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Stephen S. Miller

To control excessive growth, vigorous `Smoothee Golden Delicious', `Jonagold', `Empire', and `Gala' apple (Malus domestica Borkh.) cultivars on Malling 7A (M.7A) rootstock planted at close in-row spacing (2.5 or 1.8 m) were mechanically root-pruned (RP), trunk-scored (TS; ringing), or both, annually for 3 to 5 years beginning in the fourth leaf. Trees were grown in a deep, well-drained, fertile soil and supplied with trickle irrigation. RP reduced terminal shoot length in 2 of 5 years on `Smoothee Golden Delicious'; trunk cross-sectional area (TCSA) was not affected by RP. TS reduced terminal length in 3 years and TCSA in each of 5 years of treatment on `Smoothee Golden Delicious'. Bloom density was not affected by RP on `Smoothee Golden Delicious' but was increased by TS in two of the three years measured. RP reduced terminal shoot length in `Gala', `Empire', and `Jonagold' in most years and TCSA in 1993 for all cultivars. TS had no effect on shoot length or TCSA in these three cultivars. Effects of RP and TS on yield and fruit size varied with year and cultivar. In general, the effects of RP and TS were inconsistent and often failed to reduce shoot growth or canopy spread. No practical advantage was recognized from these techniques for young apple trees growing on a fertile site with trickle irrigation.

Full access

Stephen S. Miller

The ‘Stayman’ apple (Malus ×domestica) is a high-quality apple with good fresh-fruit and processing characteristics. Trees are of moderate to high vigor where it is grown in large numbers in the mid-Atlantic region of the United States. However, ‘Stayman’ is prone to skin cracking, which in some seasons can result in losses that exceed 60% to 80% of the crop. A series of experiments was conducted between 1997 and 2001 to examine the effect of prohexadione–calcium (PCa) and a mixture of gibberellins A4 plus A7 (GA4+7) on shoot growth and cracking in ‘Stayman 201’ apple. PCa consistently reduced terminal shoot growth when applied in two or three sprays between petal fall (PF) and PF + 6 weeks [May and June (postbloom)]. PCa applied postbloom combined with three or four preharvest (July and August) PCa applications reduced the growth of water sprouts. The level of ‘Stayman’ fruit cracking varied with year, but in three of five experiments conducted from 1997 through 2001, five biweekly GA4+7 sprays applied alone preharvest reduced the percentage of cracked fruit at harvest. With only a few exceptions, spraying with PCa increased fruit cracking. When GA4+7 was applied to trees previously treated postbloom with PCa, the percentage of cracked fruit was often reduced, but not always, and generally not to the same level as that in non-PCa-treated trees. Fruit cracking was increased compared with the untreated control when a spray adjuvant was included with the postbloom PCa spray. PCa or GA4+7 had no effect on yield or fruit weight at harvest. The results of this study suggest caution in the use of PCa to suppress shoot growth in bearing ‘Stayman’ apple trees because of the potential for increased fruit cracking, which may be only partially reversed by the application of GA4+7.

Open access

Stephen S. Miller

Abstract

Two-year-old peach trees [Prunus persica (L.) Batsch cv. Candor] on ‘Lovell’ rootstock were summer-pruned (selective thinning and heading of current season's growth) 23 days before harvest. Pruning did not affect fruit quality. Summer pruning increased yield the subsequent year, apparently by increasing fruiting wood in the center of the tree. Summer pruning vigorous 3-year-old ‘Loring’ peach trees 8 weeks before harvest increased PAR through the canopy, 1 m above the ground, immediately after pruning and when measured at harvest. Fruit from summer-pruned ‘Loring’ were firmer, with lower soluble solids than those not summer-pruned.

Open access

Stephen S. Miller

Abstract

Low volume (concentrate) sprays to 7.5X (375 liters/ha) of BA applied at fixed rates (137 and 228 g/ha) with airblast equipment were as effective as full dilute applications (2800 liters/ha) for inducing branch development on young apple (Malus domestica Borkh.) trees. Sprays of BA or BA + gibberellin A4+7 (Promalin) applied in a spray solution based on tree-row-volume increased branching significantly at IX but failed to produce a response when applied as a concentrate spray at a fixed chemical rate. Cultivars responded similarly to changes in spray volume.

