Effect of pistil receptivity, pollen mixtures, and pollen application distances on fruit set of pistachios (Pistacia vera)

Abstract

This study was carried out at the pistachio (Pistacia vera) orchards of Ceylanpınar State Farm, Turkey. The cultivar 'Siirt' and Male 13 were used in the experiments. The aim of the study was to investigate the effect of pistil receptivity, pollen mixtures, and pollen application distances on fruit set using artificial pollination in pistachios. To determine the receptivity of female flowers, anthesis was accepted as day 0, and then one application was carried out on 0, 2, and 4 days after anthesis; and repeated applications were done on 0+2, 0+4, 2+4, and 0+2+4 days, separately. Pollen and wheat flour was mixed to obtain 1%, 5%, 10%, 50%, and 100% pollen mixture, and these pollen mixtures were sprayed from 25, 50, and 100 cm distances from the inflorescence clusters with a small hand sprayer. Thus, fruit set was determined for the applications. Different pollen mixtures were applied to a microscope slide, covered with Vaseline, from three different application distances to determine the number of pollen grains per unit area by artificial pollination. The number of pollen grains per unit area was counted under a light microscope and calculated per 1 mm 2 . Finally, adequate pollen numbers to pollinate a flower were determined. The results indicate that for optimum fruit production of pistachio, 5% and 50% pollen mixtures should be sprayed at a distance of 100 cm at 0 and 4 days after anthesis. The adequate number of pollen grains to pollinate a flower was calculated as 14 or 15 pollen grains per flower in pistachio. Increased number of pollen per stigma area would cause excessive flower abscission after a certain point, and this could be the cause of low fruit set in pistachios.

Dust Interferes with Pollen–Stigma Interaction and Fruit Set in Pistachio Pistacia vera cv. Kerman

“…The amount of viable pollen loaded on the stigma is the first step in pollination (Wilcock and Neiland, 2002). Acar and Eti (2008) reported 14 or 15 pollen grains per stigma is adequate for pollination in pistachio. On germination, the pollen tube grows the length of the style to the micropyle, the opening in the ovule's outer layer.…”

From flower to fruit: ecological and evolutionary implications of abiotic and biotic factors affecting Juniperus thurifera L. cone development

“…However, several pollination experiments have found a reduction in reproductive success and several mechanisms have been proposed to explain that decrease (Young and Young 1992). For example, large pollen loads on flowers may have negative effects on pollen tube growth (Cruzan et al 1986;Acar and Eti 2008). Our second pollination experiment showed that this was not the cause of lower fruit set because fruits developing from hand-pollinated flowers had proportionally more grown pollen tubes than fruits from natural-pollinated flowers.…”

Biodiversity and ecosystem services in a tropical smallholder landscape in Madagascar

“…Successful pollination is depending on a range of factors during pollen application. The amount of manually applied pollen can affect the fruit set (Acar & Eti, 2008). The optimal pollen amount needed for fertilization can depend on environmental conditions (Peet & Bartholemew, 1996) and species (Acar & Eti, 2008;Janse & Verhaegh, 1993).…”

“…The amount of manually applied pollen can affect the fruit set (Acar & Eti, 2008). The optimal pollen amount needed for fertilization can depend on environmental conditions (Peet & Bartholemew, 1996) and species (Acar & Eti, 2008;Janse & Verhaegh, 1993). In natural pollination, pollen is applied gradually in contrast to hand pollination, where great pollen amounts are applied at once (Fazzino et al, 2011).…”

“…In natural pollination, pollen is applied gradually in contrast to hand pollination, where great pollen amounts are applied at once (Fazzino et al, 2011). A sudden application of excessive amounts of pollen can cause stigma clogging, leading to decomposition of pollen in the stigma, which directly ends in flower abortion (Polito et al, 1998), as described for pistachio (Acar & Eti, 2008) and walnut (W. H. Krueger, 2000;McGranahan & Voyiatzis, 1994). To achieve the desired proportion of pollen, it can be mixed with a diluent such as water, wheat flour or talc, which also facilitates its distribution and reduces adherence during hand pollination (Acar & Eti, 2008;Vaknin et al, 1999;.…”