Effects of clonal rootstocks on ‘Hass’ avocado yield components, alternate bearing, and nutrition

2007 ◽  
Vol 82 (3) ◽  
pp. 460-466 ◽  
Author(s):  
Michael V. Mickelbart ◽  
Gary S. Bender ◽  
Guy W. Witney ◽  
Carol Adams ◽  
Mary Lu Arpaia
Keyword(s):  
Yield Components ◽  
Alternate Bearing ◽  
Hass Avocado

scholarly journals The Relationship Between Flower and Fruit Abscission and Alternate Bearing of ‘Hass’ Avocado

2008 ◽  
Vol 133 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Lauren C. Garner ◽  
Carol J. Lovatt
Keyword(s):  
Developmental Stages ◽  
Weather Conditions ◽  
Nutrient Status ◽  
Persea Americana ◽  
Alternate Bearing ◽  
Immature Fruit ◽  
Fruit Abscission ◽  
Reproductive Structures ◽  
Independent Process ◽  
Hass Avocado

Despite profuse flowering, ‘Hass’ avocado (Persea americana Mill.) yields are low because of excessive flower and fruit abscission. Whether the dynamics of flower and fruit abscission are influenced by or contribute to alternate bearing, the production of a heavy on-crop followed by a light off-crop that is characteristic of many avocado cultivars, remains unresolved. The objective of this research was to determine whether abscission of reproductive structures from ‘Hass’ avocado trees during specific developmental stages, including flowering, fruit development, and fruit maturity, was influenced by crop status of the current or preceding year. Abscised reproductive structures were collected from commercially bearing trees during two complete crop years. Flower abscission began at about the same time but peaked 1 month later in the off-crop year compared with the on-crop year. Peak abscission rates were lower during the off-crop year than the on-crop year (compare 1836 ± 403 to 5378 ± 856 flowers per day and 50 ± 18 to 280 ± 23 immature fruit per day, respectively). The off- or on-crop status of the tree did not influence the percentage fruit set, average fruit diameter, or biomass of individual fruit that abscised at similar phenological stages. Furthermore, flower and fruit abscission were not influenced by the number of mature fruit from the previous year's crop. In both years of the research, as immature fruit abscission declined, abscission of the preceding year's crop increased, indicating that the processes were controlled independently. During the study, neither weather conditions nor tree nutrient status were associated with key abscission events. Taken together, these results provide evidence that the previous year's yield does not influence flower or fruit abscission and the seasonal abscission of reproductive structures is an independent process that does not contribute to alternate bearing of ‘Hass’ avocado.

scholarly journals The Impact of Outcrossing on Yields of ‘Hass’ Avocado

2008 ◽  
Vol 133 (5) ◽  
pp. 648-652 ◽  
Author(s):  
Lauren C. Garner ◽  
Vanessa E.T.M. Ashworth ◽  
Michael T. Clegg ◽  
Carol J. Lovatt
Keyword(s):  
Microsatellite Markers ◽  
Fruit Set ◽  
Persea Americana ◽  
Primary Factor ◽  
Alternate Bearing ◽  
Fruit Abscission ◽  
Significant Relationships ◽  
Outcrossing Rates ◽  
Hass Avocado ◽  
The Impact

‘Hass’ avocado (Persea americana Mill.) is characterized by excessive flower and fruit abscission, resulting in extremely low fruit set. Low outcrossing rates might be a factor contributing to low yields. It is hypothesized that self-fertilized flowers and resulting fruit abscise at a much higher rate than fruit that are the product of outcrossing. However, significant relationships between outcrossing rates and yields have only been established in a few avocado studies. The objective of this research was to investigate the importance of outcrossing to yield in a commercial ‘Hass’ orchard containing ‘Bacon’, an effective pollinizer of ‘Hass’. Microsatellite markers were used to determine the rate of outcrossing of fruit persisting to harvest on ‘Hass’ trees. Experiments were conducted during sequential on- and off-crop years. During both years, outcrossing rates were not related to yield or alternate bearing. These results indicate that outcrossing was not the primary factor affecting flower and fruit persistence and ultimately yield in this orchard for the two sequential years of this research.

