scholarly journals Evaluating Twenty-eight Strains of `Delicious' Apple in Michigan

1996 ◽  
Vol 121 (6) ◽  
pp. 988-995 ◽  
Author(s):  
F.G. Dennis ◽  
J.G. Masabni ◽  
D.O. Ketchie

A cooperative experiment begun in 1980 was designed to evaluate the productivity and other characteristics of 16 spur and 12 standard strains of `Delicious' apple on two rootstocks (M.7 EMLA and MM.111 EMLA). All trees were propagated at one nursery, and plantings were established in Michigan, Washington, Oregon, Idaho, Indiana, and British Columbia. In Michigan, trees of standard strains were consistently larger than trees of spur strains 8 years after planting. Early yields were greater on M.7 EMLA than on MM.111 EMLA, but trees were more subject to leaning under heavy crops on M.7 EMLA. In general, spur-type strains yielded more fruit per unit trunk cross-sectional area than standard strains. Yield was more closely associated with fruit-setting ability than with flower density, and fruit size declined as fruit set increased. Length/diameter ratios and biennial bearing indices also differed significantly among strains.

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 539g-539
Author(s):  
Raouel Cano-Medrano ◽  
Rebecca L. Darnell

Exogenous applications of GA, have induced pathenocarpic fruit set in blueberry; however, size of GA,-treated fruit is smaller than pollinated fruit. The small fruit size in GA3-treated fruit may be related to either cell number and/or cell size. Thus, these parameters were examined throughout development in pollinated, non-pollinated and GA3-treated fruits. Fruit growth followed a double sigmoid pattern. During Stage I (0-25 DAA), fruit size in GA,-treated, pollinated, and non-pollinated fruits averaged 0.33, 0.39, and 0.16 g, respectively. There was little change in fruit size in Stage II (25-45 DAA). At ripening, fruit size averaged 1.7 g for GA,-treated and 2.6 g for pollinated fruits. Non-pollinated fruit abscised in Stage II. At anthesis, mesocarp cell number averaged 9910 cells per median cross sectional area and remained constant up to ripening. In Stage I, cell size in G A3-treated and pollinated fruits increased 7X and 9X respectively. Cell size in both fruit types increased 1.5X and 2.8X during Stage II and Stage 111, respectively. Fruit cell number was set at anthesis and differences in fruit size were due to differences in cell ellongation in Stage I.


1992 ◽  
Vol 117 (3) ◽  
pp. 380-383 ◽  
Author(s):  
Amy F. Iezzoni ◽  
Colleen A. Mulinix

Yield components were measured from 115 sour cherry (Prunus cerasus L.) hybrid seedlings from 13 full-sib families to investigate the potential of breeding for increased yield. Those families with the highest number of fruit and reproductive buds had the highest yields. In general, increased fruit size was not able to compensate for low fruit count. Fruit set and flower count per bud were inversely related, suggesting compensation between these two components. Yield components from six selections chosen for differing fruiting habits were measured for an additional 2 years. In year 1, those selections with a majority of their fruit on l-year-old wood had higher yield efficiencies (yield per branch cross-sectional area) than those with fruit on spurs; however, but year 3, the higher-yielding selections were those that fruited primarily on spurs. The data are discussed relative to selecting for yield in a sour cherry breeding program.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 590b-590
Author(s):  
Dwight Wolfe ◽  
Gerald Brown

`Redhaven' peach [Purnus persica (L.) Batsch] trees which were either own-rooted (OR) or June-budded (JB) the previous year were headed back at planting to either (1) 70-85 cm above the soil surface (CH, conventional heading) or (2) the first bud 20-30 cm above the soil surface (LH, low heading). Propagation method had no effect on fruit yield in 1988 or trunk cross-sectional area; however, total yield in 1987, and the cululative yield for 1987 and 1988 were significantly greater for JB trees than for OR trees. LH reduced survival of OR trees, but not the JB ones. Cold injury was greater for the OR trees than for the JB ones. Neither propagation nor heading height influenced bloom density, fruit set in 1987, or fruit size in 1988. However, OR trees which were conventionally headed produced larger fruits in 1987 than did JB trees the same year.


