• Abstract and Figures
• Public Full-text

they are grown south of Lodi. The produc- tion of abnormal fruit from a given or- Over4ree spr in kl i ng reduces chard may be a consequence of high canopy temperatures affecting flower bud abnormal shapes in 'Bing' development during the previous year. Canopy temperature can be modified di- rectly by over-tree sprinkler irrigation, but sweet cherries can also be modified indirectly by irriga- tion practices which influence evaporative cooling from the leaves. Stephen M. Southwick o Kenneth A. Shackel D James T. Yeager Our goal in these and other studies has Wesley K. Asai o Matt Katacich, Jr. been to quanbfy the problem of abnormal fruit production in 'Bing' sweet cherry in and among various growing districts, and to identify important environmental fac- The 'Bing' sweet cherry produces higher night temperatures. The fact that tors contributing to this problem. This increased numbers of abnormal early maturing sweet cherries attract study sought to determine whether cul- fruit shapes when grown in cetfain strong prices, coupled with the fact that tural practices which were designed to in- many San Joaquin County trees are dis- fluence canopy temperatures, such as regions in California,rendering the eased and dying, has led to increased over-tree sprinkling or irrigation method, fruit less marketable.Postharvest planting of sweet cherries in warmer, non- could economically reduce abnormal fruit under- and over-tree sprinkler irri- traditional sites of Stanislaus, Merced, production. Fresno, Tulare, Kings and Kern Counties. gation led to a reduction in the pro- Treatments,experimental design duction of abnormal fruit shapes in- Stanislaus County has especially seen many of the new commercial 'Bing' In 1988, we selected a 200-acre orchard dicating that canopy climate plantings. These sites have warmer spring located on the west side of Patterson modificationmay be an alternative temperatures with earlier floweringand where many abnormal and sutured 'Bing' to growers producing 'Bing'cher- fruit maturation. Postharvest summer cherry fruit had been observed. Patterson ries in those regions where these temperatures, however, are also high, and itself is located on the eastern slope of the abnormal fruit shapes are prevalent. evidence suggests that the production of coast range. We identified southern and abnormal fruit from a given orchard may northern locations within that orchard be partly due to high canopy temperatures based on the grower's observation of a during the previous year. consistent difference in the percentage of 'Bing' sweet cherry is the leading cherry Crinkle leaf, deep suture and variega- abnormal fruit found from the two loca- cultivar in California and the Western U.S. tion are recogruzed genetic disorders of tions over the years. Trees in both loca- It was selected in Oregon from the seed of both 'Bing' and 'Black Tartarian'. The tions growing on Prunus mahaleb the 'Republican' cultivar in 1875. The culti- crinkle leaf disorder occurs in nursery rootstocks were arranged into randomized var rose to prominence because of its size, stock and bearing trees and is perpetuated complete block designs consisting of nine taste, firmness and degree of shipability. through propagation. Affected nursery trees per plot. Two irrigation treatments, Commercial sweet cherry (Prunus aviurn) trees are usually rogued out before sale. drip and mini-sprinkler, consisting of four production in California, (which includes Crinkle leaf and deep suture disorders can replicates each and separated by at least 'Bing' and other cultivars) has been local- be found on mature bearing trees in spite three guard trees in both directions (20 x ized in regions where climate is moder- of the fact that they were symptomless 20 foot spacing)were established in the ated by ocean or elevation, and where pro- when planted. Branches on trees affected southern location. Drip-irrigated trees longed periods of high temperature by crinkle leaf are less productive and the were supplied with water from five emit- (greater than 95OF) are less common than fruit may have abnormal shapes. Deep su- ters which delivered one gal/hr. Mini- on valley floors. Grower experience has ture is bud-perpetuated like crinkle leaf, sprinkler irrigated trees were supplied shown that higher quality cherries are pro- but limbs showing leaf symptoms of deep with water by Dan emitters (Netafim Irri- duced in sites with more moderate tem- suture also have fruit with an indented or gation, Inc.) which delivered 11 gal/hr. peratures. - depressed ventral suture (see photos on p. Emitters were placed at every space be- The California sweet cherry industry is 25). In some of the worst cases, the fruit tween trees in a row. Consequently, the localized on approximately 8,000 acres in may have indented suture lines extending pattern and amount of water delivered to San Joaquin County. Additional acreage is to the stone. These fruit are referred to as trees of each