scholarly journals Effect of complementary irrigation on yield components and alternate bearing of a traditional olive orchard in semi-arid conditions

2016 ◽  
Vol 14 (2) ◽  
pp. e1203 ◽  
Author(s):  
Enrico M. Lodolini ◽  
Serena Polverigiani ◽  
Saed Ali ◽  
Mohammed Mutawea ◽  
Mayyada Qutub ◽  
...  
Keyword(s):  
Vegetative Growth ◽  
Yield Components ◽  
Fruit Size ◽  
Olive Tree ◽  
Residual Effects ◽  
Oil Yield ◽  
Alternate Bearing ◽  
Positive Effects ◽  
Arid Conditions ◽  
Semi Arid

Traditional olive orchards are usually not irrigated in the Mediterranean basin, but at those latitudes, the yearly rainfall is frequently insufficient to support equilibrated vegetative growth and high fruit and oil production. This three-year field study investigated the effect of complementary irrigation on olive tree vegetative growth, fruit and oil yield during a biennial alternate bearing cycle in a traditional grove under semi-arid conditions. Adult olive trees (Olea europaea L. cv. Nabali Baladi) were subjected to complementary irrigation in 2011 and 2012 ('on' and 'off' years, respectively) with 6, 10, 15 or 20 m3 of water per tree per season, which corresponded to 14.2%, 23.8%, 35.7% and 47.6% of the whole seasonal evapotranspiration (42 m3 of water per year), respectively. Rain-fed trees were used as control. In 2013, no complementary irrigation was supplied, and any residual effects on the yield components were determined. Results showed that none of the irrigation regimes affected vegetative growth, or olive fruit size (mesocarp and endocarp), as fresh and dry weights. The fruit and oil yield per tree increased compared to the rain-fed conditions only when the threshold of 15 m3 was exceeded, thus inducing a higher crop load compared to the rain-fed control during the 'off' and even further during the 'on' year. No residual effects were registered in 2013. The study showed that complementary irrigation of at least 35% of the seasonal water requirement can produce remarkable positive effects on fruit yield especially during 'on' bearing years.

scholarly journals Influence of gibberellin inhibitors applied during flowering of nonirrigated 'Hass' avocado trees

2018 ◽  
Vol 53 (8) ◽  
pp. 918-923 ◽  
Author(s):  
Bruna do Amaral Brogio ◽  
Simone Rodrigues da Silva ◽  
Tatiana Cantuarias-Avilés ◽  
Sérgio Figueiredo Angolini ◽  
Edypol Guilherme Baptista ◽  
...  
Keyword(s):  
Shoot Growth ◽  
Block Design ◽  
Fruit Shape ◽  
Persea Americana ◽  
Fruit Yield ◽  
Gibberellin Biosynthesis ◽  
Alternate Bearing ◽  
Water Control ◽  
Hass Avocado ◽  
Prohexadione Calcium

Abstract: The objective of this work was to evaluate the effect of different gibberellin biosynthesis inhibitors on shoot growth above the panicle, as well as on fruit yield, size, and shape of nonirrigated 'Hass' avocado (Persea americana) trees. The experiment was carried out in a randomized complete block design, with five treatments, four replicates, and 40 trees. From 2013 to 2015, the following treatments were applied at full bloom, as foliar sprayings: water (control), 250 mg L-1 prohexadione-calcium, 2,500 mg L-1 trinexapac-ethyl, 1,750 mg L-1 paclobutrazol, and 350 mg L-1 uniconazole; the first two are acylcyclohexanediones and the last two, triazoles. Fruit yield, yield efficiency, and alternate bearing were not affected by the application of plant growth regulators. However, the gibberellin inhibitors increased fruit size and modified the fruit shape of nonirrigated 'Hass' avocado. Uniconazole reduces shoot growth above the panicle, and this effect may vary depending on environmental conditions, especially water supply.

