Masters Theses

Date of Award

12-1992

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

Dennis E. Deyton

Committee Members

David L. Coffey, Carl E. Sams, David W. Lockwood

Abstract

‘Redhaven' peach trees on Lovell rootstocks were established In 1985 to compare the effects of production systems of various training systems and tree densities on tree growth, yield and light penetration. Trees were established in nonsupported systems of open vase, perpendicular Y, and central leader at tree densities from 299 to 1794 trees/ha. Trees were also established in Tatura Trellis and Palmette Trellis at 897 trees/ha and MIA Trellis at 1196 trees/ha. Growth differences were evident by the second growing season. Trunk diameters in 1991 were asymptotically smaller as tree density increased from 299 to 1794 trees/ha. Trunk diameters of trees grown at the highest density were 44% smaller than trees at the lowest density. Tatura Trellis trees grown at 897 tree/ha yielded approximately twice as much fruit in the fourth growing season as the conventional open vase trees grown at 299 trees/ha. Yield of open vase trees in the fourth growing season increased 30% and 45% by increasing tree density 50% and 100%, respectively, compared to the conventional spacing (299 trees/ha).

Labor needed for dormant pruning increased linearly as tree density increased. Harvest efficiency in 1991 was highest for open vase trees. Fourteen and 26% more fruit were harvested per hour from open vase trees than from the perpendicular-Y and central leader trees grown at the same density (598 trees/ha).

The higher yields in the first production year from high density systems with freestanding trees compensated for the additional establishment cost when compared to the conventional open vase system (299 trees/ha).

Perpendicular-Y and Tatura Trellis trees maintained the highest light penetration at 1.2 and 2.1 m heights. Light levels in the center of central leader and palmette trees were below 20% of full sunlight in May. The light levels in mid scaffold canopy at 1.2 m height were below 20% of full sunlight in all systems in May, 1990. Levels of light at 2.1 m height, mid side canopy were above 20% of sunlight in all systems except central leader trees grown at 1794 trees/ha. Light levels were generally above 30% full sunlight in the tree center at 1.2 and 2.1 m heights of open vase, perpendicular-Y, Tatura Trellis and MIA Trellis systems.

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