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145 Chandola A., Thapliyal, J. P. (1973) Effect of photoperiod on thyroid function of spotted munia, Lonchura punctulata . Gen. Comp. Endocrinol. 20 , 214

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( Hordeum vulgare L.) under different photoperiod regimes. Theor. Appl. Genet. , 94 , 612–618. Bedő Z. Effects of loci on chromosomes 2(2H) and 7(5H) on developmental patterns

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Karsai, I., Mészáros, K., Szűcs, P., Hayes, P. M., Láng, L., Bedő, Z. (1999): Effects of loci determining photoperiod sensitivity (Ppd-H1) and vernalization response (Sh2) on agronomic traits in the Dicktoo x

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Beales, J., Turner, A., Griffiths, S., Snape, J.W., Laurie, D.A. 2007. Apseudo-response regulator is misexpressed in the photoperiod insensitive Ppd-D1a mutant of wheat ( Triticum aestivum L.). Theor. Appl

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Acta Veterinaria Hungarica
Authors: Vera Faigl, Mónika Keresztes, Alíz Márton, Hedvig Fébel, Margit Kulcsár, Sándor Nagy, Sándor Cseh, László Solti, and Gyula Huszenicza

Seasonal differences in the resumption of postpartum ovarian activity, milk production and periparturient metabolic status were investigated in lactating non-suckling dairy Awassi sheep in two consecutive experiments. In Experiment 1, autumn-lambing (AL, n = 27) and spring-lambing (SL, n = 37) ewes were investigated. Ovarian activity was monitored by means of individual progesterone (P4) profiles from day 5 to day 100 post partum. Most of the AL dams (89%) ovulated till day 35 after parturition and became cyclic thereafter. Incidence of persistent corpus luteum (CLP) and short luteal phases (sCL) was frequent (18% and 29%, respectively) among non-conceiving dams. In contrast, only 24% of the SL ewes ovulated before day 35. P4 levels during the luteal phase were lower in cyclic animals, and the cycle was longer in SL than in AL animals. No CLP or sCL was detected in the spring-lambing group, and 61% of SL ewes remained acyclic till the end of the trial. Lactation length was significantly longer in SL dams than in AL ewes (P = 0.008). According to the plasma metabolites (BHB, NEFA) and metabolic hormones (insulin, IGF-I, thyroxine) examined, negative energy balance did not appear in any of the animals. However, seasonal differences were seen in IGF-I and thyroxine levels, which were higher in the SL dams. In Experiment 2, influence of additional lighting was studied in autumn-lambing ewes. The long-day photoperiod (LD, n = 23) group was exposed to artificial light from sunset till midnight (approx. 16 h light/8 h dark) from some weeks before the expected date of delivery in mid-September until the end of December. The control group (n = 25) experienced only natural daylength. The first postpartum ovulation tended to occur later in the LD animals than in the controls (P = 0.047). The lactation of the LD group tended to be longer (P = 0.061). NEFA, BHB, insulin, IGF-I and thyroxine levels did not differ between the groups. Conclusions: (i) The ovarian function of the Awassi population is seasonal under temperate continental climate conditions. (ii) The first postpartum ovulation of non-suckling, autumn-lambing dams may occur very early, even before the completion of uterine involution. (iii) Additional artificial lighting may delay the time of first postpartum ovulation in AL ewes. (iv) Postpartum negative energy balance is unlikely to occur in dairy Awassi ewes even in high-producing intensive systems.

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Bani, A., Tabarsa, M., Falahatkar, B., Banan, A. (2009) Effects of different photoperiods on growth, stress and haematological parameters in juvenile great sturgeon Huso huso . Aqua. Res. 40 , 1899

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. 1997 43 211 216 Muguruma, F., Goto, S. G., Numata, H., Shiga, S. (2010) Effect of photoperiod on clock gene expression

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Biologia Futura
Authors: Muhammad Saad, Helen Mary, Umar Amjid, Ghulam Shabir, Kashif Aslam, Shahid Masood Shah, and Abdul Rehman Khan

Tartary buckwheat, known for its rich source of health beneficial secondary metabolites, is cultivated in many areas of the world. Among different environmental factors, photoperiod strongly influence its growth, flowering time, and ultimately the yield. In this context, epigenetics could contribute significantly in the regulation of plant response against changing environment. Therefore, with the aim to study the involvement of DNA methylation in photoperiod mediated plant response, genome-wide DNA methylation analysis was performed in two accessions (A1 and A2) of Tartary buckwheat using three photoperiodic treatments, i.e., 10-hr light/day (T1), 12-hr light/day (T2), and 14-hr light/day (T3). Flowering time and plant fresh weight data revealed that accessions A1 and A2 prefer T1 and T2 treatments, respectively. Total DNA methylation ratio increased with the increase in photoperiod in accession A1 but decreased under same conditions in accession A2. Full methylation increased significantly while intensive decrease in hemimethylation was noted from T2 to T3 in A1, whereas full methylation strongly increased and hemimethylation strongly decreased from T1 to T2 in A2. Overall, the DNA methylation events appeared more frequently than demethylation events. This study reports for the first time an accession-/genotype specific pattern of shift in the DNA methylation under different photoperiodic treatments that will pave the way toward identification of specific genes involved in the regulation of plant response against photoperiodic stress.

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Ninety-nine wheat cultivars from six different agro-climatic zones of India were analyzed for the Vrn-1, Vrn-2, Vrn-B3, Vrn-4 and Ppd-D1 composition with DNA sequenced based allele specific or linked markers for the above-mentioned genes. A majority of the germplasm carried the dominant Vrn-A1a allele alone or in combination with Vrn-B1 and Vrn-D1. The three dominant genes were cumulatively present in 30 cultivars among all the zones, whereas double dominant combination, Vrn- A1/Vrn-B1 was identified in 18 cultivars, Vrn-A1/Vrn-D1 in 6 cvs and Vrn-B1/Vrn-D1 in 16 cvs. The combination of the dominant alleles of all three genes was most frequent in cvs of Northern Western Plains Zone. Northern Hill Zone had vrn-B1 and vrn-D1 alleles in higher proportions compared to the dominant alleles Vrn-B1 and Vrn-D1 indicating successful spring/winter wheat cross breeding. All of the cvs had the recessive Vrn-B3 allele. Most of the cvs had photoperiod insensitive allele in all the zones and only 9% cvs possessed the photoperiod sensitive allele (b) of the Ppd-D1 gene. This information will be useful in selecting parental lines for crossing to maximize diversity at these loci and for future molecular marker assisted breeding for cultivar improvement.

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The baya weaver Ploceus philippinus, despite its purely tropical origin and tropical/subtropical distribution, exhibits all features of a typically photoperiodic species. The onset of reproduction in this species is triggered by increasing daylength and breeding is terminated by the development of distinct photorefractory phase. In order to ascertain the involvement of androgens in the development of photorefractoriness the long day response of birds was tested after a prior exposure to varied doses of testosterone. Testosterone treatment accelerated the onset of photorefractoriness as judged from the gonadal status, LH-dependent yellow plumage and testosterone-dependent beak pigmentation. While gonadal development and yellow plumage occurred in the control birds due to the stimulatory long photoperiod, the testosterone administered birds failed to show such developments. These findings indicate that testosterone might impair the higher photoresponding mechanisms resulting in the development of photorefractoriness.

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