treatments to maintain qualitative characteristics of kiwifruit during cold storage. Materials and Methods Plant material Mature, unripe kiwifruit ( Actinidia deliciosa cv. Hayward) of medium-sized (80 to 120 g) fruits, free from visible defects or decay
Shirin Shahkoomahally and Asghar Ramezanian
David L. Warfield and Edwin Seim
The root structure of kiwifruit was investigated by sequential trenching and eventual removal of whole vines. The vines had a shallow (30 to 60 cm.) spreading root system with few sinker roots. Roots extended beyond the canopy. Radial distribution of major roots arising from the crown was non-uniform. In several instances, roots mimicked the top by tying themselves into knots.
M. Cristina Pedroso, M. Margarida Oliveira, and M. Salomé S. Pais
Nodal segments and shoot tips of axenic shoot cultures of `Hayward' kiwifruit were inoculated on modified Murashige and Skoog (MS) medium supplemented with zeatin at 1 mg·liter-1 and IAA at 0.05 mg·liter-1 (H1) or on MS medium without growth regulators (H2). Inocula cultured on H2 medium all developed into normal plantlets, while those cultured on H1 medium developed into shoots, 18% of them abnormal. Rooting of H1 shoots was induced by a 24-h immersion in a solution of IRA at 20 mg·liter-1. H2 plantlets were directly transferred to soil. Statistical treatment of the results revealed no significant differences, in terms of plant development, between the two micropropagation methods used. However, the presence of a functional root system on 5-week-old H2 plantlets resulted in 100% plant survival, but only 70% of in vivo-rooted shoots from H1 survived. Nevertheless, H1 still allowed for an important reduction of costs and manipulation. Chemical names used: indole3-acetic acid (IAA).
Arlie A. Powell and Ed Tunnell
It has been shown that the `Hayward' kiwifruit requires ≈1000 chilling hours for satisfactory production of female flowers, leading to full cropping in the southeastern United States. Part of the area along the Gulf Coast frequently suffers from inadequate winter chilling, resulting in poor cropping of `Hayward'. Studies were conducted over a 4-year period in a mature `Hayward' planting near the Gulf Coast to evaluate the efficacy of hydrogen cyanamide sprays in replacing lack of chilling and improving cropping. Rates of 2%, 3%, and 4% (v/v) of 50% Dormex significantly increased yield, with the highest rate providing the maximum yield. Fruit size and overall fruit quality from Dormex treatments were good. Dormex sprays performed quite well when only 600 to 700 chilling hours were received in the test area.
F. Mencarelli, L. Lanzarotta, R. Massantini, and R. Botondi
Kiwifruits were picked by hand and gently placed in pulp trays. Impact tests were conducted by dropping the fruits from heights of 30 cm onto different sandpapers to provide a uniform abrasion surface. Abrasion tests were conducted by compressing the fruits with a fixed load of 3.5 N (Instron equipment) onto different sandpapers and pulling out the fruits. Compression test was performed by using the previous procedure with a fixed load of 4.5 N for different period of time (minutes). Increase of transpiration rate and ethylene production was observed in fruits abraded with sandpaper which slight wounded the peel. Impact onto sandpaper, caused the appearance of white lignifted filaments in the flesh. Increase in soluble solids and softness of flesh and core was observed in injured fruits. Healing process and polyamines effect will be discussed.
Domingos P.F. Almeida and Maria Helena Gomes
conditioned to recover their sensory properties. Materials and Methods Plant material. ‘Hayward’ kiwifruit [ Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa ] were harvested from a pergola-trained orchard located in
Nikolaos Koutinas, Thomas Sotiropoulos, Antonios Petridis, Dimitrios Almaliotis, Emmanuil Deligeorgis, Ioannis Therios, and Nikolaos Voulgarakis
several fruit quality attributes and nutritional status of the kiwifruit cultivar Tsechelidis. Materials and Methods The research was conducted in a commercial kiwifruit [ Actinidia deliciosa (A. chev.) C.F. Liang et A.R. Ferguson var. deliciosa
Timothy P. Hartmann, Justin J. Scheiner, Larry A. Stein, Andrew R. King, and Sam E. Feagely
Two-year-old, field-grown golden kiwifruit (Actinidia chinensis) and fuzzy kiwifruit (Actinidia deliciosa) plants were evaluated for injury following an early freeze event of −4.1 °C on 14 Nov. 2018 in Burleson County, TX. Plant material included seven cultivars: one seed-propagated [Sungold™ (ZESY002)] and three cutting-propagated golden kiwifruit (AU Golden Dragon, AU Golden Sunshine, CK03), and one seed-propagated (Hayward) and two cutting-propagated fuzzy kiwifruit (AU Authur and AU Fitzgerald). Observations were made 5 weeks after the frost event. Base trunk diameter (BD) and maximum trunk diameter damaged (MDD) provided a reference of plant size and crude measurement of damage intensity, as evident by presence of water-soaked necrotic and/or dehydrated tissue following the removal of a thin slice of periderm, vascular cambium, phloem, and xylem. Percent of base diameter damaged (PBDD) was calculated as MDD divided by BD and provided an assessment of damage, unbiased by plant size. Percent of shoot damaged (PSD) was visually evaluated as the percentage of entire shoot system exhibiting damage. In addition, presence of basal damage (DB) and basal cracking (CB) were recorded. A strong cultivar response was observed for BD, MDD, PBDD, and PSD. Mean cultivar values for PSD ranged from 79% and 19% for AU Authur and Sungold™ seedlings, respectively, which represented extremes among cultivars. Fuzzy kiwifruit exhibited greater injury (PBDD, PSD, DB, and CB) as compared with golden kiwifruit cultivars. Basal damage and basal cracking proved unique to fuzzy kiwifruit, as DB ranged from 0% in Sungold™ seedlings to 100% in fuzzy kiwifruit ‘AU Authur’ and ‘AU Fitzgerald’. In spite of having greater vigor, golden kiwifruit plants sustained less injury. Method of propagation had no effect on injury. PBDD and PSD proved to be reliable field assays for documenting injury, based on their strong correlation value (r = 0.92). Greater relative autumn frost tolerance of golden kiwifruit over fuzzy kiwifruit cultivars is previously unreported.
Shaolan Yang, Changjie Xu, Bo Zhang, Xian Li, and Kunsong Chen
members from kiwifruit and evaluate their response to ethylene and ASA. Materials and Methods Plant material. Kiwifruit ( Actinidia deliciosa cv. Bruno) fruit were harvested at commercial maturity with total soluble solids at around 7 ºBrix
Clint Wall, William Dozier, Robert C. Ebel, Bryan Wilkins, Floyd Woods, and Wheeler Foshee III
Actinidia deliciosa A. Chev. and A. chinensis Planch. are dioecious species that have vegetative and compound buds, with flower clusters produced in the leaf axils of the first four to six nodes. Male and female flowers are perfect