Abstract
An 8-year study was made to assess the performance of Harrow Blood and Siberian C rootstock seedlings in comparison with the commercial seedling rootstocks Rutgers Red Leaf, Veteran, Halford and Bailey. Rootstocks significantly influenced tree size of ‘Loring’, ‘Redhaven’ and ‘Babygold 5’ peach (Prunus persica (L.) Batsch). Siberian C had the largest influence on size control, reducing tree volume by about 20%. Tree height and spread, trunk circumference and trunk cross-sectional areas were also influenced by rootstocks, but annual growth of terminal shoots was not. Rootstocks influenced crotch angle development of ‘Loring’, but had no effect on crotch angle development of ‘Redhaven’ or ‘Babygold 5’. Cropping efficiency of ‘Babygold 5’ was influenced by rootstocks but cropping efficiency of ‘Redhaven’ and ‘Loring’ were not. Yields were significantly influenced by rootstocks. The highest cumulative yields of ‘Loring’ were on Veteran seedlings, the highest of ‘Redhaven’ were on Rutgers Red Leaf and the highest of ‘Babygold 5’ were on Halford. Yields were also a function of tree size with the highest yields being obtained on the largest trees. Trunk circumference and crosssectional area were the only growth measurements that were significantly correlated with the yield of each cultivar. Tree survival was best on Harrow Blood and Siberian C and poorest on Rutgers Red Leaf and Veteran. Tree mortality was associated with winter injury and canker (Leucostoma spp.) infection but not with incompatibility.
Abstract
An experimental peach (Prunus persica [L.] Batsch cv. Harken/Siberian C) orchard was planted on Fox sand in 1973 at 266, 358 and 536 trees/ha. The plots were either not irrigated or irrigated at a frequency necessary to prevent the available soil moisture (ASM) from falling below 25 or 50%. Irrigation stimulated tree growth in the earlier but not in the later years of the experiment. Growth was reduced by an increase in tree density especially in the later years at the highest density. Only in 50% ASM plots was growth not affected by high tree density. Irrigation (50% ASM) increased cumulative, marketable yields in the first 5 years of production by up to 9.7% while tree density (536 trees/ha) increased similar yields by up to 74.6% without irrigation and up to 99.5% with irrigation (50% ASM + 536 tree/ha). Irrigation consistently improved the proportion of large and medium-sized fruit while reducing the proportion of small, unmarketable fruit. Tree density had a smaller and less consistent influence on fruit size. Neither irrigation nor tree density adversely affected split pits, raw product fruit quality, cold hardiness or canker (Leucostoma spp.) susceptiblity. There were no significant interactions of irrigation and density treatments in any year, indicating that each treatment might be used to advantage without adversely affecting the other, at least in the first 7 years of growth and first 5 years of production.
Despite the hundreds of existing stone fruit (Prunus spp.) cultivars used for fresh market, there is a continuing need to develop new stone fruit cultivars as the requirements of the industry change. Over the last 20 years there has been a shift toward private breeding as the public sector decreases its support of these long-range programs. As a result there are fewer public breeding programs and many of those still operating protect their releases and partially fund their programs with royalty payments. Other trends that are shaping the development of new stone fruit cultivars are a need for smaller or more easily managed tree architecture, a trend toward the use of fewer agricultural chemicals, the expansion of production zones into the milder winter zones to allow year-round availability of stone fruit, a general diversification of fruit types being marketed, the increased awareness of the health benefits of fruit consumption, the need for better and more consistent quality, and given the global marketing of these fruit the increased need for enhanced postharvest qualities. The breeding programs of the world are responding to these trends and working toward developing the cultivars for the world markets of the future.
