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Yongsheng Liu

Xenia (including metaxenia) is described as the direct or immediate pollen effect on the size, shape, color, developmental timing, and chemical composition of seeds and fruits ( Denney, 1992 ). It has been proven that xenia is widespread and

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Qin Yang, Yan Fu, Yalan Liu, Tingting Zhang, Shu Peng, and Jie Deng

As early as 1868, Darwin devoted six pages to describe “the direct or immediate action of the male element on the mother form” in his book The Variation ( Liu, 2008 ); a phenomenon that now we call xenia. Xenia refers to the direct effect of the

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Guanxing Hu, Chao Gao, Xiaoming Fan, Wenfang Gong, and Deyi Yuan

Xenia is defined as the effect of foreign pollen on the development of fruit tissue. It involves the interaction between a nuclear gene from the male gamete and either two polar nuclear genes from the endosperm or one nuclear gene from the egg

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James O. Denney and George C. Martin

Xenia and metaxenia are phenomena dealing with the effects that pollen from different sources have on certain characteristics exhibited by seeds and fruits in a variety of species. A review of dictionaries, textbooks, and the scientific literature reveals that there is widespread confusion with regard to the nature of these phenomena and how they are to be distinguished. This discussion will attempt to clarify the boundary between these related phenomena by examining both the origins of the terms and our present understanding of the metabolism and anatomy involved. From this perspective, we contend that xenia applies to pollen effects as exhibited in the syngamous parts of ovules, that is, the embryo and endosperm only. Metaxenia applies to such effects found in any structure beyond the embryo and endosperm, this is, in tissues which derive wholly from mother plant material. Metaxenia then encompasses effects found in seed parts such as the nucellus and testa as well as those found in carpels and accessory tissue.

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James O. Denney and George C. Martin

Xenia and metaxenia are phenomena dealing with the effects that pollen from different sources have on certain characteristics exhibited by seeds and fruits in a variety of species. A review of dictionaries, textbooks, and the scientific literature reveals that there is widespread confusion with regard to the nature of these phenomena and how they are to be distinguished. This discussion will attempt to clarify the boundary between these related phenomena by examining both the origins of the terms and our present understanding of the metabolism and anatomy involved. From this perspective, we contend that xenia applies to pollen effects as exhibited in the syngamous parts of ovules, that is, the embryo and endosperm only. Metaxenia applies to such effects found in any structure beyond the embryo and endosperm, this is, in tissues which derive wholly from mother plant material. Metaxenia then encompasses effects found in seed parts such as the nucellus and testa as well as those found in carpels and accessory tissue.

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James O. Denney

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Creighton L. Gupton and James M. Spiers

To determine the effects of pollen source on blueberry production, we made a partial diallel set of crosses involving seven rabbiteye (Vaccinium ashei Reade) and seven southern highbush (SH; V. corymbosum L.) parents. Pollination of rabbiteye blueberry flowers with SH pollen reduced fruit set, seeds per berry, and berry weight and increased fruit development period (FDP) compared to pollination with rabbiteye pollen. Pollination of SH flowers with rabbiteye pollen resulted in about the same fruit set and FDP but fewer seeds per berry and slightly lower berry weight compared to intraspecific pollination. Self-pollination significantly decreased the number of seeds per berry and berry weight and increased FDP in SH. Pollination of rabbiteye and SH flowers with mixed pollen produced the same results as intraspecific pollination. Using `Tifblue' and `Baldwin' (rabbiteye) as the pollen parent significantly increased FDP in rabbiteye blueberry. Using `Georgiagem' and `Cape Fear' as pollen parents produced the longest FDP, and using `O'Neal' and `Gulfcoast' produced the shortest FDP in SH blueberry. The heaviest berries were produced by using `Blue Ridge', `O'Neal', and `Gulfcoast' (SH) as pollen parents on SH females. These results suggest that xenia possibly could be used to increase yield and reduce FDP in blueberry.

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Lihang Xie, Lixin Niu, Yanlong Zhang, Min Jin, Duo Ji, and Xiaoxiao Zhang

responsible for the xenia, whereas Liu (2008) proposed that the signal to trigger the xenia effect may be mRNAs. Previous studies have described that oil content in rapeseed ( Wang et al., 2010 ) and maize ( Weingartner et al., 2004 ) could be affected by

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Xenia Wolff

Chayote (Sechium edule Swartz) is a minor vegetable crop gaining in popularity in the U.S., but with only scant cultural information on it available. The soil pH and water requirements-and the effects of various soil amendments on plant productivity were detemined in three separate greenhouse pot studies. Chayote plants were grown in either one of eight soil pH levels (5.0 to 6.5), were watered at one of three rates (1.3, 2.5, or 5.0 cm per week), or were planted in one of 16 soil amendment treatments (Oliver silt loam soil or a 1 soil: 1 peat moss (v/v) mix amended with inorganic N-P-K fertilizer, 25 or 50 kg cow or rabbit manure/ha, or 12.5 or 25 kg chicken manure/ha). Data on date of germination, plant height, single and total leaf areas, total plant and separate plant part fresh and dry weights, and presence of flowers were collected. Greatest plant productivity was achieved with a soil pH range of 5.6 to 6.5, a watering rate of 2.5 cm per week, and with several of the soil amendment treatments.

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Shyi-kuan Ou, J. Benton Storey, and Tommy E. Thompson

Preharvest germination (viviparity) can be a problem with nuts of pecan [Carya illinoinensis (Wangenh.) K. Koch]. Two southern-adapted cultivars (`Cherokee' and `Wichita') and one northern-adapted cultivar (`Johnson') were paternal parents in controlled crosses with the maternal parent `Wichita'. `Wichita' × `Johnson' seed took much longer to germinate than seed from either the `Wichita' × `Cherokee' cross or the `Wichita' self, therefore indicating that pollen source may influence germination characteristics.