Current state of cold hardiness research on fruit crops

Abstract

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 relationship between carbohydrates and cold hardiness is most commonly found. Studies have also been made on different hardiness modifying cultural factors including rootstock, crop load, raised beds and application of growth regulators. The latter seems promising for some species. Cold hardiness is an extremely complex phenomenon and understanding different mechanisms involved is critical. Since hardiness is, however, primarily affected by genotype, developing cold-hardy fruit cultivars and effective screening methods for hardiness are essential. Finally, cultural practices may be improved to further enhance hardiness. Key words: Berries, cold hardiness, fruits, small fruits, stress, winter hardiness

Soluble Sugars and Sucrose-Metabolizing Enzymes Related to Cold Acclimation of Sweet Cherry Cultivars Grafted on Different Rootstocks

“…A range of different methods can be used to evaluate injury after artificial freezing in controlled conditions [5]. The most frequently used methods for freezing injury assessment are visual rating of injury and electrical conductivity (EC) of diffused electrolytes [6].…”

Evaluation of susceptibility of pear and plum cultivars to winter frost

“…Davarynejad et al (2009) indicated that the most sensitive organ of walnut genotypes was female buds, followed by male buds, vegetative buds, annual shoots and finally biannual shoots. Palonen and Buszard (1997) indicated that flower bud hardiness of apples did not seem related to hardiness of woody tissue. In P. davidiana the shoot was hard, however, the reproductive bud was sensitive (Ackerman 1969).…”

“…During an environmental stress like low temperatures, the osmotic regulation takes on a resistance role to cold by cell accumulation of (Palonen and Buszard 1997). …”

Genomics and Functional Genomics of Winter Low Temperature Tolerance in Temperate Fruit Crops

“…Freezing tolerance is an active trait, responsive to environmental fluctuations and it is genotype dependent for the timing of acclimation and dormancy, genetic potential for mid-winter freezing tolerance, rate of deacclimation, ability to reacclimate and timing of budbreak (Stushnoff, 1972). Therefore, winter survival is a multi-trait phenomenon that is impacted by photoperiod, temperature and water and nutritional status; all of which can interact differentially with genotype and tissue developmental stages (Fennell, 2004;Gusta and Wisniewski, 2012;Palonen and Buszard, 1997;Stushnoff 1972). Progress in selecting sustainable cultivars requires identifying critical phenotypes and susceptible tissues as well as critical environmental events (early fall freeze, mid-winter ultimate low temperature, deacclimation events).…”