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- Author or Editor: Arthur H. Thompson x
Abstract
Seventy-five years ago U.S. pomology was caught up in a ferment which marks the ebb and flow of any great agricultural industry. The beginnings of great things to come were in sight, though perhaps unrecognized as such, while the end of other eras was at hand. San Jose scale was being conquered, while peach yellows had destroyed the vast peach industry which bordered the Chesapeake Bay, an industry which made Maryland the leading peach state for a while. The demise of the peach industry was followed shortly by runaway plantings of apples from the mountains of Appalachia westward to Ohio; curiously a similar overexpansion developed in Washington and Oregon as well at that time. South Carolina was just beginning to plant peaches, and it would be 20 years before Michigan would commence peach breeding at South Haven. New Jersey had supported orchard fertilization experiments for 20 years, other Northeastern states for nearly as long. Cultivars were called varieties, and there were great numbers of them in all commercial deciduous fruit orchards. The leading apple cultivar by far was ‘Ben Davis’, but Stark Bros. Nursery had owned Jesse Hiatt's apple for 10 years, and was well under way toward making the 20th century, the ‘Delicious’ century in American apple production. The first high density apple orchard was already 8 years old, this a planting of ‘Wealthy’ trees on seedling rootstocks, spaced 10 × 10 feet, at the Central Experimental Farm in Ottawa, Ontario. But this planting was an idea well ahead of its time, for more than 60 years would pass before the term “high density” would have any meaning in American or Canadian pomology.
Abstract
Manganese toxicity was expressed as leaf chlorosis, early leaf abscission, reduced flower bud number, reduced growth, and internal bark necrosis (IBN). Increasing Ca or decreasing Mn in the solution were effective in correcting IBN, while increasing B or pH were ineffective. High solution Mn was associated with a decrease in bark Ca, and high solution Ca was associated with decreased Mn accumulation. Severe IBN was observed on the ‘Delicious’ scion, but no bark symptoms were visible on the EM IX clonal stock. Manganese concn were similar in both stock and scion bark, but Ca levels in the stock bark were substantially higher than those in the scion.
`Gala' apples are increasing in worldwide popularity. Despite this, little information on the cultivars vigor, precocity, or interaction with size-controlling rootstock is available. In 1985, a factorial planting was set to study these variables. `Gala' and `Golden Delicious' trees were found similar in precocity. Cumulative yields were about 20 kg per tree after the fifth leaf. `McIntosh' and `Delicious' trees were less precocious. `Gala' trees were also quite vigorous. Tree size and yield efficiency data will be presented, comparing `Gala' with other cultivars budded onto M 7a, MM 111, or propagated in tissue culture as scion-rooted plants. Tree management techniques have been identified that decrease fruit size. Trees budded onto precocious rootstock, and fruited heavily on one-year wood produce small-sized fruit. This tendency is pronounced on trees fruiting in the second leaf, or on older trees damaged by late-spring freezes that reduce the proportion of crop borne on spurs.
Abstract
‘Redskin’ peach (Prunus persica Batsch.) trees, planted at a high-density spacing (3 × 5 m), were fertilized annually with urea at rates of 45, 90, or 135 kg·ha−1. Trees were trained to a trapezoidal hedge by annual, mechanized, summer pruning. Within each fertilizer plot, subplots of five summer-pruning treatments were applied. Single pruning treatments were made at 120 days after full bloom (DAFB) and 150 DAFB. Paired pruning treatments were applied 30 + 60 DAFB, 60 + 120 DAFB, and 60 + 150 DAFB. Pruning at 120 DAFB alone, and in combination with pruning at 60 DAFB, decreased trunk cross-sectional area (TCA), fruit soluble solids content, and weight, while increasing the percentage of surface that was red. Pruning at 30 DAFB followed by a second pruning at 60 DAFB decreased leaf Ca concentration in comparison to pruning treatments applied later in the season. Increasing N fertilization also decreased leaf Ca. Year, N level, and pruning treatments gave a statistical interaction on mean fruit weight and yield.