Fruit Set and Seed Number from Self- and Cross-pollinated Highbush (4x) and Rabbiteye (6x) Blueberries1

Seed counts from self- and cross-pollinated highbush blueberry cultivars suggested that fertility in both mating systems is under similar genetic control. Viable seed set following selfing and outcrossing was inversely correlated with zygotic levels of inbreeding, and percentage of seed abortion in both crosses showed a positive association with zygotic F values. Among six genotypes, cross- and self-fertility were highly correlated. Fluorescent microscopy revealed no differences in the frequency of self and foreign pollen tube growth into ovules. Variation in self- and cross-fertility among these cultivars was attributed to differences in zygotic levels of homozygosity and cumulative expression of recessive mutations that promote seed abortion.

Section: Discussionmentioning

confidence: 50%

The Consequences of Inbreeding on Fertility in Vaccinium corymbosum L.

Krebs

Hancock

1988

“…The results of this study are consistent with previous pollination experiments with highbush, lowbush (V. angustifolium Ait. ), and rabbiteye (V. ashei Reade) blueberries, in which increasing seed number per berry improves fruit set, increases berry size, and decreases the days from pollination to ripening (Aalders and Hall, 1961;Bailey, 1938;Coville, 1921;Darrow, 1941;El-Agamy et al, 1981;Gupton, 1984;Jackson et al, 1972;Knight and Scott, 1964;Krebs and Handcock, 1988;Meader and Darrow, 1947;Moore et al, 1972;Rabaey and Luby, 1988;Vander Kloet and Lyrene, 1987;White and Clark, 1938). Two trends are clear from the literature, however: a) The cultivated Vaccinium spp.…”

Section: R Esults and Discussionmentioning

confidence: 99%

Pollen Source Influences Fruiting of ‘Sharpblue’ Blueberry

Lyrene

1989

The effects of cross-pollination, self-pollination, and mixed (self plus cross) pollination of ‘Sharpblue’ blueberry (primarily V. corymbosum) were studied. The pollen for cross-pollination came from V. corymbosum clones ‘O’Neal’ and ‘FL 2-1’. Self-pollination resulted in 37% fruit set, compared to 74% to 91% set for the other pollination treatments. The number of well-developed seeds per matured berry averaged 3.5 for self-pollination, 13.0 for mixed pollination, and 24.4 for cross-pollination. The number of days from pollination to ripe fruit was highly and negatively correlated with berry seed number, regardless of the pollen source. Mixed pollinations delayed ripening an average of 7 days compared to cross-pollination, and self-pollination delayed ripening by an additional 13 days over mixed pollination.

“…Mainland et al (11) found that T ifblue' fruit set averaged only 16% when plants were caged to prevent cross-pollination, compared with 78% set when openpollinated. Similarly, El-Agamy et al (6) found low self compatibility among most rabbiteye cultivars in Florida. Fruit set for open-pollinated plants ranged from 75% for 'Southland' (10) to 12.8% for 'Tifblue' rabbiteye cultivars in Florida (5).…”

mentioning

confidence: 90%

“…Yield is a function of many factors, including flower bud number, flower number per bud, and fruit size (8); however, the percentage of fruit set may be important in Florida and similar areas, where plants may receive less than optimum chill units (2). Many factors affect fruit set of rabbiteye blueberry, including cross-compatibility (6), presence and activity of pollinators (5), water stress (1,2), plant nutrition (2), growth regulators (4,11), and chill unit accumulation (2). Rabbiteye blueberries are generally self-unfruitful and set a very low percentage of flowers when not adequately cross-pollinated (6,13).…”

mentioning

confidence: 99%

“…Many factors affect fruit set of rabbiteye blueberry, including cross-compatibility (6), presence and activity of pollinators (5), water stress (1,2), plant nutrition (2), growth regulators (4,11), and chill unit accumulation (2). Rabbiteye blueberries are generally self-unfruitful and set a very low percentage of flowers when not adequately cross-pollinated (6,13). Mainland et al (11) found that T ifblue' fruit set averaged only 16% when plants were caged to prevent cross-pollination, compared with 78% set when openpollinated.…”

mentioning

confidence: 99%

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Flower Position, Growth Regulators, and Fruit Set of Rabbiteye Blueberries

Davies

1986

Seasonal patterns of fruit drop and the influence of flower position and bloom date on fruit set were studied for ‘Woodard’, ‘Bluegem’, and ‘Tifblue’ rabbiteye blueberries (Vaccinium ashei Reade). The pattern of fruit drop was similar for the 3 cultivars, with most the drop occurring within 3 to 4 weeks of full bloom. Fruit drop was most severe for ‘Tifblue’, which set only 21% to 27% of its flowers, compared with 46% to 60% for ‘Woodard’ and 53.5% to 55% for ‘Bluegem’. Position of flowering shoots in the bush and time of flower opening had no consistent effect on the percentage set, although flowers in a terminal position on the shoot generally set a higher percentage of fruit than those in a lateral position for ‘Woodard’. Spray application of gibberellic acid (GA) or (2,4-dichlorophenoxy)-acetic acid (2,4–D) at various times during bloom did not affect yields. The percentage of fruit set was poorly correlated with yields within a season for ‘Woodard’ and ‘Bluegem’, indicating that flower number is also an important determinant of yields. However, poor fruit set for ‘Tifblue’ was associated with low yields.