Factors affecting ‘Hass’ avocado fruit size: Carbohydrate, abscisic acid and isoprenoid metabolism in normal and phenotypically small fruit

2000 ◽  
Vol 109 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Evelyn W. Richings ◽  
Ryan F. Cripps ◽  
A. Keith Cowan
HortScience ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 257-261 ◽  
Author(s):  
Samuel Salazar-García ◽  
Luis E. Cossio-Vargas ◽  
Isidro J.L. González-Durán ◽  
Carol J. Lovatt

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wiebke Kämper ◽  
Steven M. Ogbourne ◽  
David Hawkes ◽  
Stephen J. Trueman

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.


Horticulturae ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 34
Author(s):  
Christopher Menzel

Five strawberry (Fragaria × ananassa Duch.) cultivars were grown in Queensland, Australia to determine whether higher temperatures affect production. Transplants were planted on 29 April and data collected on growth, marketable yield, fruit weight and the incidence of small fruit less than 12 g until 28 October. Additional data were collected on fruit soluble solids content (SSC) and titratable acidity (TA) from 16 September to 28 October. Minimum temperatures were 2 °C to 4 °C higher than the long-term averages from 1965 to 1990. Changes in marketable yield followed a dose-logistic pattern (p < 0.001, R2s = 0.99). There was a strong negative relationship between fruit weight (marketable) and the average daily mean temperature in the four or seven weeks before harvest from 29 July to 28 October (p < 0.001, R2s = 0.90). There were no significant relationships between SSC and TA, and temperatures in the eight days before harvest from 16 September to 28 October (p > 0.05). The plants continued to produce a marketable crop towards the end of the season, but the fruit were small and more expensive to harvest. Higher temperatures in the future are likely to affect the economics of strawberry production in subtropical locations.


1965 ◽  
Vol 43 (1) ◽  
pp. 137-146
Author(s):  
L. Butler

Fruit weights taken from two F2's of 1500 plants indicated that the genes d p o s Lc dil and suf all affect fruit weight. The recessive alleles, except suf and Lc, were associated with small fruit size. The data were analyzed to determine whether this association was the result of linkage or pleiotropic effects. The major effect occurred in the o region, which is some 44 units from the centromere of chromosome 2. The o gene makes the genes oval or pear-shaped instead of spherical, and it is shown that when the locule wall of a spherical fruit and an oval fruit are composed of the same number of cells, the spherical fruit is always heavier. Since cell number is the inherited unit of fruit size, then o is always associated with small size. A gene controlling number of locules, which affects fruit size, is also located in this section of the chromosome. The genes d and s, which are at opposite ends of the present linkage map, both appear to be linked with fruit size genes. It is suggested that these size genes lie in the hetero-chromatin which is adjacent to both ends of the linkage map. The genes dil and suf, which were produced by radiation of the same variety, appear to have pleiotropic effects on fruit size; suf increasing, and dil decreasing fruit size.


2010 ◽  
pp. 47-54 ◽  
Author(s):  
J. Burdon ◽  
N. Lallu ◽  
G. Haynes ◽  
P. Pidakala ◽  
D. Billing ◽  
...  

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 996-1005 ◽  
Author(s):  
Ana L. Valencia ◽  
Pilar M. Gil ◽  
Bernardo A. Latorre ◽  
I. Marlene Rosales

Several species of the Botryosphaeriaceae family have been associated with branch canker, dieback, and stem end rot in avocado (Persea americana Mill.). In Chile, the incidence of diseases affecting the avocado tree increased from 2011 to 2016, which coincided with a severe drought that affected avocado production. Moreover, distant countries importing avocados from Chile also reported an increase of stem end rot of ripe avocados. Therefore, the aims of this study were to identify the pathogen species associated with branch canker, dieback, and stem end rot of avocado in Chile and to study their pathogenicity. This study was conducted between 2015 and 2016 in ‘Hass’ avocado orchards located in the main avocado-producing regions in Chile. A diverse collection of fungal species was recovered from both necrotic woody tissue and necrotic tissue on harvested ripe fruit. On the basis of morphology and phylogenetic analyses of the internal transcribed spacer region (ITS1-5.8S-ITS2) and the translation elongation factor 1-α (TEF1-α) gene, eight species in the Botryosphaeriaceae family were identified: Diplodia mutila, D. pseudoseriata, D. seriata, Dothiorella iberica, Lasiodiplodia theobromae, Neofusicoccum australe, N. nonquaesitum, and N. parvum. For each of these species, pathogenicity studies were conducted on 1-year-old healthy Hass avocado plants. All isolates produced brown gum exudate and caused necrosis in the vascular system 3 weeks after inoculation. N. nonquaesitum, N. parvum, and D. pseudoseriata were the most virulent species. Necrotic lesions and cavities with white mycelia near the peduncle union were observed on Hass avocado fruit inoculated postharvest. L. theobromae, N. australe, and N. parvum were significantly more virulent than the other tested species in the Botryosphaeriaceae family. This study identified and characterized the pathogenicity of Botryosphaeriaceae species in Chile, which will prove useful to future research on these pathogens directed at establishing effective control strategies in avocado.


Plant Disease ◽  
2016 ◽  
Vol 100 (9) ◽  
pp. 1951-1951 ◽  
Author(s):  
C. Torres ◽  
R. Camps ◽  
R. Aguirre ◽  
X. Besoain

2020 ◽  
Vol 14 ◽  
Author(s):  
Verônica Pellizzaro ◽  
Mônica Satie Omura ◽  
Jean Carlo Braubraz de Paula ◽  
Felipe Favoretto Furlan ◽  
Lúcia Sadayo Assari Takahashi

Physalis peruviana L., a small fruit belonging to the Solanaceae family, is known for the high vitamins A and C, iron, and phosphorus content. As it presents numerous opportunities for adding value to family producers, it has been gaining space in the consumer market. Characteristics such as fruit size and seed extraction methods can interfere with the physiological potential of the seeds. Thus, the objectives of this study were to evaluate the relationship between fruit size and physiological quality of Physalis seeds and to establish an effective method for the extraction of its seeds. The experiment was conducted at the Phytotechnics Laboratory of the State University of Londrina, using a completely randomized design in a 3×2 factorial scheme, with 4 replications of 50 seeds. The factors consisted of three fruit sizes (small, medium, and large) and two extraction methods (manual and mechanical). The averages obtained were compared using the Tukey test (p ≤ 0.05). After 28 days of germination, the following evaluations were made: percentage of germination, first germination count, germination speed index, length, and dry mass of seedlings. The physiological potential of the seeds was influenced by the size of the fruits. The method of manual seed extraction proved to be superior and more efficient than the mechanical method.


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