Studies on the Bearing Behavior and Yield Composition of the Avocado Tree

Inoue, Hiroaki; Takahashi, Bunjiro

doi:10.2503/jjshs.59.487

Cited by 13 publications

(6 citation statements)

References 4 publications

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“…In contrast, the number of mature fruit abscised did not vary with alternate bearing, suggesting that different mechanisms are responsible for abscission of immature versus mature fruit. Other researchers have reported large seasonal losses with tens to hundreds of thousands of flowers and hundreds to tens of thousands of fruit abscised (Cameron et al, 1952;Inoue and Takahashi, 1990;Lahav and Zamet, 1975;Slabbert, 1981). The present research is one of the few studies to specifically measure mature avocado fruit abscission.…”

Section: Discussionmentioning

confidence: 99%

“…For example, researchers in California found an average of 113 flowers per inflorescence (Salazar-García and and two to 13 floral shoots per 1-m branch every year . In the few studies designed to quantify flower abscission on a whole-tree basis, researchers found that individual avocado trees can lose tens of thousands (Inoue and Takahashi, 1990) or even hundreds of thousands (Cameron et al, 1952;Lahav and Zamet, 1975;Slabbert, 1981) of flowers in a single season. In addition to significant flower loss, many avocado cultivars are also characterized by high rates of immature fruit abscission (Davenport, 1982;Inoue and Takahashi, 1990;Lahav and Zamet, 1975;Slabbert, 1981) where thousands of fruit have been reported to abscise per tree in a single season (Lahav and Zamet, 1975;Slabbert, 1981).…”

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confidence: 99%

“…In the few studies designed to quantify flower abscission on a whole-tree basis, researchers found that individual avocado trees can lose tens of thousands (Inoue and Takahashi, 1990) or even hundreds of thousands (Cameron et al, 1952;Lahav and Zamet, 1975;Slabbert, 1981) of flowers in a single season. In addition to significant flower loss, many avocado cultivars are also characterized by high rates of immature fruit abscission (Davenport, 1982;Inoue and Takahashi, 1990;Lahav and Zamet, 1975;Slabbert, 1981) where thousands of fruit have been reported to abscise per tree in a single season (Lahav and Zamet, 1975;Slabbert, 1981). Researchers report that most fruit abscission occurs within a few months of the end of bloom, with high rates of fruit abscission in the spring and summer followed by gradually declining rates of fruit abscission and negligible abscission through the fall as developing fruit approached maturity (Adato and Gazit, 1977;Lahav and Zamet, 1975;Perez et al, 1988).…”

mentioning

confidence: 99%

“…Researchers report that most fruit abscission occurs within a few months of the end of bloom, with high rates of fruit abscission in the spring and summer followed by gradually declining rates of fruit abscission and negligible abscission through the fall as developing fruit approached maturity (Adato and Gazit, 1977;Lahav and Zamet, 1975;Perez et al, 1988). Final wholetree fruit set ranges from a low of 0.001% for 'Bacon' trees in Japan (Inoue and Takahashi, 1990) to a high of 0.07% for California 'Fuerte' trees (Cameron et al, 1952), though the intensity, timing, and longevity of the abscission periods varies with cultivar and location. Taken together, these studies indicate that avocado flower and fruit abscission are excessive.…”

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confidence: 99%

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

Garner¹,

Lovatt²

2008

J. Amer. Soc. Hort. Sci.

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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.

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Section: Discussionmentioning

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

Garner¹,

Lovatt²

2008

J. Amer. Soc. Hort. Sci.

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“…Avocado and many other subtropical fruit tree crops are characterized by excessive flower and fruit abscission. Thousands of avocado flowers and immature fruit abscise in a single season (Cameron et al, 1952;Garner and Lovatt, 2008;Inoue and Takahashi, 1990;Lahav and Zamet, 1975;Slabbert, 1981), resulting in extremely low fruit set (<0.1%), even in healthy, well-managed orchards (Whiley and Schaffer, 1994). Outcrossing might be a key factor in the retention of avocado flowers and fruit.…”

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confidence: 99%

The Impact of Outcrossing on Yields of ‘Hass’ Avocado

Garner¹,

Ashworth²,

Clegg³

et al. 2008

J. Amer. Soc. Hort. Sci.

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‘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.

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