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  • Author or Editor: R. E. C. Layne x
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‘Harko’ is an attractive, freestone, yellow-fleshed, midseason nectarine [Prunus pérsica var. nectarina (Ait.) Maxim.] that ripens about 5 days after ‘Nectared 2’ and about 6 days before ‘Nectared 4’. It has shown greater cold hardiness and disease tolerance as well as superior fruit quality to ‘Nectared 2’, ‘3’, and ‘4’, respectively. It was introduced in 1974 to meet the need for a better adapted midseason nectarine for the Ontario fresh market.

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‘Hardired’ is an exceptionally cold hardy nectarine [Prunus persica var. nectarina (Ait.) Maxim.] that ripens 9 days after ‘Nectared 2’ and 2 days before ‘Nectared 4’. It is an attractive, yellow-fleshed, freestone that is similar in most respects to ‘Harko’ but ripens 4 or 5 days later. It was released in 1974 to extend the season of ‘Harko’, and to extend the areas of nectarine culture in Ontario. ‘Hardired’ in natural and controlled freezing tests exceeds the cold hardiness of all nectarine cultivars and advanced selections in the Harrow collection (16 cultivars, 9 selections) and compares with ‘Reliance’ and ‘Babygold 8’ peach in bud hardiness.

Open Access
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Abstract

The effects of irrigation and tree density on peach [Prunus persica (L.) Batsch cv. Harken/Siberian C] production were investigated over 11 years. Irrigation improved growth of peach trees, lowered levels of winter injury and perennial canker (Leucostoma spp.), and promoted tree survival. Annual and cumulative marketable yields were increased, especially in the later years. Tree density did not affect perennial canker, winter injury, or tree survival. Reducing tree spacing increased resulted total growth per hectare and annual and cumulative marketable yields. Irrigation and density treatments usually did not interact and had an additive effect on growth and fruit production. The most productive management system (a combination of 50% available soil moisture and 536 trees/ha) resulted in accumulated yields over 8 years of 179 tonnes (t)/ha comparted with only 74 t/ha for the check treatment (no irrigation and 266 trees/ha).

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Abstract

A 2-year study was made of 2 methods of scheduling irrigation of peach (Prunus persica (L.) Batsch cv. Harken/Siberian C). In each year, irrigation schedules necessary to prevent the available soil moisture (ASM) from falling below 50% level in the top 30 cm were essentially the same, whether determined from direct measurement of soil moisture or predicted from a simplified Priestley and Taylor évapotranspiration model.

Open Access

Abstract

Eleven peach scion-rootstock combinations were evaluated for cold hardiness by controlled freezing after acclimation in controlled environments at temperatures of 20/14 or 10/4°C day/night and photoperiods of 9, 12 or 15 hours. Temperature and scion cultivar had much greater effects on cold hardiness of buds and bark than did photoperiod or rootstock. Trees held at 10/4° were more cold hardy than those held at 20/14°. ‘Siberian C’ scions were more cold hardy than ‘Harrow Blood’ or ‘Elberta’ scions. Short days increased cold acclimation of fruit buds at 20/14° but not at 10/4°. Rootstock influence on scion acclimation was small but some cultivar differences were apparent.

Open Access

Abstract

Four hedgerow types: oblique fan, canted oblique fan, modified central leader, and open center, in a peach (Prunus persica (L.) Batsch cv. Olinda) orchard were evaluated in 1975 and 1977 for their effect on deposition of captan (N-trichloromethyl-4-cyclohexene-l,2,dicarboximide). Within hedgerows captan residues on leaves were generally higher on bottoms than tops of trees but among hedgerows, leaf residues were higher on oblique fan. The higher leaf residues resulted in 10.8% more of the captan applied per tree retained by oblique fan compared to 31.7% intercepted by the other hedgerows. Ground deposits for oblique fan and open center averaged 11.7% but were 6.3% higher for canted oblique fan and modified central leader. Ground deposits did not relate to area below trees or hedgerow type but leaf residues and that unaccounted for related to tree canopy volume. Compared to the standard open center, oblique fan was 41% more efficient at intercepting captan, modified central leader 20% more efficient and canted oblique fan showed no improvement in efficiency. Hedgerows with smaller tree canopy volumes increased captan interception, reduced spray drift and thereby provided economic and environmental gains through more efficient captan use.

