M. Abo-Youssef, A. El Sabagh, G. Abo-Gendy and A. Mohamed
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Yin, C., Gan, L., Denny, N.G., Zhou, X. & Xia, K. (2007). Decreases paniclederived indole-3-acetic acid reduces gibberellin A1 level in the uppermost internode, causing panicle enclosure in male sterile rice Zhenshan 97A. J. Exp. Bot., 58(10): 2441-2449.
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Reference genes are generally used as endogenous normalization factor for relative quantification of target genes in quantitative real-time PCR (qRT-PCR). The present work aimed at identifying suitable reference genes for normalization of qRT-PCR data in tissues of Eucalyptus tereticornis. The expression levels of housekeeping genes like Actin (EtAct2), Isocitrate dehy - drogenase (EtIDH), ribosomal RNA (Et18s rRNA), SAND family protein (EtSAND), Histone protein (EtH2B), α-Tubulin (EtTUB), and eukaryotic initiation factor (EteIF4B) were studied to characterize their normalization stability in different tissues including young leaves, internodes, developing and mature xylem. The expression level of these genes was analyzed using different algorithms like geNorm, NormFinder and Best- Keeper. Among the seven reference genes analyzed, EtAct2 was expressed with less variance and was found to be the most stable reference gene across different tissues using all the three programs, while the least stable gene identified was EtH2B. Further, the normalization efficiency of the reference genes were assessed to predict the expression levels of three primary cell wall specific cellulose synthase transcripts (EtCesAs) in E. tereticornis tissues. The relative expression of EtCesA4, EtCesA5 and EtCesA6 was determined to be 3-19 fold higher in leaf and internode tissues when compared to developing and mature xylem tissues. This study will allow accurate normalization of qRT-PCR experiments across different tissues in E. tereticornis for future genomic research in this tropical eucalypt species.
This study was conducted to investigate the effect of various horticultural substrates (compost, peat-coconut, peat TS1, flower soil, lowmoor peat) and a foliar spray of chlormequat (at a concentration of 1380 mg dm-3) on the growth and flowering of the marigold cultivars belonging to two species: Tagetes erecta - ʻMarvel Mixtureʼ and ʻTaishan Orangeʼ, and Tagetes patula - ʻDurango Redʼ and ʻBonanza Flameʼ. The obtained results show that the plants grown in peat TS1 and peat-coconut were taller, had longer internodes and leaves, and thicker stems than the plants grown in the other substrates. Chlormequat significantly reduced the height of ʻMarvel Mixtureʼ (in peat TS1), ʻTaishan Orangeʼ (in lowmoor peat) and ‘Bonanza Flameʼ (in peat-coconut). The use of chlormequat also accelerated the development of flower heads in ʻTaishan Orangeʼ (in lowmoor peat).
The present study has described a simple protocol for efficient plant regeneration of Asparagus densiflorus ‘Sprengeri’ and ‘Myriocladus’ using single-node spear explants, and indirect organogenesis via callogenesis induced on internode explants. The results showed that the genotypes ‘Sprengeri’ and ‘Myriocladus’ regenerated to complete plants via nodal cultures and callus tissue, but the plant regeneration response was higher in secondary explants on MS medium with NAA + kinetin (1+1 mg dm-3) after transfer onto a multiplication medium with IAA+BAP (1+4 mg dm-3), and then onto a rooting medium supplemented with IBA (10 mg dm-3) or NAA + kinetin (1+1 mg dm-3). Primary explants of both cultivars showed high regenerative potential (via the callus stage) on MS medium with IAA+BAP. The cultivar Sprengeri also regenerated via somatic embryogenesis. Both kinds of ‘Meyeri’ explants have a morphogenetic potential for the formation of shoots, which, however, were not capable of rooting. This confirms that the explant, genotype and culture medium are determining factors in the in vitro plant regeneration system.
Effects of different pH sprays on the efficiency of prohexadione-Ca in sweet cherry trees
In 2003 and 2004, young ‘Kordia’ sweet cherry trees were sprayed with prohexadione-Ca (Pro-Ca) to control tree growth and stimulate flower bud setting. A rate of 200 mg Pro-Ca l-1 × 2 dissolved in various pH-buffered (6.0-4.5) aqueous solutions was used. Regardless of the acidity of the spray solution applied, the trees treated with Pro-Ca were characterised by reduced shoot and internode length, greater number of shoots (2003) and increased total shoot extension (2004) relative to the control. In both years, Pro-Ca applied in a pH-4.5 buffer solution contributed to an increase of flower bud clusters on current-season shoots. However, there were no significant differences among Pro-Ca/pH treatments either in the vegetative or generative characteristics studied. Two years after Pro-Ca application, no residual effects were found in the studied tree characteristics.
G. Prabhakara Rao, K. Suma, J. Madhavan and Y. A. Varghese
Para rubber (Hevea brasiliensis), a native of the Amazon forests of South America, is the chief source of natural rubber in the world. With the objective of broadening the original gene pool collected by Sir Henry Wickham in 1876, the International Rubber Research and Development Board (IRRDB) made a large collection of wild germplasm from Acre, Rondonia and Mato Grosso states of Brazil in 1981, which was distributed to various member countries including India for conservation and evaluation. In the present study, variability was assessed in a set of 195 Hevea accessions belonging to the wild gene pool in India, using 22 characterization descriptors and eight quantitative growth characters in the juvenile stage. The Shannon-Weaver diversity indices worked out for each of the 22 qualitative traits indicated a high level of diversity in the collection. The range of variation for quantitative traits viz., plant height (0.43 to 3.16 m), basal diameter (0.81 to 2.52 cm), number of whorls (1.23 to 5.48), inter-node length (4.11 to 45.26 cm), number of leaves (11.44 to 91.26), single leaf area (80.22 to 223.57 cm2), total leaf area (2356.00 to 14660.50 cm2) and leaf area index (0.24 to 1.47), also represented wide variability in the collection. The accessions were ranked for overall performance and top 10% were selected for early growth vigour. The high level of variability observed in this germplasm indicates its potential use in crop improvement programmes and for broadening the genetic base of Hevea.
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of mepiquat chloride on elongation of cotton (Gossypium hirsutum L.) internode is associated with low concentration of gibberellic acid. Plant Science 225: 15-23. DOI: 10.1016/j.plantsci.2014.05.005.
Vranova E., Inze D., Van Brensegem F. 2002. Signal transduction during oxidative stress. J. Exp. Bot. 53(372): 1227-1236. DOI: 10.1093/jexbot/53.372.1227.
Yamazaki J., Ohashi A., Hashimoto Y., Negishi E., Kumagai S., Kubo T., et al. 2003. Effects of high light and low temperature during harsh winter on needle photodamage of Abies
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Carvalho S., Heuvelink E., Cascais R., Van Kooten O., 2002. Effect of day and night temperature on internode and stem length in chrysanthemum: is everything explained by DIF? Ann. Bot. 90: 111-118.
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