Cyclic pollen production in Cedrus deodara

2009 ◽  
Vol 22 (2) ◽  
pp. 53-61 ◽  
Author(s):  
Vinod Prasad Khanduri ◽  
Chandra Mohan Sharma
2017 ◽  
Vol 01 (02) ◽  
Author(s):  
Parvan Parvanov ◽  
Dinko Dinkov
Keyword(s):  

1972 ◽  
Vol 52 (4) ◽  
pp. 569-574 ◽  
Author(s):  
K. C. YEUNG ◽  
E. N. LARTER

A study of the pollen production properties of three hexaploid triticale strains (Triticale hexaploide Lart.) showed that their anther length was significantly greater than that of wheat anthers (Triticum aestivum L. em Thell.) and the estimated number of pollen grains per anther ranged from 15,000 to 21,000. In comparison, a total of 8000 grains per anther was estimated for wheat, cult Manitou. Eighty-nine percent anther extrusion occurred in triticale cult Rosner, while Manitou averaged 70% anther extrusion. The period of anthesis of triticale varied according to strain but generally was of longer duration than in Manitou and thereby promoted outcrossing. Using a triticale strain carrying a dominant marker gene, 50% seed-set was obtained at a distance of 12 m leeward of the pollen source; however, a small percentage was still obtained at a distance of 30 m. It would appear from the limited number of triticales used in this study that a wide range of variability exists within this species in its pollen production and disseminating properties. With appropriate selection pressures, strains with an outbreeding habit could be developed for the purpose of hybrid seed production.


Author(s):  
Yingchao Ji ◽  
Guohua Li ◽  
Chenggang Zhou ◽  
Shuyan Yin

Abstract Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.


2016 ◽  
Vol 39 (2) ◽  
pp. 101-110
Author(s):  
R. Verma

A study was conducted to understand the floristic diversity along an altitudinal gradient with elevations varying from 1800-2400m above msl in Lakadmandi beat of Kalatop Khajjiar Wildlife Sanctuary in district Chamba, Himachal Pradesh during 2011. Total number of plant species was 81 belonging to 52 families and 76 genera. The dominant families were Asteraceae, Rosaceae, Pinaceae and Polygonaceae. The number of trees species was 6, 6 and 10 with the dominance of Quercus leucotrichophora, Cedrus deodara and Cedrus deodara at 1800-2000m, 2000-2200m and 2200-2400m elevation ranges respectively. The number of shrub species was 16, 13 and 23 with the dominance of Quercus leucotrichophora sapling, Sarcococca saligna and Sarcococca saligna at 1800-2000m, 2000-2200m and 2200-2400m elevations respectively. The number of herb species was 46, 46 and 58 at 1800-2000m, 2000-2200m and 2200-2400m elevation ranges respectively. On the basis of Importance Value Index (IVI), Valeriana jatamansii was the dominant herb at 2000-2200m and 2200-2400m elevation ranges respectively. The distribution pattern of most of plant species was contiguous at all altitudinal ranges. Index of diversity for herb species in these elevational ranges was 3.420, 3.568 and 3.250. Out of 40 medicinal plant species recorded from the area, 3 species i.e. Paris polyphylla, Podophyllum hexandrum and Taxus wallichiana fall in the category of threatened plants. The better conservation of natural resources can be done through promotion of community based conservation, ex-situ conservation through tissue culture, developing cultivation technologies and nurseries of medicinal plants and conducting of regular training on the procedure of medicinal plants collection and processing among the end users.


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