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  • Author or Editor: K. C. Short x
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Abstract

A combination of mechanical and hand pruning each year from 1971-1976 reduced pruning time over that of hand pruning alone for ‘Delicious’ apple (Malus domestica Borkh.). Yield was not significantly affected by pruning method with one exception in 1975. The use of the mechanical pruner destroyed the framework of the tree by inducing a thick canopy and reducing light penetration. Yield was increased by limb positioning at both the 2.3- and 3.0-m spacings. In 1974, higher yields were obtained with the 1.5-m spaced trees and in 1979 with the 3.0-m spaced trees. Average fruit weight was less for the 1.5-m spaced trees than for the 3.0-m spaced trees.

Open Access

Abstract

A method is described whereby relative humidity is reduced in the atmosphere of agar-solidified tissue cultures. Plantlets of chrysanthemum (Chrysanthemum X morifolium Ramat.) cultured under low humidity exhibited a high mortality rate and those that survived were smaller and had few roots. Severe retardation of stomatal development occurred under reduced humidity and mature stomata had considerably narrower apertures than did plantlets grown at about 100% relative humidity. Plantlets of cauliflower (Brassica oleracea L. Botrytis group) cultured under reduced humidity also exhibited reduced growth but, in addition, developed large quantities of surface wax and had lower rates of water loss. The results are discussed in relation to the potential uses of the technique for acclimatization of plantlets prior to transfer to soil.

Open Access

Abstract

Adequate fruit thinning of ‘Loring’ peach [Prunus persia (L.) Batsch] was achieved with single applications of (2-chloroethyl)-methylbis (phenylmethoxy) silane (CGA 15281) at concentrations of 240, 360, and 480 ppm applied at seed length of 8.8 mm and 2 applications at 240 and 360 ppm applied 7 days apart at 8.8 and 10.8 mm seed lengths in 1978. Additional hand thinning following treatment was required. In 1979 adequate thinning was achieved with 1 application of 240 ppm applied at seed length of 13.9 mm or 480 ppm applied at an 8.5-mm seed length. Yields from these treatments were reduced but did not differ from the control treatment. Multiple applications and higher rates resulted in over-thinning and reduced yields. The sensitivity of fruit to thinning appeared to increase with increased seed length. In 1978, foliage injury occurred at all rates and the severity of injury increased at higher concentrations and multiple applications. However, no foliage injury was observed in 1979.

Open Access

Abstract

Flower color in African violet (Saintpaulia ionantha Wendl.) is due to the presence of anthocyanidin-3-rutinoside-5-glucosides. Blue-flowered cultivars contained malvidin-3-rutinoside-5-glucoside, and a naturally occurring light blue mutant obtained by in vitro culture contained 80% less of the pigment. African violets with red petals contained peonidin-3-rutinoside-5-glucoside and pink-petalled cultivars contained pelargonidin 3-rutinoside-5-glucoside. African violets with light pink flowers contained about 80% of the pelargonidin found in cultivars with dark pink petals. The petals of a plant with speckled red and pink flowers, which had been produced from petioles of a red-flowered African violet following X-irradiation, contained peonidin and pelargonidin, respectively, in the red and pink petal sectors.

Open Access

Abstract

Three rootstock—Elberta seedling (Elb), Lovell seedling (Lov), and Vila Fria seedling (VF)—were evaluated on an old peach-orchard site to determine their susceptibility to nematodes and their effect on growth, yield, survival, and foliar nutrient content of ‘Loring’ peach [Prunus persica (L.) Batsch]. During the first 6 years of the orchard's life, mortality rates of the trees were 18% (Elb), 21% (Lov), and 47% (VF). Rootstock did not affect tree height, spread, trunk circumference, or yield the first 3 crop years. However, Lov produced higher yields the 4th crop year and had a greater cumulative yield for the first 4 crop years than Elb or VF. When tree loss was taken into account, tree yield per hectare did not differ with Lov and Elb but was lower with VF. Rootstock did not affect nutrient level in the foliage. Nematode populations were low in the orchard and were unaffected by rootstock. Tree loss, yield differences, and cropping efficiency of trees on the different rootstock could not be accounted for by foliar nutrient levels, nematode populations, tree vigor, or size.

Open Access