-blooming, moderately productive, and tolerant to perennial canker (Leucostoma spp.). The fruit are resistant to brown rot [Moniliniafructicola (Wint.) Honey] and bacterial spot [Xanthomonas pruni (E.F. Sm.) Dows.], and moderately resistant to skin cracking and preharvest drop. They ripen in the midseason; 6 and 3 days, respectively, after ‘Goldcot’ and ‘Veecot’ and about 3 Aug. at Harrow. ‘Harglow’ is adapted to regions of southern Ontario where apricots are grown successfully. Early reports of its performance in Michigan and Pennsylvania are promising.

Open Access
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‘Prairifire’ is an attractive new ornamental crab apple with bright red-purple flowers, blooming 5–7 days later than other cultivars with that color, and immune or highly resistant to several destructive diseases of Malus.. Flower production is heavy and annual on both spurs and axillary buds on 1 year shoots. The flower color does not fade seriously nor develop an unattractive “muddy” appearance. Since axillary flowers develop somewhat later than do those on spurs, the flowering period is extended up to a week longer than if spurs were the only flowering sites. The small, dark-red fruits either dry on the tree or are eaten by birds, thus eliminating any clean-up problems from dropped fruits.

Open Access
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Effect of genotype on variation in chilling requirement among almond seed populations was studied. Pollen of different varieties used on the same seed tree changed embryo genotype and, subsequently, the chilling requirements of the populations of seeds produced. There was a direct correlation between time of bloom of seed and pollen parents and the length of chilling required by their offspring seeds. Chilling requirements were not significantly different in seed populations resulting from reciprocal crosses involving varieties of long and short chilling. Such seed populations had comparable genotypes but were exposed to different maternal effects. Embryo genotype was a controlling factor in determining seed chilling requirement in almond. A distinction between systems affecting inheritance of time of bloom in almond was shown in that ‘Tardy Nonpareil’, a late-blooming bud mutation of ‘Nonpareil’, transmits later bloom to its seedling offspring but did not transmit longer chilling to the seeds.

Open Access

Abstract

Morphological differences exist in pre- and postdormant inflorescence and fruit development of concentrated ripening selections Iowa 23-6214 and 26-6215 when compared with nonconcentrated ripening strawberry cultivars ‘Midway’ and ‘Cyclone’. Inflorescences sectioned before dormancy, however, revealed no characteristics considered indicative of concentrated ripening. Stylar development in secondary and tertiary flowers of greenhouse grown, concentrated ripening selections was retarded in the early post-dormant period. In single harvests in the field and greenhouse, these selections had higher percentages of ripe and partially ripe secondary and tertiary fruit than ‘Midway’ and ‘Cyclone’. A high abortion rate and/or arrested development in late-blooming flowers was characteristic of concentrated ripening selections. Pedicel length and inflorescence branching habit were not correlated with developmental or ripening rates.

Open Access

Abstract

Tropical lines of Phaseolus spp. planted in Hawaii in spring or early summer included types which bloomed in the usual 30-45 days and types which did not bloom until days had begun to shorten in the fall. Short day types bloomed at daylengths between 113/4 and 131/4 hr, with the majority blooming between 121/2 and 13 hr. P. vulgaris, P. lunatus, and P. calcaratus included both short-day and day-neutral types. All lines of P. aconitifolius, P. acutifolius, and P. angularis were day-neutral. Single lines of P. erythroloma and P. cf. stenolobus were short-day, and single lines of P. pilosus, P. radiatus, and P. bracteatus were day-neutral.

Open Access

With crosses between colchicine-induced tetraploid shashanbo (Vaccinium bracteatum section Bracteata) and tetraploid highbush blueberry ‘Spartan’ (Vaccinium corymbosum section Cyanococcus), intersectional hybrids were produced. The hybridity of these plants was confirmed based on DNA markers and morphological characteristics. The morphological characteristics, blooming date, and ripening period of the hybrids were intermediate between those of the parents. Ploidy analyses by flow cytometry and chromosome counting revealed that these hybrids were tetraploid. Four hybrids set fruit in the field and these two hybrids showed high pollen stainability. It was noteworthy that fruit of two hybrids had high soluble solids concentration compared with ‘Spartan’ and the fruit pulp of the hybrids was tinged with red as shashanbo. These hybrids could be useful in breeding new cultivars with high sugar content, abundant phytochemicals, extensive environmental adaptability as well as late flowering and fruit maturity.

Free access
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Blooming Phalaenopsis orchids have become a popular pot plant in recent years. Plants start producing spikes after experiencing cool air in early fall, bloom in early spring, and become limited in supply after April when market demand is strong. Deferring spiking and flowering by maintaining the greenhouse air constantly above 28°C is cost prohibitive. Previous research has discovered that plants must be given light while being exposed to cool air to induce spiking. In Fall 1994, 2-year old Phalaenopsis TAM Butterfly plants were exposed to repeated cycles of 1 day in darkness and another day in light (1D/1L), 4D/3L, 7D/7L, or 0D/7L (continuous lighted control) between 15 Sept. and 16 Dec. Each plant was removed from the treatment once it had started spiking. The control plants bloomed on 20 Jan. 1995, whereas the 4D/3L plants did not reach anthesis until April 17, nearly three months later. Flowering of the 1D/1L and 7D/7L plants was also deferred until early April. The treatments had no adverse effect on flower count or size. In 1995, 3-year old plants were exposed to 0D/7L (control), 2D/5L, 3D/4L, 4D/3L, or 5D/2L from 15 Sept. to 22 Jan. 1996. The control plants spiked on 17 Oct. and bloomed on 8 Feb. 1996 when spikes had just emerged from plants in the 5D/2L treatment. The 5D/2L plants are expected to bloom in late May or early June. The other treatments were not as effective as that in 1994 and resulted in blooming only 2–3 weeks after the untreated control. The results of this research will help producers to stagger or precisely program the time of flowering to meet the market demand.

Free access

A simple method to predict time from anthesis of perfect flowers to fruit maturity (full slip) and yield is presented here for muskmelon (Cucumis melo L.) grown in a northern climate. Developmental time for individual muskmelons from anthesis to full slip could be predicted from several heat unit formulas, depending on the temperature data set used. When temperature at 7.5 cm above soil level was used, the heat unit formula resulting in the lowest coefficient of variation (cv=6.9%) accumulated daily average temperatures with a base temperature of 11 °C and an upper threshold of 25 °C. With temperatures recorded at a meteorological station located 2 km from the experimental field, the method showing the lowest cv (8.9%) accumulated daily maximum temperatures with a base temperature of 15 °C. This latter method was improved by including a 60-degree-day lag for second cycle fruit. The proportion of fruit volume at full slip of 22 fruit from the first cycle could be described by a common Richards function (R 2=0.99). Although 65% of the plants produced two fruit cycles, fruit from the first cycle represented 72% of total yield in terms of number and mass. The blooming period of productive flowers lasted 34 days, each cycle overlapping and covering an equal period of 19 days. Counting the number of developing fruit >4 cm after 225 degree days from the start of anthesis (when 90% of the plants have at least one blooming perfect flower) could rapidly estimate the number of fruit that will reach maturity.

Free access