The status of plum breeding around the world is reviewed. Two distinct types of plums are grown: Japanese-type shipping plums (mostly diploid hybrids of Prunus salicina Lindl. with other species) such as are grown in California, and hexaploid or “domestica” plums (P. domestica L.), which have a long history in Europe. In recent years there has been a resurgence of plum breeding outside the United States.
Twelve peach (Prunus persica) cultivars, six apricot (Prunus armeniaca) cultivars, two japanese plum (Prunus salicina) cultivars, three european plum (Prunus domestica) cultivars, four sweet cherry (Prunus avium) cultivars, and three tart cherry (Prunus cerasus) cultivars were monitored for winter damage at New Mexico State University's Sustainable Agriculture Science Center in Alcalde, NM (main site), and the Agricultural Science Center in Los Lunas, NM (minor site), in 2011. Uncharacteristically low temperatures on 1 Jan. and 3 Feb. were recorded as −7.2 and −11.3 °F, respectively, at Alcalde, and 4.8 and −13.9 °F, respectively, at Los Lunas. On 10 Jan. at Alcalde, live peach flower bud percentage varied by cultivar, ranging from 11% for Blazingstar to 25% for PF-1, and 85% to 87% for Encore and China Pearl. Apricot flower buds were hardier, with 70% survival for ‘Perfection’, 97% for ‘Sunglo’, and 99% for ‘Harglow’ on 10 Jan. By 10 Feb., almost all peach flower primordia were discolored, with no cultivar showing more than 1% survival. Based on this information, the 10% kill of flower buds for most peach cultivars occurred at temperatures equal to or slightly higher than −7.2 °F, and 90% kill occurred between −7.2 and −11.3 °F. On 10 Feb., 0% to 15% of apricot flower buds on spurs or shoots of the middle and lower canopy had survived. For vigorous shoots in the upper canopy, apricot flower buds on 1-year-old shoots had a higher blooming rate than those on spurs of 2-year-old or older wood. Flower buds of japanese plum were also severely damaged with less than 0.2% survival for ‘Santa Rosa’ and 4.8% for ‘Methley’, but european plum were relatively unaffected with over 98% flower bud survival for ‘Castleton’ and ‘NY6’, and 87% for ‘Stanley’ after −11.3 °F at Alcalde. Cherry—especially tart cherry—survived better than peach, apricot, and japanese plum after all winter freezes in 2011.
The influence of modified atmosphere packaging (MAP) on quality attributes and shelf life performance of ‘Friar’ plums (Prunus salicina) was studied. Plums were stored at 0 °C and 85% relative humidity for a 60-day period in five different box liners (LifeSpan L316, FF-602, FF-504, 2.0% vented area perforated, and Hefty liner) and untreated (control). Flesh firmness, soluble solids concentration, titratable acidity, and pH were unaffected by the box liners. Fruit skin color changes were repressed on plums packed in box liners that modified gas levels and weight loss was reduced by the use of any of the box liners. Plums packed without box liners (bulk-packed) had ≈6% weight loss. High carbon dioxide (CO2) and low oxygen (O2) levels were measured in boxes with MAP box liners (LifeSpan L316, FF-602, and FF-504). Percentage of healthy fruit was unaffected by any of the treatments during the ripening period (shelf life) after 45 days of cold storage. However, after 60 days of cold storage, fruit from the MAP box liners with higher CO2 and lower O2 levels had a higher incidence of chilling injury (CI) symptoms, evident as flesh translucency, gel breakdown, and “off flavor” than fruit from the other treatments. Overall, results indicate that the use of MAP box liners is recommended to improve market life of ‘Friar’ plums up to 45 days cold storage. However, the use of box liners without gas control capability may lead to CI symptoms in fruit cold-stored for longer periods.
Jujube, also called chinese date or red date, originated in China and has been cultivated for more than 4000 years ( Guo and Shan, 2010 ; Liu, 2006 ). Jujube together with peach ( Prunus persica ), plum ( Prunussalicina ), apricot ( Prunus
reported to increase fruit size in ‘Patharnakh’ japanese pear ( Gill et al., 2012 ), and the increase was greatest at a dose of 1.5% KNO 3 . A study of plum trees [ Prunussalicina ( Southwick et al., 1996 )] revealed that there was a correlation among the
Temperate fruit. Temperate fruit crops grown commercially in Florida include blueberry, stone fruit [(peach ( Prunus persica ), nectarine ( P. persica var. nectarina ), plum ( Prunussalicina )], muscadine grape, brambles (primarily blackberry
Automatic in-field fruit recognition techniques can be used to estimate fruit number, fruit size, fruit skin color, and yield in fruit crops. Fruit color and size represent two of the most important fruit quality parameters in stone fruit (Prunus sp.). This study aimed to evaluate the reliability of a commercial mobile platform, sensors, and artificial intelligence software system for fast estimates of fruit number, fruit size, and fruit skin color in peach (Prunus persica), nectarine (P. persica var. nucipersica), plum (Prunus salicina), and apricot (Prunus armeniaca), and to assess their spatial and temporal variability. An initial calibration was needed to obtain estimates of absolute fruit number per tree and a forecasted yield. However, the technology can also be used to produce fast relative density maps in stone fruit orchards. Fruit number prediction accuracy was ≥90% in all the crops and training systems under study. Overall, predictions of fruit number in two-dimensional training systems were slightly more accurate. Estimates of fruit diameter (FD) and color did not need an initial calibration. The FD predictions had percent standard errors <10% and root mean square error <5 mm under different training systems, row spacing, crops, and fruit position within the canopy. Hue angle, a color attribute previously associated with fruit maturity in peach and nectarine, was the color attribute that was best predicted by the mobile platform. A new color parameter—color development index (CDI), ranging from 0 to 1—was derived from hue angle. The adoption of CDI, which represents the color progression or distance from green, improved the interpretation of color measurements by end-users as opposed to hue angle and generated more robust color estimations in fruit that turn purple when ripe, such as dark plum. Spatial maps of fruit number, FD, and CDI obtained with the mobile platform can be used to inform orchard decisions such as thinning, pruning, spraying, and harvest timing. The importance and application of crop yield and fruit quality real-time assessments and forecasts are discussed.
categorizations, it was reported that some varieties of plum ( Prunussalicina ), apple ( Malus × domestica ), and pear ( Pyrus serotina ), exhibit a “suppressed-climacteric phenotype,” i.e., they produce ethylene during the later stages of ripening, but at lower