Foliar-applied GA3 Advances Fruit Maturity and Allows Off-season Harvest of ‘Hass’ Avocado

Michoacán and Nayarit are, respectively, the largest and second largest avocado-producing states in Mexico. The main harvest of the ‘Hass’ avocado in both states is concentrated during November to December, which saturates the market and reduces the price of fruit and grower income. The goal of this research was to manipulate vegetative and reproductive growth of the ‘Hass’ avocado with properly timed foliar-applied plant bioregulators (PBRs) to shift the date of flowering and harvest to the period before or after the main harvest. Effects of canopy sprays of gibberellic acid (GA3) or prohexadione calcium (a gibberellic acid biosynthesis inhibitor) applied at different stages of tree phenology on inflorescence development, time of anthesis, date of legal maturity for harvest of ‘Hass’ avocado fruit, yield, and fruit size were quantified. No PBR treatment influenced the time of anthesis. A single or double foliar application of GA3 (50 mg·L−1) ≈4 months (July) before the expected date of main harvest (November) resulted in ‘Hass’ avocado fruit reaching legal maturity (mesocarp dry matter 21.5% or greater) 24.8 to 28.2 d earlier than those of untreated control trees with no negative effect on yield or fruit size.

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537 PB 043 ROWCOVER AND BLACK PLASTIC MULCH EFFECTS ON TOMATO PRODUCTIONS

HortScience ◽

10.21273/hortsci.29.5.508d ◽

1994 ◽

Vol 29 (5) ◽

pp. 508d-508

Author(s):

Ibrahim G. Rubeiz ◽

Marlene M. Freiwat

Keyword(s):

Air Temperature ◽

Total Yield ◽

Fruit Size ◽

Plastic Mulch ◽

Fruit Setting ◽

Negative Effect ◽

Black Plastic ◽

Effect On Yield ◽

Yield Time ◽

And Control

Tomato cv. Alwadi were grown under floating rowcover, black plastic mulch, mulch plus rowcover, or no protection i.e. control, for studying the effect on yield in terms of earliness, total yield and average fruit size. Early yield was significantly increased by the mulch treatment while the rowcover treatment yielded the least (P < 0.05). Total yield was increased by the mulch and mulch plus rowcover treatments, while the rowover and control treatments yielded the least (P < 0.05). Soil temperature at 10 cm depth varied between 1° to 2°C only under the different treatments. Air temperature under the rowcover exceeded 35 to 40°C on many days, hence causing fruit setting problems and resulting in reduced early yield under the rowcover. Our results show that earliness is enhanced by black plastic mulch, while the rowcover alone can have a negative effect on yield. Time of rowcover removal above the mulch warrants further research.

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Response of evergreen perennial tree crops to gibberellic acid is crop load-dependent: II. GA3 increases yield and fruit size of ‘Hass’ avocado only in the on-crop year of an alternate bearing orchard

Scientia Horticulturae ◽

10.1016/j.scienta.2011.08.033 ◽

2011 ◽

Vol 130 (4) ◽

pp. 753-761 ◽

Cited By ~ 3

Author(s):

Lauren Garner ◽

Grant Klein ◽

Yusheng Zheng ◽

Toan Khuong ◽

Carol J. Lovatt

Keyword(s):

Gibberellic Acid ◽

Fruit Size ◽

Alternate Bearing ◽

Crop Load ◽

Tree Crops ◽

Hass Avocado

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Prohexadione-Ca Reduces Russet and Does Not Negate the Efficacy of GA4+7 Sprays for Russet Control on ‘Golden Delicious’ Apples

HortScience ◽

10.21273/hortsci.42.3.550 ◽

2007 ◽

Vol 42 (3) ◽

pp. 550-554 ◽

Cited By ~ 2

Author(s):

Steven McArtney ◽

J.D. Obermiller ◽

A. Green

Keyword(s):

Shoot Growth ◽

Fruit Size ◽

Economic Benefits ◽

Fruit Weight ◽

Single Application ◽

Inhibitory Effects ◽

Fruit Maturity ◽

Golden Delicious ◽

Negative Effect ◽

Prohexadione Calcium

A series of four experiments were undertaken to evaluate the effects of individual and combined applications of prohexadione-Ca (P-Ca) and GA4+7 primarily on fruit russet, but also on fruit set, fruit weight, early season shoot growth, and fruit maturity of ‘Golden Delicious’ apples (Malus × domestica Borkh.). A single application of P-Ca (138 to 167 mg·L−1) at petal fall (PF) reduced the severity of russet in three of the four experiments; however, multiple applications of 20 ppm GA4+7 at 10-day intervals beginning at PF generally reduced russet more effectively than P-Ca. P-Ca did not reduce the efficacy of GA4+7 sprays for russet reduction. However, GA4+7 sprays reduced the inhibitory effects of P-Ca on shoot growth measured 30 days after PF. A single application of P-Ca at PF had no effect on mean fruit weight at harvest. Fruit size was lowest for the combined P-Ca and GA4+7 treatment in every experiment, although there was a significant interaction between P-Ca and GA4+7 sprays on mean fruit weight in only one experiment. There were no consistent effects of P-Ca and GA4+7 sprays, alone or in combination, on fruit maturity parameters at harvest. These data show that a single application of P-Ca at PF reduced russet severity, and the effects of P-Ca and GA4+7 sprays on russet can be additive. The economic benefits resulting from a reduction in russet severity after combined P-Ca and GA4+7 sprays will need to be balanced against their occasional negative effect on fruit size. Chemical names used: prohexadione-calcium [3-oxido-4-propionyl-5-oxo-3 cyclohexenecarboxylate formulated as Apogee (27.5% a.i.)].