The genus Prunus comprises five subgenera: Prunus , Amygdalus , Cerasus , Padus , and Laurocerasus and includes ≈200 species, which are economically important as sources of fruits, nuts, oil, timber, and ornamentals ( Reynders and Salesses
evaluate the response of 12 Prunus genotypes in the first few years to A. solidipes , A. mellea , and D. tabescens , and to determine their active and passive responses to Armillaria spp. infection. Specifically, this study seeks to characterize the
the total chloroplast genome (considering that cpDNA size in most Prunus spp. is ≈140 kbp ( Kaneko et al., 1986 ; Uematsu et al., 1991 ). No length polymorphisms were detected in the obtained PCR products using any of the primer pairs tested
report, EHA105 appeared to give the greatest rate of gene delivery in peach epicotyl internodes, cotyledons, leaves, and embryonic axes ( Padilla et al., 2006 ). To date, EHA105 has been used for a successful transformation of several other Prunus spp
genotypes ( Prunus cerasifera Ehr.) highly resistant to Meloidogyne spp Fundam. Appl. Nematol. 19 85 90 Esmenjaud, D. Minot, J.C. Voisin, R. Pinochet, J. Simard, M.H. Salesses, G. 1997 Differential response to root-knot nematodes in Prunus species and
Logs of white and red oak (Quercus spp.), black cherry [Prunus serotina (Ehrh.)], sassafras (Sassafras albidum (Nutt.) Nees), and eastern sycamore [Platanus occidentalis (L.)] were inoculated with eight strains of shiitake mushroom in 12-mm holes drilled 25 mm deep and spaced 15 cm apart down the log and 5 cm apart around the log in a staggered pattern. Logs then were placed in quonset houses covered with 80% shadecloth in Mar. 1991. The environment within these shaded houses was not modified otherwise. Harvested mushrooms were counted and weighed and biological efficiency (BE) was determined. White and red oaks produced significantly higher yields of shiitake mushrooms over the lifetime of the log than the other types of wood. Only one strain, CW25, produced significantly lower yields than the best four strains. Interactions among strains and seasons of harvest and the species and seasons of harvest were significant. The most productive mushroom strains and tree species yielded more mushrooms later in the life of the logs than the least productive strains and tree species did earlier in the life of the logs. BE attained from strain × species interactions ranged from 0% (WW70, CW25, and WR85 on sycamore) to 8.8% (WW44 on red oak) in an outdoor noncontrolled environment. The gross per cord value (at wholesale price) of shiitake harvested from white oak was $2475.00. The cost of producing one cord of shiitake is about $6.44 per log in a small-scale operation. A net return of $1509.00 per cord is realistic and includes the cost of labor.
Bacterial canker (BC), caused by Pseudomonas syringae pv. syringae van Hall, is a serious disease of stone fruits that occurs most commonly in young orchards. Many factors can predispose or increase the risk that trees develop BC such as sandy or compacted soils, low soil pH, inadequate tree nutrition, frost or cold injury, genetic susceptibility, and presence of ring nematode, Criconemella spp. However, questions still remain about how these factors influence disease incidence in `French' prune, Prunus domestica L. In 1991, we established a 3.64-ha plot in Winters, Calif., to determine the effects of nitrogen (N) fertigation on growth responses and yield of young prune trees. N was applied through a surface drip system at 0, 0.11, 0.23, and 0.45 kg actual N/tree per year as UN32 urea (Unocal, Sacramento Calif.) with 1/10th of the total amount delivered per application every other week from May through September starting in 1992. Two other treatments were also included: 0.064 kg N/tree per year through surface drip if % leaf N dropped below 2.3%, and 0.23 kg N/tree/year delivered in small amounts every irrigation via an automated buried drip system. Symptoms of BC began appearing primarily in the 0- and 0.064-N treatments in 1993. During 1995 and 1996, we demonstrated highly significant relationships between low N status measured in leaves and increased incidence of BC. Furthermore, we determined levels of N application via drip irrigation, which resulted in good yields, vigorous growth, and lack of BC in our test plots, but also minimized N use and potential for nitrate leaching into groundwater. These and additional results will be presented.