Open access

Stephen S. Miller

Abstract

Vigorous, young trees of ‘Topred Delicious’ apple (Malus domestica Borkh.) either dormant-pruned or left unpruned at the end of the previous season, were summer-pruned at 8, 12, 16, or 20 weeks after full bloom (WAFB) by thinning, heading, or stubbling current season to 2-year-old shoots. The amount of new growth following summer pruning (regrowth) was influenced by the date of pruning; late pruning (20 WAFB) generally produced less regrowth than earlier pruning (8 WAFB). Regrowth also varied with moisture conditions during 2 growing seasons. Severe heading or stubbing of vigorous vegetative shoots to 2 or 3 nodes resulted in flower bud initiation on some spurs produced from axillary buds on these stubs. The degree of fruit bud initiation was related to time of pruning and moisture supply. Summer pruning generally increased the percentage of sunburned fruit harvested, but there was no consistent effect on fruit size, color, flesh firmness, or soluble solids.

Open access

Stephen S. Miller

Abstract

Growth of ‘Topred Delicious’ (Malus domestica Borkh)/Malling Merton (MM) 111 apple trees during the first 5 years in the orchard was significantly affected by the orchard floor management system. Trees grown in a mowed sod were smaller and had a significantly lower yield efficiency (kg/cm2) than those grown under cultivation or a herbicide strip system. N source or rate did not influence growth or average yield/tree; fruit size and bitter pit development were significantly greater where a complete fertilizer (10N-4P-8K) was applied. N increased tree growth under sod but not under a cultivated or herbicide strip managment system. Growth response in the first year was increased when larger-sized trees were planted under a weed-free management system and trees were headed to 76 cm.

Open access

Stephen S. Miller

Abstract

In the paper, Effect of Preharvest Antitranspirant Sprays on the Size and Quality of ‘Delicious’ Apples at Harvest by Stephen S. Miller (J. Amer. Soc. Hort. Sci. 104(2):204-207.1979), lines 2 and 3 in the third paragraph of the introduction should read: “A 1.0% wax emulsion applied to ‘Delicious’ and ‘Golden Delicious’ apples had no effect on fruit size(13);…”

Open access

Stephen S. Miller

Abstract

A commercial formulation of N-(phenylmethyl) lH-purin-6-amine plus gibberellin A4A7 (Promalin) was applied to ‘Delicious’ apples (Malus domestica, Borkh.) from 1975 to 1978 in 2 geographic locations at rates of 12.5 to 50 ppm. Promalin at 25 ppm increased fruit weight, length/diameter ratio (L/D), and percent “typey” fruit at both a cool mountain location and at a lower warm elevation. The effect on “typiness” in the warm growing area did not appear to be of commercial significance, but the increase in fruit weight did appear significant under these conditions. Response varied with strain. Addition of a spray adjuvant, Triton CS-7, at the lower elevation, did not improve response. Rates of 12.5 or 25 ppm applied at petal fall of the “king” blossom appeared to be equally effective under high temperature conditions conducive to oblate fruits.

Open access

Stephen S. Miller

Abstract

Sprays of poly-l-p-methen-8-9-diyl (Vapor Gard) or di-l-p-menthene (Wilt Prüf NCF), two antitran-spirants, or emulsifiable A-C polyethylene and octyl phenoxy polyethoxy ethanol (Plyac), a latex type spray adjuvant, at 0.5, 1.0 and 2.0% applied 14 days before “normal” harvest generally increased the size of ‘Stark-rimson Delicious’ apples (Malus domestica Borkh.) over unsprayed controls under conditions of low soil moisture. Antitranspirant or spray adjuvant treatments had little or no effect on average fruit diam when applied to trees growing under adequate soil moisture. The rate of chemical application had an effect on the fruit size response. Results indicated no additional benefit in fruit size when fruit were harvested 21 days after treatment (7 days after normal harvest). Treatments generally reduced fruit firmness and hastened the loss of starch from the fruit flesh.

Open access

Stephen S. Miller

Abstract

Pressure injection of certain plant growth regulators into pruned and unpruned apple (Malus domestica Borkh.) seedlings reduced terminal growth and increased lateral development within 7 weeks of injection. One ml of daminozide (butanedioic acid mon-(2, 2-dimethylhydrazide), AVG (aminoethoxyvinly glycine), MBR 18337 (N-(4-(ethylthio)-2-(trifluoro-methyl) phenyl (-methanesulfornamide) or PP333 [l-(4-chlorophenyl)-4, 4-dimethyl-2-(l,2,4-triazol-l-yl) pentan-3-01] reduced terminal extension growth over controls. PP333, the most effective growth inhibitor tested at 0.5 mg/ml, reduced terminal extension growth by 80% over controls. Top and root fresh weight were reduced on pruned seedlings. Only PP333 reduced top weight among the chemicals tested; root weight was not affected by chemical injections. Budbreak was increased significantly by BA (6-benzylamino purine), mepiquat-chloride (N-N-dimethyl-piperidinium-chloride) and AVG, but these chemicals had little or no effect on terminal extension growth.