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Timing Citrus and Avocado Foliar Nutrient Applications to Increase Fruit Set and Size

HortTechnology ◽

10.21273/horttech.9.4.607 ◽

1999 ◽

Vol 9 (4) ◽

pp. 607-612 ◽

Cited By ~ 22

Author(s):

Carol J. Lovatt

Keyword(s):

Foliar Application ◽

Persea Americana ◽

Flower Initiation ◽

Cumulative Yield ◽

Phenological Stages ◽

Inflorescence Development ◽

Nutrient Demand ◽

Washington Navel ◽

Foliar Nutrient ◽

Hass Avocado

The goal of this research was to identify the role essential nutrients play in the physiology of tree crops, and then to apply the nutrient as a foliar fertilizer to stimulate a specific metabolic process at phenological stages when nutrient demand is high. This approach has proven successful. A single winter prebloom foliar application of nitrogen as low-biuret urea [0.16 kg N/tree (0.35 lb N/tree)] to 30-year-old `Washington' navel orange (Citrus sinensis L. Osbeck) trees during flower initiation significantly increased yield and fruit number per tree for each of 3 consecutive years (P ≤ 0.05). The number of commercially valuable largesize fruit also increased significantly with yield increases (r2 = 0.88). Sodium tetraborate applied foliarly to `Hass' avocado (Persea americana Mill.) trees at the cauliflower stage of inflorescence development (elongation of inflorescence secondary axes, pollen and ovule development) increased the number of pollen tubes reaching the ovule, ovule viability and cumulative yield (P ≤ 0.05). Additional examples are presented.

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SNP markers reveal relationships between fruit paternity, fruit quality and distance from a cross-pollen source in avocado orchards

Scientific Reports ◽

10.1038/s41598-021-99394-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Wiebke Kämper ◽

Steven M. Ogbourne ◽

David Hawkes ◽

Stephen J. Trueman

Keyword(s):

Nutritional Quality ◽

Management Strategies ◽

Fruit Size ◽

Fruit Production ◽

Snp Markers ◽

Pollination Services ◽

Cross Pollination ◽

Pollen Transport ◽

Avocado Fruit ◽

Hass Avocado

AbstractCross-pollination can improve fruit yield, fruit size and nutritional quality of many food crops. However, we rarely understand what proportions of the crop result from self- or cross-pollination, how cross-pollination affects crop quality, and how far pollen is transported by pollinators. Management strategies to improve pollination services are consequently not optimal for many crops. We utilised a series of SNP markers, unique for each cultivar of avocado, to quantify proportions of self- and cross-paternity in fruit of Hass avocado at increasing distances from cross-pollen sources. We assessed whether distance from a cross-pollen source determined the proportions of self-pollinated and cross-pollinated fruit, and evaluated how self- and cross-paternity affected fruit size and nutritional quality. Avocado fruit production resulted from both self- and cross-pollination in cultivar Hass in Queensland, Australia. Cross-pollination levels decreased with increasing distance from a cross-pollen source, from 63% in the row adjacent to another cultivar to 25% in the middle of a single-cultivar block, suggesting that pollen transport was limited across orchard rows. Limited pollen transport did not affect fruit size or quality in Hass avocados as xenia effects of a Shepard polliniser on size and nutritional quality were minor.

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Genotypic and Chemical Influences on Fruit Growth of Tomato

HortScience ◽

10.21273/hortsci.25.10.1255 ◽

1990 ◽

Vol 25 (10) ◽

pp. 1255-1257 ◽

Cited By ~ 2

Author(s):

Henry R. Owen ◽

Louis H. Aung

Keyword(s):

Linear Regression ◽

Lycopersicon Esculentum ◽

Gibberellic Acid ◽

Foliar Application ◽

Fruit Size ◽

Fruit Shape ◽

Fruit Growth ◽

New Yorker ◽

Maturation Rate ◽

Fruit Diameter

A relationship between ovary size at anthesis and final fruit diameter of 12 tomato (Lycopersicon esculentum Mill.) cultivars with a range of fruit sizes, shapes, and maturation rates was determined. `Fireball', `Michigan/Ohio Hybrid', and `New Yorker' produced nonfasciated, spherical fruits of intermediate maturation rate and showed a significantly higher correlation between ovary diameter at anthesis and final fruit diameter than `Small Fry', `Roma VF', `Early Cascade', `Campbell 1327', or `Ponderosa'. A linear regression of final fruit diameter at maturity on ovary diameter at anthesis of the cultivars was highly significant (r2 = 0.92**; ÿ = 22.5X - 0.3). Continuous root application of 0.01 μm BA to seedlings of `Fireball' significantly delayed anthesis. A single foliar application of 0.37 mM NOA to `Fireball' plants at the appearance of the first inflorescence significantly increased ovary diameter on the first inflorescence, but decreased ovary diameter on the second inflorescence. Treatment with NOA altered final fruit shape but not final fruit diameter. Single foliar applications of 0.1 mM GA stimulated stem and peduncle elongation but did not affect fruit size. Chemical names used: ß-naphthoxyacetic acid (NOA), N6-benzylaminopurine (BA), gibberellic acid, (GA).

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