Comparison of Factors Influencing Fruit Size in Large-Fruited and Small-Fruited Clones of Strawberry1

Abstract

The relative decline in fruit size from primary to secondary to tertiary positions on the inflorescence of large-fruited clones was much greater than for small-fruited clones. Large-fruited clones produced fruit with more achenes and larger achenes than did small-fruited clones. Fruit weight was positively correlated with total achenes per fruit, developed achenes per fruit, mean weight of total and developed achenes, and fruit weight per developed achene. These results lead to the conclusion that fruit size differences among strawberry clones are due to the combined effects of developed achene number, developed achene size, differential activity of achenes in producing growth hormones and differential sensitivity of receptacular tissue in responding to growth hormones.

Relationship Between Achene Number, Achene Density, and Berry Fresh Weight in Strawberry

“…Each of these values was the smallest observed for the corresponding genotype grown in the hill system. Thus, the mean number of achenes/cm2 was very high compared to pre- vious studies (2,4,7). This difference probably was due to both genotypic and environmental differences between previous studies and this study.…”

“…Thus, in the matted row, genotypic variation in berry weight and, perhaps, yield were more dependent on total number of achenes per berry than the NA/C. Moore et al (4) found that large-fruited clones had more achenes per berry and produced more receptacle tissue per achene than small-fruited clones. However, Olsen et al (7) found that differences in berry weight of two genotypes could not be accounted for by differences in the total number of achenes per berry.…”

Yield Component Analysis of ‘Benton’ and OR-US 4356 Strawberries

“…The difference in berry size between 'Benton' and OR-US 4356 cannot be attrib uted to number of achenes/berry, as there was no significant difference either year (Ta ble 2). As others conclude (12), however, fruit size differences among strawberry clones vary not only with achene number but with size of achenes and their differential activity in relation to growth hormones.…”

“…In areas where temperatures are cool for 2-3 weeks after bloom, apples attain type most regularly (4, 7, 8, 10, 11). Rootstock, strain, crop density, and flower position also affect length/diameter (L/D) ra tios of 'Delicious' fruit (9,12,15). High postbloom temperatures apparently affect the balance of endogenous auxins, gibberellins, and cytokinins, resulting in the cessation of cell division and elongation and ultimately causing flattened fruit (9,12).…”

“…Rootstock, strain, crop density, and flower position also affect length/diameter (L/D) ra tios of 'Delicious' fruit (9,12,15). High postbloom temperatures apparently affect the balance of endogenous auxins, gibberellins, and cytokinins, resulting in the cessation of cell division and elongation and ultimately causing flattened fruit (9,12). Exogenous applications of cytokinins and gibberellins stimulate additional cell division and elon gation in apple fruitlets, resulting in im proved type of mature fruit (1, 2, 3, 5, 6,11,13,16,17).…”