1981 ◽  
Vol 21 (108) ◽  
pp. 119
Author(s):  
KR Chapman ◽  
B Paxton ◽  
J Saranah ◽  
PD Scudamore-Smith

Five guava seedlines of Hawaiian origin, namely GA9-37, GA12-1 6, GA10-48, GA11-56 and GA9-39 were yield tested in coastal sub-tropical south-eastern Queensland. The work demonstrated that seedling guavas produce attractive yields comparable with overseas countries. First crop mean yields were 30.72 kg/tree after 18 months in the field, demonstrating the precocious bearing of the guava. Yields for second and third cropping years were 45.6 and 77.9 kg/tree. These yields equate to 24.7, 37.2 and 61.5 tonnes ha-1 at a planting density of 805 trees ha-1. Third crop yields give the attractive gross returns of around $15,000 ha-1, at current prices paid by processors in Queensland. No differences were found between seedlines in annual yields, accumulated crop yields, fruit Number/tree, annual yield per unit cross sectional area of butt (an index of fruitfulness) and accumulated yield per unit cross sectional area of butt. Within seedline, variability masked differential response and these aspects are discussed. Fruit yields and relative increase in butt cross sectional area of butt varied with cropping year. Fruit. number per tree and yield per unit cross sectional area of butt varied with years, as did fruit number per kg (an index of fruit size). The latter also varied with seedlines. These effects were attributed to water rationing in spring of the second crop year. Preliminary selection based on fruit quality aspects of individuals identified four individuals which are undergoing detailed processing assessment, namely GA9-39R1T2, GA11-56T7, GA11-56R5T2 and GA1 1-56R5T1. Two further individuals were selected for fresh fruit market testing, namely GA11-56T3 and GA11 -56R1T1. We believe that market development rather than horticultural problems to be overcome will dictate the success of the guava as a crop for Australia, since the guava is comparatively easy to grow and manage.


1971 ◽  
Vol 51 (2) ◽  
pp. 123-131 ◽  
Author(s):  
K. O. LAPINS

The study of 300 selections of Golden Delicious apple from plant material irradiated with gamma rays from a 60Co source resulted in the final selection of two clones that represent an improvement of the original cultivar in reduced russetting in fruit stem cavity; greatly reduced tendency to biennial bearing; and slightly lowered fertility, an advantage in Golden Delicious which tends to overset. In a single-tree first trial, about 50% of the examined clones showed reduced pollen stainability; the majority of the semi-fertile mutants had 51 to 55% stainable pollen. The number of seeds per fruit was very closely related to pollen fertility. A close relationship was found among indicators of fruit maturity, that is, skin color, flesh color, soluble solids, and titratable acidity of fruit at harvest. More detailed measurements of 14 promising selections in a replicated second test revealed highly significant differences among clones in number of seeds per fruit, the incidence of russetting in the stem cavity, shape of fruit, skin color of fruit, flesh color of fruit, biennial bearing index, weight of fruit, and trunk cross-sectional area of the tree. Clonal differences were nonsignificant in yield ratings for a four-year period, and the yield for 1969 in kg per cm2 of trunk cross-sectional area.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 475d-475
Author(s):  
Peter M. Hirst ◽  
David C. Ferree

One way in which rootstocks may influence production efficiency is by altering the number of spurs, and in particular reproductive spurs. However, rootstock influences on the morpholgy of shoots have not been quantified. Measurements were made on `Starkspur Supreme Delicious' trees growing on 17 rootstocks and planted in 1984 as part of the NC-140 regional rootstock trial. In each of the 6 years from 1988-1993, the length of the 2-year old section of wood of selected branches was measured and the number of spurs, flowers and shoots counted. For all rootstocks, trunk cross-sectional area was closely related to shoot length. Trees on P.22 (the most dwarfing rootstock in the planting) had shoot lengths 40-50% of those of trees on seedling rootstocks. For each rootstock, there was a strong negative relationship between shoot length and spur density, but there was not a common relationship among rootstocks. Similarly, flower number per shoot was also related to shoot length with different relationships for each rootstock. Flower density was not related to vigor for any of the rootstocks.


HortScience ◽  
2017 ◽  
Vol 52 (9) ◽  
pp. 1233-1240 ◽  
Author(s):  
James R. Schupp ◽  
H. Edwin Winzeler ◽  
Thomas M. Kon ◽  
Richard P. Marini ◽  
Tara A. Baugher ◽  
...  

