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  • Author or Editor: H. R. Cameron x
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Abstract

It is now generally accepted that virus, or virus-like, diseases are common in many of our fruit crops. Only 5 virus diseases of stone fruits were known in 1930 (22), 48 were reported in 1951 (1) and 95 in 1976 (2). For many of these diseases the causal agent has not been identified, but because the disease is graft transmissible, and no visible organism can be found, the disease is attributed to a virus. Since 1968, some of these diseases have been shown to be associated with mycoplasmalike bodies, spiroplasmas, and viroids. Probably other types of infectious agents will be found in the future. However for the purposes of this paper, all of these causal agents will be considered in the general grouping of virus-like entities.

Open Access

Abstract

High proportions of 3x hybrids were obtained from crosses of 4x highly sexual seed parents by 2x pollen parents in Citrus. This is in contrast to the low proportions usually obtained with 4x partly apomictic cultivars as seed parents, or with 4x plants used as pollen parents. Initial survival of small germinating seeds and very young seedlings was low but later growth vigor has been high. Ten 4x and 9 aneuploid (near 3x) plants were identified.

Open Access

Abstract

The occurrence of solution pockets in brined sweet cherries has increased during the past 15 years. Affected fruits exhibit translucent pockets beneath the epidermis, filled with ruptured cell contents and brine solution. Pockets may occur anywhere in the fruit but are commonly at the suture. Affected fruits sometimes are not firm enough to pass through a pitting machine without being torn, increasing cullage and lowering grade. Sweet cherries are brined in a solution of sulfur dioxide and lime rather than the usual salt-brine method used on other crops (4).

Open Access

Abstract

Growth and performance of ‘Anjou’ pear, Pyrus communis L., were reduced by infection with severe vein yellows virus (VYV) tested in 2 plots for 10 years. Bloom density and yield with some selections were reduced by the virus. Overall performance was affected by scion source as well as by VYV content. Inconsistencies resulted apparently from either undetected viruses, different strains of VYV, or from differences in genetic strains of the pear cultivar.

Open Access

Abstract

Pear plots established in 1923 and 1926 with trees composed of several rootstock and trunk combinations were assessed for tree size, susceptibility to pear decline and for fruit quality. In general, Pyrus ussuriensis Max. and P. pyrifolia Burm. & Nak. rootstocks resulted in small trees, P. communis L. and P. calleryana Decne. intermediate, and P. betulaefolia Bunge large. The latter was most resistant to decline, followed by P. calleryana and P. communis, with P. pyrifolia and P. ussuriensis susceptible. The use of the oriental hybrid cvs. Variolosa and Tolstoy as interstocks increased the severity of pear decline symptoms though all trees were not uniformly susceptible. The use of the P. communis cv. Old Home as a scion rooted trunkstock decreased the degree of decline. Fruit quality was good on most combinations but was generally better on P. calleryana than other rootstocks. Pyrus betulaefolia caused cork spot and poor quality of ‘Anjou’ but this same rootstock resulted in outstanding quality of ‘Seckel’.

Open Access