FLOWERS, FRUITLETS AND FRUIT DROP IN AVOCADO TREES - 1999 Revista Chapingo Serie Horticultura 5

Aug 20, 2026

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Records the abscission stages of buds, flowers and fruitlets in avocado trees across early spring, summer and winter. Using 12 “Fuerte” trees and 60-tree assessments for “Ettinger”, “Fuerte” and “Hass”, the study quantifies total organs shed and relates drop patterns to yield components and meteorological factors. Results show abscission processes were largely independent of flowering intensity; fruitset remained minimal, with only a small fraction reaching mature fruit and abscised dry mass totaling about 15% of crop.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

SUMMARY

INTRODUCTION

METHODS

Experimental design and sampling

Drop classification periods

RESULTS

Bowl counts vs total drop

Buds, flowers and fruitlets abscission

Meteorological relationships

1999. Revista Chapingo Serie Horticultura 5: 95-100 FLOWERS, FRUITLETS AND FRUIT DROP IN AVOCADO TREES E. Lahav; D. Zamet Agricultural Research Organization, The Volcani Center, 50250 Bet Dagan, Israel. Email [vhlahav@.agri.gov.il](vhlahav@.agri.gov.il) SUMMARY The various stages of abscission of buds, flowers and fruitlets were recorded in the early spring in 12 ‘Fuerte’ trees. Summer fruitlet abscission was recorded in 60 trees of each cultivar: ‘Ettinger’,‘Fuerte’ and ‘Hass’ and winter fruit drop in 60 ‘Hass’ trees only. Total number of organs abscised was 0.230-1.277 million and the abscission process was independent of flowering intentsity. Total abscission balance for a ‘Fuerte’ tree showed that fruitset percentage was 1.5% but 99% of the fruitlets dropped and only 1% were picked. Thus only 0.015% of the flowers developed into mature fruits. No relationship was found between buds and flower abscission and yield. Increased production may be achieved by reducing summer drop in ‘Ettinger’ and ‘Hass’ or earlier drop in ‘Fuerte’. Total dry weight of abscised organs was only 15% of the crop. Therefore, the massive abscission is not the only factor determining avocado productivity. KEY WORDS: Persea americana , abscission, yield. INTRODUCTION Low avocado yields may result from reduced flowering or increased drop of flowers and fruitlets. Even under normal flowering and fruitset, increased drop will result in low productivity. Shedding of flowers and fruitlets must affect productivity and therefore deserves special attention. The relationship between amounts of flowers, fruitlets and various sizes of fruits shedded and productivity was investigated in the early 70’s. No other intensive research was done before or after, describing the various stages of drop in the avocado tree. Information about each of the drop stages may improve our understanding of affecting factors and therefore may improve productivity. Therefore we decided to bring forward the data of 30 years ago. METHODS The experimental plantation was planted in 1963 in Akko Experiment Station in the Western Galilee, Israel. ‘Ettinger’,‘Hass’ and ‘Fuerte’ trees, 8 years old were used for collecting data. The plantation received standard agrotechniques and the productivity was good. Since counting all kinds of drops along the season is extremely high labor consuming, a correlation was calculated between drop collected in bowls and total drop. Ten bowls of 20 cm diameter were placed under each experimental tree. The bowls were placed in two circles, one (4 bowls) and two (6 bowls) meters from the trunk. The bowls were 3 partially filled with water to avoid loss of flowers and fruitlets. In the same time all drop was collected by polyethylene sheets from 5 trees. In these trees bowls were also placed. The area of the 10 bowls was 0.31 m2 , about 1% of the total area of the tree. The correlation was calculated between the drop into the bowls and the total drop. Until mid-June drops were collected every two days and classified according to: buds, groups of buds, flowers and fruitlets. Fruitlets were divided according to their length (above 0.5 cm) . The survey was divided into three periods. 1. Abscission of buds, flowers and fruitlets Measured in bowls in 12 ‘Fuerte’ trees uniform in their size and with medium-good productivity. 2. Abscission in summer All fruitlets larger than 10 mm and fruits were counted from July to September 1970 and June to October 1971. The survey comprised 60 trees from each cultivar ‘Ettinger’,‘Fuerte’ and ‘Hass’. Fruit drop was analysed according to the total yield. 3. Abscission in winter Since the ‘Ettinger’ and ‘Fuerte’ cultivars are harvested in the late autumn the survey was conducted on the ‘Hass’ only. All fruits were counted during two seasons (1971/2 and 1973/4) . The second season had very strong wind storms. Each year the fruit of each tree was counted and weighted. RESULTS Abscission into

FAQs

How were the different abscission stages in avocado measured in the study?

Buds, flowers and fruitlets were collected using bowls placed under trees and, in parallel, total drop was gathered using polyethylene sheets from selected trees. Drops were counted and classified into defined periods across spring, summer, and winter.

What main finding relates abscission to flowering intensity and yield?

The abscission process was independent of flowering intensity, and no relationship was found between buds and flower abscission and yield, indicating that flower/bud drop alone does not explain productivity differences.

Which meteorological factors were linked to bud/flower versus fruitlet drop?

Bud and flower drop was mostly affected by wind speed, while fruitlet abscission was influenced by low temperatures and especially relative humidity.

Aug 20, 2026

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