irrigation treatment varied. located in Stanislaus, Contra Costa, San "sutured". There is a minimum tolerance Seasonal irrigation began approxi- Benito, Santa Clara, El Dorado, and Sacra- set by the state inspection service for the mately April 1 and finished September 1 mento Counties, among others. Histori- length of the suture (3/8 inch), beyond with each tree receiving approximately 48 cally the market for sweet cherries has which the fruit becomes much less valu- hr of water per week. A mini-sprinkler been relatively strong and the recent ad- able and cannot be shipped as a U.S #l. and a mini-sprinkler plus over-tree irriga vent of a fresh sweet cherry market in Ja- As more 'Bing' cherries have come into tion treatment were established in the pan has helped to strengthen demand. bearing age, especially in regions south of northern location, each replicated six 'Bing' is identified as a superior culti- Lodi in the San Joaquin Valley, the pro- times. Over-tree sprinkling was applied to var in cherry marketing. In general, the duction of sutured fruit has become more individual trees beginning the first week earlier the fruit matures in the season the pronounced. However, leaf symptoms of July by a single 11 gal/hr mini-sprinkla higher the price received. Consequently, normally associated with fruit suturing which was supported by an 8-meter tall growers are looking for ways to mature are not always found. Other abnormal steel pipe connected to the under-tree irri- 'Bing' cherries as early in the season as fruit shapes (eg. fruit "doubles" or gation system. The combined over-tree possible. Fruit maturity can be advanced aborted secondary fruit "spurs" shown on sprinkler and under-tree irrigation system by warmer temperatures, especially p. 25) are also seen in 'Bing' cherry when was turned on during irrigation, and on 24 CALIFORNIA AGRICULTURE, VOLUME 45, NUMBER 4 non-irrigation days when the ambient air Above left are normal ‘Bing’cherry leaves (I.) temperature exceeded approximately compared to leaves with crinkle symptoms (r.). 95°F; the system was turned off at dusk. Above right are normal ‘Bing’ cherries (I.), Hence, trees treated by over-tree sprin- compared with sutured fruit (r.). klers received somewhat more water as a Photo at right shows ‘Bing’ cherries exhibiting function of the overhead irrigation (3 to 5 “double”and “spur”characteristics. Below, su- days per week and 3 to 5 hr per day on av- tured ‘Bing’ cherries which do not meet US. #1 erage) than were trees irrigated only with grade standards. mini-sprinkler under-tree irrigation. For comparison, other orchard sites were evaluated for the production of fruit with abnormal shapes. These included Hollister, situated in the southern end of the Santa Clara Valley and influenced by coastal breezes, and Stockton and Lodi, situated in the Central Valley and influ- enced by delta breezes. Six individual tree replicates were selected at those sites. From each replicate tree at every orchard location, 25 fruit were collected from south eas experiencing high summer tempera- cated in the southern location of Patterson top, north top, south bottom and north tures produce less normal fruit. Of the ab- in 1989, one-half of the drip irrigated trees bottom canopy positions. Using the same normal fruit produced, sutured fruit were were switched to over-tree sprinkled in sampling technique, fruit were collected most prevalent followed by spurred and 1989 and evaluated in 1990. That treat- from two central trees in each nine-tree doubled fruit in both years. ment reduced the production of sutured plot at Patterson and a single tree in or- Within the Patterson northern location, fruit by 30% and increased the production chards from other locations. Fruit were the over-tree sprinkling treatment sub- of normal fruit within the southern loca- classified into categories of normal (U.S. stantially reduced sutured fruit produc- tion of Patterson by 30% (table 2). There #l),sutured, spurred or doubled. Trees tion by 27% and increased the production was also a small but not statistically sig- utilized in these experiments were at least of normal fruit by roughly 21 % in 1989. nificant effect of over-tree sprinkling on 9 years old and planted at distances of at Canopy temperatures measured with wire increasing normal fruit production in the least 20 x 20 feet. All percentage data were thermocouples were reduced as a function northern location in 1990. transformed using the arc sine of the of over-tree sprinkling in 1988 (data not Exposed positions in tree canopies square root before analysis and values shown). (south and north tree tops) led to the pro- were rounded to the nearest sigruficant Since there was no difference between duction of more spurred and doubled fruit digit. Analyses of variance (ANOVA) and drip and mini-sprinkler irrigated trees lo- and fewer normal fruit than lower canopy Duncan’s multiple range tests were car- ried out by using Statistical balyses Sys- TABLE 1.

Load more

  3

Copy Link