Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: I. Schechter x
Clear All Modify Search
Authors: and

Annual yields per tree for `Starkspur Supreme Delicious' apple (Malus domestica Borkh.) trees on nine size-controlling rootstock were related linearly to number of fruit per tree at harvest each year, independent of rootstock. Mean fruit weight was inversely and less closely related to number of fruit per tree when adjusted for tree size (fruit load). Annual yield-fruit count data for 9 years analyzed together showed that the number of fruit per tree was the principal factor determining yield, regardless of rootstock or tree age. A curvilinear relationship between yield and fruit count per tree during 9 years suggests that the sink strength of an apple crop is nearly, but not precisely, proportional to the number of fruit per tree.

Free access
Authors: and

After 12 growing seasons, `Starkspur Supreme Delicious' apple trees on 9 rootstock genotypes from very vigorous (MAC 24) to very dwarfing (M.27 EMLA) were divided into branches, trunk, rootstock shank, and roots, and total fresh and dry weights of each component determined. Final tree dry weight (DW) ranged from 2 kg (M.27 EMLA) to 90 kg (MAC 24). Both total top DW and total tree DW (including roots) were closely and linearly related to final trunk cross-sectional area (TCSA). Both total cumulative fruit fresh weight and DW per kg final tree DW increased curvilinearly with smaller final TCSA. The percentage of cumulative fruit DW plus final tree DW in fruit increased curvilinearly with smaller final TCSA. Although 9 distinct rootstock genotypes of widely different vigors were included, the close relationships of tree DW and the distribution of DW between fruit vs. wood to final TCSA suggested that rootstock effects on both vigor and productivity were mediated through a single overall mechanism.

Free access

Leaf characteristics of mature `Sturdeespur Delicious'/MM.106 apple trees (Malus domestica Borkh.) were studied in two experiments. In 1989 canopy foliage on fruiting trees was divided into shoot leaves, leaves on nonfruiting spurs, and leaves on fruiting spurs. Shoot leaves were the heaviest, the largest, and contained the highest internal gas volume and chlorophyll content. The two spur-leaf types differed in their leaf characteristics except for stomate density. In 1990 shoot and spur leaves on nonfruiting spurs on fruiting trees had lower leaf water content than those leaves on nonfruiting trees. All other shoot-leaf characteristics were similar. Leaves on nonfruiting spurs on nonfruiting trees were larger than those on fruiting trees.

Free access

Mature `Macspur McIntosh'/MM.106 apple trees (Malus domestica Borkh.) trained to the central-leader (CL) tree form were converted to the palmette-leader (PL) tree form in 1987 by removal of east- and west-oriented scaffolds in the upper canopy. Control trees were pruned to maintain the CL form. Dormant pruning in subsequent seasons maintained either tree form. No summer pruning was done. Canopy light levels along horizontal transects 1 m above the soil and vertical transects, both through the center of the canopy, were unaffected by tree form or transect direction. Yields were significantly lower for PL trees in 1987 and 1989, while yield efficiency was reduced in PL trees in all 3 years. Fruit size, trunk cross-sectional area growth, and foliar macronutrient content were unaffected by tree form. Fruit color development in both the upper and lower halves of the canopy was not influenced by tree form during the study.

Free access

Mature `Macspur McIntosh'/MM.106 trees trained to the CL tree form were converted to the PL tree form in 1987 by removal of east- and west-oriented upper scaffold limbs. Control trees were pruned to maintain the CL form. Dormant pruning in later years maintained either tree form. No summer pruning was used in this study. Canopy light levels along horizontal transects at one m above the soil and vertical transects, both through the center of the canopy, were unaffected by tree form or transect direction. Yields were significantly lower for PL trees in 1987 and 1989, while yield efficiency was reduced in PL trees in all 3 years. Fruit size, trunk cross-sectional area, and foliar macro-nutrient content were unaffected by tree form during this study. Fruit color development in both the upper and lower halves of the canopy was uninfluenced by tree form.

Free access