Pruning is the cutting away of vegetation from plants for horticultural purposes. Pruning is known to reduce apple tree size, increase fruit size and quality, and decrease yield. Methods for studying the effects of varying degrees of severity of pruning on a whole-tree basis have used qualitative descriptions of treatments rather than repeatable whole-tree quantitative metrics. In this study, we introduce a pruning severity index calculated from the sum of the cross-sectional area of all branches on a tree at 2.5 cm from their union to the central leader divided by the cross-sectional area of its central leader at 30 cm from the graft union. This limb to trunk ratio (LTR) was then modified by successively removing the largest branches of ‘Buckeye Gala’ to achieve six severity levels ranging from LTR 0.5 to LTR 1.75, with lower values representing more extreme pruning with less whole-tree limb area relative to trunk area. Pruning treatments were applied for three consecutive years and tree growth and cropping responses were observed for the first 2 years. With increasing pruning severity the following characteristics increased after seasonal growth: number of renewal limbs, number of shoots, shoot length, number of shoot leaves, shoot leaf area, final fruit set, fruit size, yield of large fruit, crop value from large fruit, soluble solids, and titratable acidity. The following characteristics decreased: limb age, number of secondary limbs, number of spurs, number of spur leaves, spur leaf area, the ratio of spur leaf area to shoot leaf area, fruit count per tree, yield, yield efficiency, crop value from small fruit, overall crop value, and sugar:acid ratio. The LTR provides a measurable way to define and create different levels of pruning severity and achieve consistent outcomes. This allows a greater degree of accuracy and precision to dormant pruning of tall spindle apple trees. The use of the LTR to establish the level of pruning severity allows the orchard manager to set crop load potential through regulation of the canopy bearing surface. This metric is also a necessary step in the development of autonomous pruning systems.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 886A-886
Author(s):  
Preston K. Andrews ◽  
Margaret L. Collier

Effects of crop load and time of thinning on productivity of young `Fuji'/M.9 apple trees were tested by hand blossom (B) or fruit (F) thinning to two crop densities (fruit number/trunk cross-sectional area). Heavy (H) crop densities resulted in higher yields in both 2nd and 3rd leaf than light (L) crop densities. Time of thinning had no effect on yields in either year. In the 2nd leaf, fruit size was largest from trees B thinned to L crop densities, and smallest from trees F thinned to either crop density from mid-June through harvest. Both 1° and 2° vegetative growth were greatest in noncropped trees, intermediate in trees with L crops, and least in trees with H crops. Noncropped 2nd-1eaf trees had the highest flowering indices (flower clusters/100 total buds) the following spring and H cropped trees had the lowest. The flowering index was higher when trees were B thinned in the 2nd leaf than when F thinned. In the 3rd leaf, fruit size was largest when borne on weak upright shoots, intermediate on spurs, and smallest on 1-year-old terminal wood. Fruit on spurs had the highest incidence of sunscald (17%) and fruit on weak upright shoots the lowest (8%). Previous-season crop densities affected current-season's vegetative and fruit growth.


1969 ◽  
Vol 49 (6) ◽  
pp. 655-658 ◽  
Author(s):  
R. G. Ross ◽  
A. D. Crowe ◽  
R. P. Longley

A five-year study was conducted on the effect of captan, dodine and dichlone on the performance of mature McIntosh apple trees. There were no significant differences in yield, trunk cross-sectional area, amount of bloom, fruit size and fruit color. Dodine injured 0.5% of the fruit in one year of the test and pre-cover sprays of dichlone caused some fruit russeting. The results indicate that any harmful effect of dichlone on yield occurs from pre-cover applications, or pre-cover followed by cover sprays.


Author(s):  
K. Hrotkó ◽  
L. Magyar ◽  
G. Simon

The first nine years' results of sweet cherry rootstock trial from Hungary are presented with the aim to select efficient rootstocks for the local ecological conditions. The trials were established in 1989 with 'Van' and 'Germersdorfi óriás' cultivars on the following rootstocks: mahaleb Sainte Lucie 64, Colt, MxM 14, MxM 97. All the trees were headed at 80 cm and trained to a modified Brunner-spindle system. Tree size and yield was measured every year, and the cumulative yield efficiency was calculated. Based upon the results, mahaleb cherry SL 64 is a vigorous rootstock with good compatibility and productivity. In comparison to SL 64. the trunk cross-sectional area and canopy spread of the 'Van' trees decreased by 10-15% on rootstock Colt, while the trees of 'Germersdorfi orias' on Colt roostock grew even larger than on SL 64. Considerable 30-40 % reduction of tree size was achieved on trees grafted on M x M hybrids. Trees of `Germersdorfi óriás' showed a similar tendency without significant differences. The cumulative yield efficiency of `Van' trees after nine years was highest on rootstock MxM 14, followed by Sainte Lucie 64. Trees on Colt and MxM 97 rootstocks showed low productivity. `Germersdorfi óriás' produced the highest cumulative yield efficiency on SL 64, followed by MxM 14 and Colt and last MxM 97. Biennial bearing index of heavy cropping 'Van' trees was smaller than that of `Germersdorfi óriás'. The trees of 'Van' on MxM 97 showed higher biennial bearing index, while 'Germersdorfi orias' on different rootstocks showed similar tendency, but without significant differences. MxM 14 and MxM 97 rootstocks reduced the crotch angle of the shoots on both sweet cherry varieties which is disadvantegous to spindle training. Slight suckering (1-3/year) of the rootstocks Colt, MxM 14 and MxM 97 were observed during the first few years.


Sign in / Sign up

Export Citation Format

Share Document