scholarly journals Use of GA3 to Manipulate Flowering and Yield of `Hass' Avocado

2000 ◽  
Vol 125 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Samuel Salazar-García ◽  
Carol J. Lovatt
Keyword(s):  
Early Stage ◽  
Persea Americana ◽  
Yield Reduction ◽  
Alternate Bearing ◽  
Concomitant Increase ◽  
Vegetative Shoot ◽  
Inflorescence Development ◽  
Initial Development ◽  
Shoot Number ◽  
Hass Avocado

Avocado trees (Persea americana Mill.) bearing a heavy crop produce a light “off” bloom the next spring. This results in a light crop and a subsequent intense “on” bloom the year after. The objective of the study was to quantify the effects of GA3 canopy sprays applied to `Hass' avocado trees during the months preceding an “off” or “on” bloom on inflorescence and vegetative shoot number and yield. The experiment was initiated approximately seven months before an anticipated “off” bloom in an attempt to increase flowering intensity and yield. GA3 (25 or 100 mg·L-1) was applied to separate sets of trees in September (early stage of inflorescence initiation), November (early stage of inflorescence development), January (initial development of the perianth of terminal flowers), March (cauliflower stage of inflorescence development; only 25 mg·L-1), or monthly from September through January (only 25 mg·L-1). Control trees did not receive any treatment. GA3 (100 mg·L-1) applied in September reduced inflorescence number in both years, but not yield. GA3 (25 or 100 mg·L-1) applied in November before the “on” bloom reduced inflorescence number with a concomitant increase in vegetative shoot number and 47% yield reduction compared to control trees. This treatment might provide avocado growers with a tool to break the alternate bearing cycle by reducing yield in an expected “on” crop year to achieve a higher yield the following year. GA3 (25 mg·L-1) applied in November or January stimulated early development of the vegetative shoot of indeterminate inflorescences. January and March applications did not affect the number of flowering or vegetative shoots produced either year. GA3 (25 mg·L-1) applied in March at the start of an “off” bloom increased 2-fold the production of commercially valuable fruit (213 to 269 g per fruit) compared to the control.

scholarly journals The Effect of Avocado Clonal Rootstock on Productivity and Tree Vigor of `Hass' Avocado

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 795C-795
Author(s):  
M.L. Arpaia ◽  
G.S. Bender ◽  
G.W. Witney
Keyword(s):  
Southern California ◽  
Maximum Yield ◽  
Tree Size ◽  
The Other ◽  
Alternate Bearing ◽  
High Productivity ◽  
Yield Efficiency ◽  
Canopy Volume ◽  
Hass Avocado

A project evaluating the performance of cv. Hass on eight clonal avocado rootstocks—G755A, G755B, G755C, Duke 7 (D7), Borchard (BR), D9, Toro Canyon, and Topa Topa was established in southern California in 1986. Two additional rootstocks, Thomas and G1033, were added in 1987. Of the trees planted in 1986, the BR and D7 rootstocks have consistently had the highest total yields for all rootstocks, whereas the three G755 selections have had the lowest productivity. No differences in productivity between the two rootstocks planted in 1987 have been detected. The influence of rootstock on the magnitude of alternate bearing will be discussed, although the oscillation in yield is greater for the higher-yielding rootstocks. Tree size has been measured throughout the study. The BR selection has consistently produced a larger tree, even though it has continued to have high productivity. There are no consistent differences between the other rootstocks. Yield efficiency, measured as the kg fruit/m3 of canopy volume has been calculated. In selections that are prone to severe alternate bearing, the swing in yield efficiency is also the greatest. The data thus far suggests that a yield efficiency of ≈2.5 kg fruit/m3 canopy volume is the maximum yield possible for California `Hass' avocado.

Effect of sowing date and nitrogen on yield, components yield and oil characteristic of medicinal flax

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
MM Rahimi ◽  
G Normohamadi ◽  
A Aeinehband
Keyword(s):  
Yield Components ◽  
Sowing Date
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