Deborah Buszard

Current state of cold hardiness research on fruit crops

This article gives an overview of the current state of cold hardiness research in fruit crops by reviewing the recently published studies on cold hardiness of both tree fruit and berry crops. Topics discussed include cold hardiness of fruit species, cultivars and different plant organs, biophysical and biochemical aspects of hardiness, evaluation of hardiness, as well as endogenous, cultural and environmental factors affecting cold hardiness in these species. Lack of cold hardiness is a major limiting factor for production of fruit crops in many regions of the world and improved cold hardiness one of the major objectives in numerous breeding programs and research projects. Screening cultivars or selections for cold hardiness is commonly done, and different methods applied to the evaluation of hardiness are discussed. The physical limit of deep supercooling may be a restricting factor for expanding the production of some fruit crops, such as Prunus species and pear. As for biochemical aspects, a relationsh...

Effect of three vesicular‐arbuscular mycorrhizae species and phosphorus on reproductive and vegetative growth of three strawberry cultivars 1

Abstract A study was undertaken to evaluate the yield, fruit size, and vegetative growth of three strawberry cultivars inoculated with three vesicular‐arbuscular mycorrhizal (VAM) species at three phosphorus (P) fertility levels. Vesicular‐arbuscular mycorrhiza inoculation and P fertility had no effect on inflorescence or flower number, total yield, fruit weight, or crown number. Higher levels of P did not increased total dry shoot weight, total fresh shoot, weight leaf area, total dry root weight, and leaf number in the present of VAM. However, the cultivars responded differently to VAM inoculation. Vesicular‐ arbuscular mycorrhiza inoculation in combination with P at all levels increased total dry and fresh shoot weight, leaf area, and leaf number compared to application of P alone. The results indicated that it may be possible to increase strawberry stolon production by inoculating the strawberry plants with VAM, a technique which might be useful in nurseries to produce certified strawberry plants.

In vitro screening for cold hardiness of raspberry cultivars

Raspberry (Rubus idaeus L.) cultivars ‘Festival’, ‘Titan’ and ‘Willamette’ were cultured in vitro on three different media: (A) MS medium supplemented with 1.0 mg l-1 BAP and 0.1 mg l-1 IBA, (B) MS medium without growth regulators, and (C) MS medium with reduced sucrose (10 g l-1), and exposed to different low temperature acclimation treatments: (1) control, no acclimation, (2) 1 week at +15 °C, 1 week at +2 °C, 24 h at -2 °C and 3 days at +2 °C, and (3) 2 weeks at +15 °C, 2 weeks at +2 °C, 24 h at −2 °C and 3 days at +2 °C. After acclimation, shoot moisture content was measured, and cold hardiness (LT50) was determined by controlled freezing. Shoot moisture content was generally lower on culture medium B compared to the other media, but not affected by acclimation treatment. In non-acclimated plants, medium composition had no effect on cold hardiness and no cultivar differences in hardiness were observed. After acclimation, plants on culture medium B were on average more cold hardy than on the other media. Acclimation treatment 3 on media A and B allowed the best discrimination between the hardy cultivar ‘Festival’ and less cold hardy ‘Titan’ and ‘Willamette’. When acclimation treatments were tested further using 11 raspberry cultivars with different levels of cold hardiness, discrimination between cultivars was satisfactory only after acclimation treatment 3 on culture medium B.

Seasonal variation of hydrophilic, hydrophobic, and charged amino acids in developing apple flower buds 1

Abstract An increase in polar amino acids especially in hydrophilic and charged amino acids and a decrease in hydrophobic amino acids were observed in developing apple flower buds from July to November (beginning of dormancy). This suggests that polar amino acids may play a role in dormancy of apple flower buds similar to that of other polar substances. A 2nd‐degree polynomial was observed for hydrophilic, hydrophobic, and charged amino acid content, during growth and development.

Sensory evaluation of six strawberry cultivars after machine harvest

In 1991 and 1992 four standard cultivars‘Kent’,‘Glooscap’,‘Bounty’ and‘Midway’ and the recent introductions‘Chambly’ and‘Oka’ were evaluated for appearance, texture and flavour attributes.‘Bounty’ was the only cultivar which ranked high for sweetness and high for strawberry, honey, and melon flavors, whereas‘Oka’ ranked lowest. Sweetness was not significantly different among‘Chambly’,‘Glooscap’,‘Kent’, and‘Midway’.‘Glooscap’,‘Midway’,‘Kent’, and‘Oka’ were more acidic than‘Bounty’ and‘Chambly’. Chambly’ and‘Kent’ had pronounced raised achenes whereas those on‘Oka’ fruit were depressed which makes this cultivar unsuitable for mechanical harvesting. No pithy core was observed in‘Chambly’ and‘Glooscap’.‘Chambly’,‘Glooscap’,‘Bounty’ and‘Kent’ had bright skin while‘Midway’ and‘Oka’ had a dull appearance.‘Oka’ and‘Midway’ appeared less seedy than the others. Striation and white rings were observed in all cultivars, however, these were less conspicuous in the cultivars‘Oka’ and‘Midway.