Effects of fruit load on flower bud initiation and development in peach

Summary This study aims to quantify the effects of fruit crop-load on flowering and to determine the relationships between flowering and phloem sap carbohydrate and nitrogen content fractions from budding to dormancy in ‘Zincal 5’ nectarine. Fruit load significantly reduced the number of flowers per tree both indirectly, by reducing the number of shoots per tree and the number of nodes per shoot, and directly, by reducing the number of floral buds per node. The intensity of the response depended on the number of fruits developed per tree. Trees that kept all fruits up to senescence flowered 35% less than trees thinned by hand to 40% of fruits at pit hardening, and 55% less than trees completely thinned in bloom by hand. Trees that kept all fruits had significantly lower glucose and sorbitol contents in the phloem sap of mixed branches up to harvest date and full vegetative growth, respectively, but no significant relationships were found between the concentrations of these carbohydrates and flowering intensity in the following Spring. Sucrose and fructose did not show any significant difference in regard to crop-load. In fibrous roots, starch content was not related to fruit load up to dormancy, indicating that starch content is not associated with flower bud induction and differentiation. The nitrate-nitrogen fraction was significantly higher, and the ammonium-nitrogen fraction was significantly lower, in trees that tended to flower less, suggesting some disturbance in nitrate reduction in these trees.

[1]  D. M. Reid,et al.  The supply of gibberellins from the root to the shoot , 1964, Planta.

[2]  A. Samach,et al.  ASPECTS OF FLOWERING IN FRUIT TREES , 2004 .

[3]  G. B. Leite,et al.  Trophic control of bud break in peach (Prunus persica) trees: a possible role of hexoses. , 2004, Tree physiology.

[4]  A. Martínez‐Fuentes,et al.  RESTRICTIONS ON THE EXOGENOUS CONTROL OF FLOWERING IN CITRUS , 2004 .

[5]  J. Syvertsen,et al.  Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees. , 2003, Tree physiology.

[6]  R. Byers,et al.  Partial Flower Thinning Increases Shoot Growth, Fruit Size, and Subsequent Flower Formation of Peach , 2002 .

[7]  M. Agustí,et al.  Plant Growth Regulators in Citriculture: World Current Uses , 2000 .

[8]  E. Goldschmidt,et al.  GIBBERELLINS AND FLOWERING IN CITRUS AND OTHER FRUIT TREES: A CRITICAL ANALYSIS , 1998 .

[9]  M. Talón,et al.  Defoliation increases fruit abscission and reduces carbohydrate levels in developing fruits and woody tissues of Citrus unshiu , 1995 .

[10]  R. Vandijk,et al.  Determination of nitrate in vegetables by continuous flow: interlaboratory study. , 1994 .

[11]  M. Raigón,et al.  Determination of available nitrogen (nitric and ammoniacal) in soils by flow injection analysis , 1992 .

[12]  D. H. Carbaugh,et al.  The influence of bloom thinning and GA3 sprays on flower bud numbers and distribution in peach trees , 1990 .

[13]  C. Lovatt,et al.  Demonstration of ammonia accumulation and toxicity in avocado leaves during water-deficit stress , 1987 .

[14]  G. R. Edwards.  AMMONIA, ARGININE, POLYAMINES AND FLOWER INITIATION IN APPLE , 1986 .

[15]  A. Schaffer,et al.  A role for carbohydrate levels in the control of flowering in citrus , 1985 .

[16]  R. Pharis,et al.  Gibberellins and Reproductive Development in Seed Plants , 1985 .

[17]  E. Goldschmidt,et al.  Alternate Bearing in Fruit Trees , 1982 .

[18]  E. Goldschmidt,et al.  Alternate bearing in citrus and ways of control. , 1982 .

[19]  S. P. Monselise.  Understanding the plant processes as a basis for successful growth regulation in citrus. , 1980 .

[20]  H. Jonkers.  Biennial bearing in apple and pear: A literature survey , 1979 .

[21]  G. V. Hoad.  THE ROLE OF SEED DERIVED HORMONES IN THE CONTROL OF FLOWERING IN APPLE , 1978 .

[22]  G. Moss.  Effect of fruit on flowering in relation to biennial bearing in sweet orange (Citrus sinensis) , 1971 .

[23]  J. D. Quinlan,et al.  The Influence of Shoot Competition on Fruit Retention and Cropping of Apple Trees , 1971 .

[24]  J. Crane,et al.  Gibberellin-Induced Inhibition of Bud Development in Some Species of Prunus , 1960, Science.