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Abstract

Flower buds and apical shoots of ‘Redhaven’ peach (Prunus persica (L.) Batsch) were shown to be slightly more cold hardy in the autumn and winter when propagated on seedlings of Siberian C than on those of Harrow Blood. Apical shoots consistently had higher levels of total carbohydrates, reducing sugars, and other carbohydrate fractions on Siberian C than on Harrow Blood seedlings from winter to spring. The cold hardiness of flower buds was closely correlated with the hardiness of apical shoots. In addition, both flower bud and shoot hardiness were closely correlated with total sugars, sucrose, and reducing sugars in the shoots from autumn to spring. However, hardiness of flower buds and apical shoots was not correlated with total carbohydrates or starch. The TI50, a new method of expressing the hardiness of apical shoots was an objective index of cold hardiness and somewhat analogous to the T50 method for expressing hardiness of flower buds.

Open Access
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Abstract

The trench profile method was used to map peach [Prunus persica (L.) Batsch cv. Harken/Siberian C] roots in an 11-year-old experimental orchard with 3 levels of irrigation and 3 tree densities. Roots near the drip line, 150 cm from the trunk, were mapped to a depth of 120 cm, while those 30 cm from the trunk were mapped to a depth of 240 cm. Location, number, and diameter of roots near the drip line were greatly affected by irrigation and only moderately affected by tree density. The total number, and number of small-diameter (<2 mm) roots were highest in nonirrigated plots and decreased with increasing levels of irrigation. A similar but much reduced pattern was evident for medium- (2 to 5 mm) and large- (>5 mm) diameter roots. Irrigation promoted shallow rooting near the drip line. Trees receiving the low and high level of irrigation had 35% and 42%, respectively, of their roots in the top 30 cm of soil, compared with only 18% for those in nonirrigated plots. At depths of 30 to 120 cm in nonirrigated plots, 82% of the roots near the drip line were found in these soil layers, compared with 65% for the low and 58% for the high level of irrigation. Tree density had no effect on total root number near the drip line, although there was an increase in root number with an increase in tree density 90 to 120 cm from the trunk on both sides of the tree, and a decrease in root number with an increase in tree density within 60 cm of the trunk. Rooting occurred readily in the Ap, Bm, and Bt soil horizons, but very little rooting occurred in the gray sand comprising the Ck horizon, which had a high pH (7.8) and poor soil water retention characteristics.

Open Access

Abstract

An experimental peach (Prunus persica [L.] Batsch cv. Harken/Siberian C) orchard was planted on Fox sand in 1973 at 266, 358 and 536 trees/ha. The plots were either not irrigated or irrigated at a frequency necessary to prevent the available soil moisture (ASM) from falling below 25 or 50%. Irrigation stimulated tree growth in the earlier but not in the later years of the experiment. Growth was reduced by an increase in tree density especially in the later years at the highest density. Only in 50% ASM plots was growth not affected by high tree density. Irrigation (50% ASM) increased cumulative, marketable yields in the first 5 years of production by up to 9.7% while tree density (536 trees/ha) increased similar yields by up to 74.6% without irrigation and up to 99.5% with irrigation (50% ASM + 536 tree/ha). Irrigation consistently improved the proportion of large and medium-sized fruit while reducing the proportion of small, unmarketable fruit. Tree density had a smaller and less consistent influence on fruit size. Neither irrigation nor tree density adversely affected split pits, raw product fruit quality, cold hardiness or canker (Leucostoma spp.) susceptiblity. There were no significant interactions of irrigation and density treatments in any year, indicating that each treatment might be used to advantage without adversely affecting the other, at least in the first 7 years of growth and first 5 years of production.

Open Access

Abstract

Bearing trees of ‘Loring’, ‘Redhaven’ and ‘Babygold 5’ peach trees (Prunus persica (L.) Batsch) on Siberian C seedlings defoliated earlier than those on the other seedling rootstocks. Early cold acclimation of scions in the fall and scion cold hardiness in mid-winter were enhanced more by Siberian C seedlings than by those of the other seedling rootstocks. Bud survival and fruit set of ‘Redhaven’ and ‘Bablygold 5’ scions were greater on Siberian C seedlings than on any of the other seedling rootstocks following an outdoor cold stress at -23.4°C in January. The cold hardiness of phloem, cambium, and xylem stem tissues were closely correlated with each other in the fall, but were not correlated with cold hardiness of flower buds on the same shoots. Seedlings of Siberian C appeared to enhance early scion dormancy and they increased scion bud hardiness by as much as 4.7° in the fall, and 1.3° in mid-February, compared with those of other rootstocks tested.

Open Access