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Open access

M. H. Chaplin and M. N. Westwood

Abstract

A method for estimating sweet cherry yields was devised based on the calculation of a yield index value which incorporates estimates of the bearing surface of the tree and density of fruits on limb units. The relationship between yield index and actual yield was determined by regression analysis. The linear regression of yield index (Y) on actual yield (X) accounted for 84.6% of the variation.

Open access

M. H. Chaplin and M. N. Westwood

Abstract

The nutritional status of ‘Bartlett’ pear growing on P. communis seedling, Old Home × Farmingdale (OH×F), and several Pyrus species seedling rootstocks was compared to those growing on Bartlett seedling rootstock at 3 locations over a 2-3 year period. Few significant differences were found in leaf element content of scions growing on Bartlett seedling rootstock and those on the rootstock clones or other Pyrus seedlings. Nitrogen was higher in the scions on 5 of the OH×F rootstocks but did not seem related to yield efficiency. Generally the leaf element content of Mg and Mn was lower and Fe higher in leaves of trees growing on the OH×F clonal rootstocks when compared to trees on Bartlett seedling. Nutrient uptake and passage through graft unions appeared unrelated to the degree of graft compatability, based on the similarity of nutrient levels of ‘Bartlett’ scions grafted directly on quince rootstock and those with an Old Home interstem. Root system genetics seems to be the controlling factor of nutrient uptake rather than the interstock.

Open access

M. H. Chaplin and A. R. Dixon

Abstract

Nitrogen, as urea, was applied to filbert (Corylus avellena L.) trees at the rates of 0, .68, 1.36, and 2.72 kg N/tree/year from 1971-1977. Nitrogen applications significantly increased leaf N, yield, and tree size. Leaf P levels were reduced by N applications in all years. Soil pH, measured after 7 years of N application, significantly declined as N application rate increased. Leaf Mn levels were increased by N applications in all years, probably due to the decrease in soil pH. Yields were expressed as a quadratic function of N and the standard ranges for leaf N in filbert were categorized as follows: deficiency (visible symptoms present) < 2.0% dry weight; below normal 2.0 − 2.2%; normal 2.2 − 2.4%; above normal > 2.4%.

Open access

M. H. Chaplin and A. L. Kenworthy

Abstract

Field experiments were conducted in 1967 and 1968 to determine the influence of succinamic acid 2,2-dimethyl hydrazide (SADH) on fruit ripening of the ‘Windsor’ sweet cherry. Foliar sprays of 1000, 2000, or 4000 ppm of SADH were applied to mature ‘Windsor’ trees. SADH promoted anthocyanin development by two weeks and sugar development by one week without significantly reducing fruit firmness. Treated fruits, however, were smaller than non-treated fruits of comparable color and sugar content. Fruit respiratory activity was not affected by SADH treatment.

It is postulated that SADH acts directly on the enzyme systems concerned with anthocyanin and sugar biosynthesis rather than acting at the hormonal level to advance the general physiological maturity of the fruit.

Open access

M. A. Axford, M. N. Westwood, and M. H. Chaplin

Abstract

The nutrient content of rootstock and scion leaves from trees of ‘Napoleon’ and ‘Corum’ sweet cherry (Prunus avium L.) growing on Stockton Morello (Prunus cerasus L.) and East Mailing Mazzard F12-1 (Prunus avium L.) was analyzed. The concentration of Ca was greater in ‘Corum’ on F12-1 than on Stockton Morello. Rootstocks interacted with scions for K, P, Mg, Fe, Cu, B, and Zn.

