The Time of Floral Induction in the Olive

Abstract

<jats:p>GA<jats:sub>3</jats:sub> scaffold injections applied between May and November to nonbearing olive <jats:italic>(Olea europea</jats:italic> L.) trees inhibited flowering the following year, increased shoot width when applied in May, June, and July, and increased inflorescence length when applied in November and February. Fruit removal and seed destruction were effective in improving the return bloom in `Manzanillo' olives when done before endocarp sclerification. Depending on-the year, endocarp sclerification takes place 7 to 8 weeks after full bloom (AFB), usually about 1 July. Fruit removal had no effect on flowering when done after this time. Scaffold injection of paclobutrazol applied to bearing trees between May and September did not affect flowering the following year. The results of our research supports the hypothesis that olive flower induction occurs around the time of endocarp sclerification. Chemical names used: gibberellic acid (GA<jats:sub>3</jats:sub>), (2RS,3RS)-1-(4-chlorophenyl)-4-dimethyl-2-1,2-4-triazol-1-yl) pentan-3-ol(paclobutrazol).</jats:p>

Relationship between reproductive behavior and new shoot development in 5-year-old branches of olive trees (Olea europaea L.)

“…Those results are consistent with other (Cimato and Fiorino 1986;Fernández-Escobar et al 1992;Ramos et al 2000;Stutte and Martin 1986) and with the alternate bearing phenomenon (Costes et al 2006;Monselise and Goldschmidt 1982;Obeso 2002). For all bearing conditions, however, reproductive development was independent of both shoot length and origin.…”

“…4 Percentage of subsequently reproductive shoots according to shoot type for shoots formed during bearing (a, b) and non-bearing (c, d) years. Each column represents the mean and standard error of the percentage of reproductive shoots of each shoot type per 5-year branch for 18 branches (three/tree for six trees) in 2003 and 12 (three/tree for four trees) in 2004. n total number of new shoots observed but also to a lack of reproductive development at the existing sites, consistent with the proposed inhibition of reproductive bud induction by the presence of growing fruits and seeds (Fernández-Escobar et al 1992;Stutte and Martin 1986).…”

“…However assimilate level and morphology only partially determine alternate bearing behavior, which is influenced by a complex combination of regulatory and nutritional factors still not fully understood (Costes et al 2006;Lavee 1996). A major limitation to flowering in the following season is the abundant presence of fruits (Almeida 1940;Cimato and Fiorino 1986;Ramos et al 2000), and, more specifically, compounds originating in the developing seed which appear to inhibit floral induction (Fernández-Escobar et al 1992;Stutte and Martin 1986). Studies of olive buds to determine the factors which regulate olive flower induction, initiation and differentiation (De la Rosa et al 2000;Fabbri and Alerci 1999;Pinney and Polito 1990) also tend, however, in line with the above-mentioned experimental approach, to choose predefined individual shoots, potentially biasing the results and losing an overall view of tree behavior.…”

Morphological, histological and ultrastructural changes in the olive pistil during flowering

“…Research on olive floral biology has been principally horticultural in orientation, mainly addressing (1) the physiological and environmental factors that influence the flowering time (Lavee 1986;Fernández-Escobar et al 1992;Dos Santos Ramos 2000) and (2) variability in the flower phenology phases among cultivars (Barranco and Rallo 1984;Barranco et al 1994;Rallo et al 2005). The few studies of pistil morphology have described the pistil features at anthesis (Serrano et al 2008) or considered only ovary structure and processes related to fertilization success (Ciampolini et al 1983;Rapoport 2001;Reale et al 2006), but without systematically examining sequential developmental changes.…”

The use of phenological data to calculate chilling units in Olea europaea L. in relation to the onset of reproduction

“…During the last decade, the conviction that environmental factors during the winter play a role in flower induction and subsequent initiation (Badr and Hartmann 1972;Fornaciari et al 1998;Hackett and Hartmann 1967;Hartmann and Whisler 1975) has given way to the concept that, in the olive, low temperatures are only needed to break dormancy in previously initiated buds, as occurs in other fruit tree species (Pinney and Polito 1990;Rallo and Martin 1991;Fernandez-Escobar et al 1992).…”