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  • Author or Editor: Julian C. Crane x
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Abstract

Pronounced vegetative apical dominance in pistachio was exhibited by sparse lateral branching and by response to conventional pruning. This dominance necessitates a pruning procedure different from other deciduous fruit and nut species. Marked apical dominance also occurred both in the patterns of fruit set in the inflorescence as a whole and in the individual branches composing it. The percentage of fruit set was highest in the apical portion of the inflorescence and generally decreased to the proximal portion. Similarly, although only 8% of the flowers on the branches of the inflorescence occupied a terminal position, 60% of the total fruit produced were terminal.

Open Access

Abstract

Neither abscisic acid (ABA) levels in developing kernels nor in the developing inflorescence buds themselves were found to be related to abscission of inflorescence buds and consequent alternate bearing in pistachio (Pistacia vera L.).

Open Access
Authors: and

Abstract

Radial trunk growth measured by the Verner dendrometer was reduced markedly due to competition for assimilates and water by greatly stimulated fruit growth resulting from the application of 2,4-D. These responses were accompanied by reduced water tension within the 2,4-D-treated trees, as indicated by less diurnal trunk shrinkage than that which occurred in control trees.

Open Access

Abstract

During the first 5 years of production, significantly greater yields of pistachios were obtained with the ‘Kerman’ on seedlings identified as Pistacia atlantica Desf. than with ‘Kerman’ on seedlings of P. palaestina Boiss., P. terebinthus L., or P. vera L. The least productive combination was ‘Kerman’ on P. vera, the species that produces the edible pistachio nut. Weight per nut, percent blank nuts, and percent nuts with split shells did not differ significantly among the rootstock combinations.

Open Access

Abstract

The pistachio (Pistacia vera L.), characteristically a biennial bearer, produces its most extensive shoot growth in years of heavy crop production. Whereas levels of total sugars in bark and wood of bearing and nonbearing branches were similar throughout the year, starch levels tended generally to be higher in nonbearing than in bearing branches. Consequently, nonbearing branches one year gave rise to heavy crops the next and, beacuse of greater quantities of reserve foods, also produced extensive shoot growth. Bearing branches of that same year, .however, produced few or no nuts the next and, because of lesser quantities of reserve foods, produced markedly less shoot growth. No relationship between total nitrogen level and shoot growth or fruiting was evident.

Open Access
Authors: and

Abstract

Concentrations of several mineral elements in leaflets of Pistacia vera L. cv. Kerman, did not differ significantly with leaflet position. Thus, leaflets may be used instead of whole leaves in leaf sampling. Analyses of leaflets indicated that N, P, and Zn concn were relatively high initially. They then dropped rapidly during leaf expansion, reaching a steady state in early summer. Manganese increased from an initially low level and then remained fairly constant. Potassium, Mg, Cl, and B behaved similarly to Mn, but reached constant levels later in the season. Leaves from bearing branches were lower in N and P, but higher in K than leaves from nonbearing branches. It is recommended, in determining mineral element status, that leaves from nonbearing branches be sampled during the month prior to harvest, as most elements are then at a steady state.

Open Access

Abstract

Movement of 14C-photosynthates in bearing and nonbearing branches of pistachio (Pistacia vera L.) was examined during the period of inflorescence bud abscission. Most of the 14C transported from leaves accumulated in developing nuts. Inflorescence buds on defruited trees accumulated twice as much 14C-photosynthate as those on fruiting trees. Inflorescence buds competed poorly against the developing fruit for photosynthate and this might be responsible for inflorescence bud abscission and resultant alternate bearing.

Open Access

Abstract

Hastened fruit maturation following MH application to apricot trees was found to be associated with MH-induced seed abortion. The time and degree to which premature abscission of seedless fruits occurred was related to time of resumption of shoot growth and to crop load. Fruits in which the seeds aborted early in the season grew like those containing seeds when competition between their growth and vegetative growth was reduced to a minimum.

Open Access

Abstract

Intact phloem appeared essential for basipetal translocation or sink-induced acropetal movement of 12C and 14C-ethephon [(2-chlorethyl) phosphonic acid]. A source-to-sink movement of 14C was indicated by the mobilization of radioactivity by fruits distal to a treated leaf. The amount of 14C mobilized by fruits was modified somewhat by their pattern of vascular connections. Over a period of time 14C diffused freely from bark tissue into wood. However, there was no indication that it was translocated in the transpiration stream. The radioactivity in extracts of fig fruits and branches was extracted and confirmed to be 14C-ethephon.

Open Access

Abstract

In the pistachio cv. Kerman an average of 26% of the fruits contain no seeds or only poorly developed ones at maturity. A study of aberrations revealed; a) pollen tubes sometimes entered the embryo sacs at the chalazal end (the pistachio is chalazogamous), which may result in eventual degeneration of endosperm or zygote nuclei; b) frequent degeneration of zygote (or egg) or young endosperm nuclei from unknown causes; c) occurrence of a brown spot on the funiculus of many young seeds in some years, the necrosis usually spreading to the embryo sac; d) and hypertrophy of nucellar cells in some older seeds was frequently accompanied by proliferation of other nucellar cells, both limiting development of embryo and endoperm. In cv. Bronte a frequent aberration is protrusion of endosperm or embryo through a greatly distended endostome.

Open Access