observed for decades and was described as early as the 1930s ( Bliss, 1937 ). This phenomenon, previously described as “cross-cut” or “V-cut,” is expressed as cuts in the fruit stalk, which cause the drying and dropping of fruit bunches. These symptoms have
Mangoes ( Mangifera indica ) represent a small part of the fresh-cut industry but their popularity is growing, as reflected by the increase in sales by 8% between 2013 and 2017 in the United States ( National Mango Board, 2017 ), and recently
The fresh-cut apple industry has taken on momentum and has established itself as a new category in the fresh-cut fruit market segment ( Clement, 2004 ). In the growth and development of a new sector, there is a need to improve on existing cultivars
. 2014. Leaves were removed before the shoots were rinsed with tap water for 2 h and cut into 1- to 1.5-cm lengths with one or two nodes. Microshoot establishment. Nodal segments were surface disinfected in 70% (v/v) ethanol for 30 s and washed with
Secondary bloom provides fireblight infection sites in pears (Pyrus communis L.) growing in the western U.S. Five types of secondary bloom occur in `Bartlett', and one of these, Type V, occurs mainly as a result of pruning. We examined the effect of pruning dates (Feb. to Sept. 1999), shoot age ranging from 1 to 4 years old, and type of pruning cut (i.e., heading, stubbing, or thinning) on Type V secondary bloom. Pruning date was a significant factor determining whether Type V would occur. There was a greater chance for Type V to occur from pruning in February or March than for pruning from May through September. There was an increase in Type V with increase in shoot age when pruning 11 Feb., 17 Mar., 14 May, or 11 Aug. There was no shoot age effect when pruning 18 June or 30 Sept. Type of pruning cut affected the number of Type V that occurred when pruning 14 May, 18 June, or 11 Aug., but the effect of type of pruning cut was inconsistent between these dates. There was no effect of type of pruning cut when pruning 11 Feb., 17 Mar., or 30 Sept. These results indicate that summer or postharvest pruning may reduce the number of Type V secondary bloom, particularly on shoots older than one year. This information can be used to develop a pruning strategy that reduces the number of Type V secondary bloom and potentially the number of fireblight infection sites.
samples (≈1 cm long) cut from the root tips of each plant on Phytophthora selective medium (PARPH-V8) ( Ferguson and Jeffers, 1999 ) or Rhizoctonia semi-selective medium ( Gutierrez et al., 2001 ). The number of root pieces showing P. nicotianae
Abstract
Frequent irrigation regimes, and cool storage increased the sensitivity of carnation cut flowers to ethylene which was reflected by a shorter residual flower life. A combination of cytokinins, 0.23 m<sc>M</sc> kinetin or isopentyl adenine (IPA), with 5% w/v sucrose reduced the sensitivity to ethylene and increased longevity 2 to 2.6 times, respectively. The reversible and irreversible wilting response to ethylene is discussed.
Premature deterioration and/or wilting of cut flowers such as roses (“bent neck”) has been attributed to vascular blockage within the cut stem. Vascular blockage has been attributed to both the proliferation of bacteria in the cut flower water and/or to products exuded by the stem. Separation of these causative agents is prevented by the inability to obtain intact microbe-free flowers. With the objective to produce microbe-free flowers, 36 miniature rose cultivars were screened for their capacity to flower in vitro. Stem segments containing single lateral buds were surface sterilized in 1.05% (v/v) sodium hypochlorite and rinsed three times in sterile distilled deionized water. Buds were established on medium consisting of Murashige and Skoog mineral salts, Woody Plant Medium organics, 3.0% (w/v) sucrose, 0.5 mg/liter benzyladenine, 0.1 mg/liter indole-3-acetic acid, and 50 mg/liter each citric and ascorbic acids. Medium was solidified with 1.5 g/liter gelrite and 4 g/liter TC® agar. Of the 36 cultivars screened, eight (22%) grew poorly in vitro. Of the 28 responsive cultivars, 14 (50%) produced flower buds in vitro However, only six cultivars produced open flowers in vitro.
Current propagation techniques for grapevine rootstocks involve rooting cuttings from dormant or actively growing canes and require relatively large amounts of propagation wood. We report an alternative method involving high-frequency, in vitro rooting of single-node cuttings that can be used when limited amounts of plant material are available. Propagation material was taken from greenhouse-grown plants of Vitis arizonica, V. treleasei, and V. treleasei interspecific hybrids (with V. acerifolia, V. arizonica, and/or V. doaniana) collected from the wild in New Mexico. Shoots were cut into one-node sections and surface sterilized in 25% commercial bleach for 10 minutes followed by three rinses in sterile water. The cuttings were placed on media containing half-strength Murashige and Skoog (MS) salts, MS vitamins, 20 g·L-1 sucrose, 2 g·L-1 phytagel, pH 5.8. The cuttings were incubated at 27 °C under a 16-hour photoperiod. Vitis vinifera `Cabernet Sauvignon' and `Chardonnay' were also rooted under similar conditions. All genotypes investigated rooted, but with varying frequency. Particular selections from the genotypes collected from the wild rooted at high frequency (>84% of cuttings rooted), while 66% of `Cabernet Sauvignon' and `Chardonnay' cuttings rooted. Plants were successfully established in the greenhouse. In vitro rooting of single-node cuttings appears to be a valid alternative for grapevine propagation.
Secondary or “rat-tail” bloom, a major site for fireblight infection of `Bartlett' pear, comprised 10% of the total bloom in 1997 and 20% in 1998. We are striving to find production practices that can be economically applied to reduce the number of “rat-tails.” Of the five known types of secondary clusters in pear, four occur on `Bartlett', the most numerous being types I and V. Type I rat-tails occur on the bourse at the base of normal clusters and bloom from 10 to 30 days after normal bloom. Type V rat-tails occur mostly at pruning sites and have one to three flowers per cluster, blooming 20 to 50 days after normal bloom. GA 3 or GA4+7 + BA were applied at 100 mg•L-1 in 1997 to reduce rat-tail bloom in 1998. In 1998, neither GA3 nor GA4+7 + BA had an effect on normal bloom or type I rattails. GA3 reduced type V rat-tails when applied at either 2 June, 2 July, or 15 Aug. but had no effect on type V clusters when applied at full bloom, petal fall, 16 June, or 15 July. GA4+7 + BA reduced the number of type V rat-tails when applied at either 2 June, 16 June, 2 July, and 15 July but had no effect when applied at full bloom, petal fall, or 15 Aug. Dormant pruning horizontal shoots resulted in as many rat-tails as vertical shoots, and heading cuts a similar number as stubbing cuts. Dormant pruning 1-year wood resulted in fewer rat-tails than 2-year wood. Summer pruning 21 or 49 days after bloom resulted in fewer rat-tails than pruning 10 days after harvest, but was similar to pruning 89 days after bloom. These and other results from ongoing work will be presented toward development of an integrated fire blight reduction strategy.