Open access

M. H. Chaplin, M. N. Westwood, and A. N. Roberts

Abstract

Plantings of the ‘Italian’ prune (P. domestica L.) were established on seedling peach (P. persica L. Batsch) and clonal Myrobalan 29-C, B, 2-7 (P. cerasifera, Ehrh.); Marianna 4001, 2623, 2624 (P. cerasifera × Munsoniana?, Wight and Hedr.); and St. Julien A (P. insititia L. Bullace) rootstocks in 7 orchard sites in Oregon. Leaf samples were collected in the years 1968 to 1970 and analyzed for element content. Trees with plum rootstocks had greater leaf N, K, Mn, and Zn and slightly less B and Mg than those on peach. Plum clones, Myrobalan 29-C, Myrobalan B, and St. Julien A, were more efficient in the uptake of Ca. There were positive correlations between N and Ca, N and Mg, N and B, N and Zn, Ca and Mg, Ca and B, and Mg and B for most of the stocks. There was a negative correlation between K and Mg for Myrobalan 2-7 and the 3 Marianna clones. Myrobalan B and Marianna 2623 and 2624 had a negative corrleation for K and Ca whereas St. Julien A had a positive correlation.

Open access

M. H. Chaplin, R. L. Stebbins, and M. N. Westwood

Abstract

Boron sprays applied in the fall to ‘Italian’ prune trees (Prunus domestica L.) not deficient in boron resulted in a significant increase in fruit set and yield the following year. Analysis of midshoot leaf tissue the August following treatment showed no differences in boron content. These data indicate a possible transitory need for boron during the floral development and fruit set processes in ‘Italian’ prune which cannot be diagnosed by traditional leaf analysis.

Open access

Nancy W. Callan, Maxine M. Thompson, M. H. Chaplin, R. L. Stebbins, and M. N. Westwood

Abstract

A pre- or postharvest foliar B application was found to increase fruit set of ‘Italian’ prune (Prunus domestica L.). A prebloom B spray failed to increase set. Neither fall nor spring applications influenced the amount of fruit lost in the midsummer or “blue” drop. All trees involved in the experiment had adequate B by the standard index of tree nutrition, August mid-shoot leaf analysis. Incipient B deficiency did not appear to be involved.

Fall foliar B increased B levels in dormant bud and spur tissues and in flower buds and flowers. A prebloom B spray increased B levels of floral tissues to a lesser degree. The highest B concentration was found in the ovary. Boron concentration in flower buds in April following a fall B spray was as much as five times the amount found in mid-shoot leaves in August. August mid-shoot leaf analysis revealed higher levels in leaves from trees treated the previous fall in only one of the 2 years.

Several morphological and physiological effects of the fall B spray were observed. Among these were a slight delay in the time of bud break, a decrease in the size of flower buds and mature flowers accompanied by reduction of style and pedicel length, and a decrease in pollen germinability. B level of pistil and pollen had no effect on in vivo pollen tube growth rate.

Open access

M. N. Westwood, M. H. Chaplin, and A. N. Roberts

Abstract

Tests in 11 plots of ‘Italian’, ‘Early Italian’, and ‘Brooks’ prunes showed several influences of rootstock on tree growth, flowering, yield, fruit size, maturity, and quality. Of the 6 Prunus species represented by the 19 rootstocks tested, myrobalan roots usually resulted in larger trees, heavier bloom, but lower yield efficiency than did peach roots. Trees on Marianna and several P. domestica L. roots varied in size and yield, but most of them had greater bloom density than trees on peach root. ‘Italian’ fruit firmness varied inconsistently with rootstock. ‘Early Italian’ fruits were firmer on peach than on other roots, but ‘Brooks’ fruits were less firm on peach than on other roots. The tendency for internal fruit browning of ‘Italian’ was greater on plums than on peach roots. Other fruit maturity and quality factors varied by cultivar and by individual rootstock. Fewer trees on peach root died from trunk canker (Pseudomonas syringae van Hall) than did those on several clonal plum roots, but some plum-rooted trees outgrew the canker and survived as well as trees on peach stock.

Open access

E. J. Hanson, M. H. Chaplin, and P. J. Breen

Abstract

To study the distribution of foliar applied B in ‘Italian’ prune (Prunus domestica L.) trees, 500 ppm B solutions were applied in July, September, and October. Boron applied in September or October moved readily out of senescing leaves and apparently into adjacent flower buds and subtending tissues. Boron applied in mid summer (29 July) moved out of nonsenescing leaves at a similar rate. Flower buds accumulated B slowly in the fall and winter, but rapidly during bud swelling. In flowers, the largest increases in B concentrations due to foliar sprays were in anthers (248%) and styles (162%).