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  • Author or Editor: D. O. Ketchie x
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A two-year study was conducted on 12 possible varieties as pollen sources for Anjou pear. Bloom dates of the varieties were compared with bloom date of Anjou. Viability of pollen was determined including germination and tube growth. The Anjou trees were hand-pollinated using the various sources of pollen, then later we determined fruit set. The fruit was harvested and size of fruit, number of seeds, firmness, soluble solids, titratable acidity and physiological disorders were determined. Bloom dates corresponding most closely to Anjou were Bartlett, Pyrus calleryana and the Asian pear Nijisecki. Pollen from El Dorado, OHxF 33 and OHxF69 had the highest percent germination and the best pollen tube growth. Bartlett, Pyrus calleryana, Nijisecki, OHxF333 and OHxF69 showed the highest percent fruit set. The largest fruit was from flowers pollinated with Nijisecki, Dawn, Bose and self-pollinated. Fruit with highest numbers of seeds was fruit with pollen from Nijisecki, Usserienses, Dawn, Comice and Bosc. There was no difference in firmness, soluble solids or tritratable acidity, and there was no physiological disorders. The study indicated Bartlett pear is the best all-round pollinizer for Anjou pear.

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Five different pruning techniques were begun in 1990 on Anjou pear trees to determine their effect on fruit set: (1) unpruned; (2) central leader, (3) central leader modified to Verner method; (4) stubbed into 2- to 4-year-old wood first year and then developed to central leader; and (5) mold-and-hold. Half of each treatment was spread, the other half not spread. Half of each of the combination training and spreading were tipped back to the first fruit bud at cluster bud time. The trees were 9 years old and on OHXF97 rootstock. The unpruned trees had the highest yield, 81 Kgm/tree. The other treatments ranged between 52 and 58 Kgm/tree. Regardless of pruning treatment, the spread trees out yielded the non-spread trees by 16 Kgm/uee.. There was essentially no difference between trees tipped in the spring and those that were not tipped.

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In the past, the laborious and time-consuming method of defoliation was used to determine vegetative maturity (VM) of various deciduous plants. Other methods such as water potential and electrotrical impedence have been explored without a positive response. A change of freezing events of water in plant tissue may be associated with VM. Differential thermal analysis (DTA) was tried to determine if the freezing events of water are related to VM. `Golden Delicious', `Gala', `Red Fuji' and `Antonovka' apple (Malus domestica Borkh.) trees were used to determine VM by defoliation. Different sets of 1-year-old trees grown in pots in the greenhouse were defoliated weekly from 1 Aug. until it was assured the trees had reached VM. Samples from the same trees were taken for DTA. The trees were observed for regrowth 2 weeks after they were defoliated, and the exothermic patterns from DTA were examined for the appearance of an exotherm at about –35 to –40°C. The comparison of regrowth from trees defoliated from a specific date were compared to the exothermic pattern of the same date. An exotherm appeared between –35 and –40°C ≈2 weeks before the apple trees ceased to show regrowth from the defoliation treatment. The exotherm appeared on 30 Aug. for Antonovka and `Golden Delicious' and regrowth of the trees ceased on 12 Sept. Regrowth ceased on 9 Oct. for `Gala' and `Fuji' preceded by the exotherm on 2 Oct. The conclusion was that the appearance of the exotherm at –35 to –40 °C could be used to determine VM.

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Abstract

In ‘Delicious’ apple (Malus domestica Borkh.) trees affected by dead spur disorder (DS) no over-all deficiency was in N, P, K, Ca, amino acids, proteins, sugars or phenols as compared with healthy (CK) trees. N, amino acid and protein contents were higher in DS than in CK spurs on 1- and 2-yearold limb sections. Relatively low nutrient levels in DS spurs on 3-4-year old limb sections indicated that translocation of nutrients to these spurs was restricted. Phenol contents were lower in DS than in CK spurs. P and K contents were higher in DS than in CK spur leaves.

Open Access

Abstract

Pink phloem was found during the winter months in all spurs on ‘Delicious’ apple (Malus domestica Borkh.) trees affected by dead spur disorder and was less frequent the remainder of the year. On healthy trees pink phloem was found in young spurs, but seldom at the base of older spurs. The pigment was identified as the anthocyanin cyanidin-3-galactoside.

Open Access

Abstract

A method is described for introducing small quantities of chemicals by gravity flow into terminal shoots of young apple trees. The destruction of acid fuchsin and 14C labelled growth regulators by this method was down the main stem, out to the lateral branches, and into the leaves.

Open Access

Abstract

Limb units and whole trees of ‘Delicious’ and ‘Golden Delicious’ sprayed in the fall with 250 ppm, 500 ppm and 1000 ppm Ethrel significantly decreased fruit set and vegetative growth the following season.

Open Access

Yield components of spur and non-spur strains of `Delicious' apple, on 2 rootstocks were compared over 4 years (5th through 8th leaf). Yield per unit trunk cross-sectional area was higher in spurs than in non-spurs with but few exceptions. Differences in fruit set, rather than in flower density or fruit size, were largely responsible for this difference in yield. Yields were higher on EMLA 7 than EMLA 111 rootstock, partially because of earlier bearing. When cropload was factored out, fruit size was slightly greater on EMLA 7 than on EMLA 111.

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Abstract

“Dead spur” is a disorder which affects the spurs of ‘Delicious’ apple (Malus domestica Borkh.). The spurs die on 2-year-old and older sections of the tree. A survey of ‘Delicious’ sports showed Royal Red, Earlistripe and Sharp have a higher incidence of dead spur than the other sports. There was no relationship of the disorder to rootstock, but the interstock Ottawa 292 increased the severity of dead spur.

Open Access