Relationship Between Climate and Provenance Variation in Eucalyptus Camaldulensis Dehnh.

1995 ◽  
Vol 22 (3) ◽  
pp. 453 ◽  
Author(s):  
A Gibson ◽  
EP Bachelard ◽  
KT Hubick

The morphology and physiology of Eucalyptus camaldulensis seedlings grown from seed collected from two locations in the dry tropics, two in the humid tropics and two in semi-arid Northern Australia were compared in phytotron growth cabinets under well-watered and water-limited conditions and diurnal temperature ranges of 30-25 and 22-15�C. Seedlings from the two locations in each climate resembled each other more closely than they resembled seedlings from the other climates across the range of conditions tested. When water-limited, seedlings from the dry tropical and semi-arid climates had a higher allocation of dry matter to roots than seedlings from the humid tropics. However, those from the dry tropics shed their lower leaves and initiated small-leaved axillary shoots while those from the semi-arid climate retained their leaves and did not produce axillary shoots. In contrast, seedlings from the humid tropics responded by reduced gas (CO2 and H2O) exchange without changes in morphology or allocation of dry matter. These responses are appropriate for growth in each climate and are consistent with observations made on wild trees in the field, on trees in plantations overseas and also with data from seedlings grown in earlier glasshouse experiments.

2014 ◽  
Vol 153 (2) ◽  
pp. 371-380 ◽  
Author(s):  
A. L. A. NEVES ◽  
R. D. SANTOS ◽  
L. G. R. PEREIRA ◽  
G. F. OLIVEIRA ◽  
C. B. SCHERER ◽  
...  

SUMMARYForage sorghum (FS) (Sorghum bicolor(L.) Moench) is a key feed source for ruminants owing to its high yield and drought tolerance. The present paper assessed the agronomic characteristics, silage quality, intake and digestibility of five new Brazilian sorghum cultivars (BRS Ponta Negra variety, BRS 655 hybrid, BR 601 hybrid, BRS 506 variety and BRS 610 hybrid). Forages were grown (randomized complete block design) in a typical Brazilian north-eastern semi-arid climate, irrigated with 267 mm water, harvested as plants reached the soft dough stage of grain maturity and ensiled under laboratory and farm conditions. Apparent digestibility of the silages was determined using 25 Santa Inês lambs. BRS 506 outperformed the other cultivars in dry matter (DM) and digestible DM yields/ha. BRS 506 exhibited the lowest neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents and the highestin vitrodry matter digestibility (IVDMD) of the cultivars examined. BRS 655 produced the lowest level of lactic acid and the highest pH and ammonia-N concentration. There was no difference in intake or digestibility of DM among cultivars. Silages produced from BRS Ponta Negra resulted in higher crude protein (CP) intake than BRS 655. Silages made from BRS 506 and BRS Ponta Negra resulted in a greater digestibility of CP than those produced from BRS 655. Intake of NDF in silages generated from BRS Ponta Negra and BRS 610 was higher than that found in other cultivars. Although an average Brazilian North-eastern FS exhibited similar characteristics to other cultivars grown in dry regions around the world, the results indicated that BRS 506 had a yield advantage and higher nutritive value under Brazilian semi-arid conditions as compared to the other cultivars examined.


Heredity ◽  
2002 ◽  
Vol 88 (5) ◽  
pp. 402-412 ◽  
Author(s):  
P A Butcher ◽  
A Otero ◽  
M W Mcdonald ◽  
G F Moran

1989 ◽  
Vol 40 (3) ◽  
pp. 573 ◽  
Author(s):  
RL McCown ◽  
BH Wall

In the semi-arid tropics, accumulated shed leaf of certain pasture legumes can provide highly nutritious feed for cattle in the dry season. Previous papers in this series have dealt with the fungal spoilage of leaf of Caribbean stylo in response to dew and unseasonal rainfall and the threat to acceptability by cattle. This paper focuses on the effects of varying degrees of moulding and leaching on dry matter digestibility of leaf of this legume. Uniform leaf material of high digestibility was exposed at six locations during the dry season and samples retrieved at 4-weekly intervals. From initial values of 75%. in vitro digestibility dropped to as low as 50%. Degree of moulding, as indicated by a quantitative index of discoloration, accounted for about 80�/o of loss. Moulding was much more important than leaching. This latter finding in the winter-dry tropics contrasts with previous findings in the summer-dry Mediterranean climate.


1992 ◽  
Vol 32 (2) ◽  
pp. 149 ◽  
Author(s):  
RM Sullivan ◽  
PK O'Rourke ◽  
DJ Robertson ◽  
D Cooke

Cow reproductive rates, mortalities and liveweights, and steer growth rates from a herd of 500 Bos indicus - Bos taurus cross cows and their progeny were recorded over a period of 4 years from June 1981. The cattle grazed native pastures and were not supplemented. Cows which had a calf of more than 100 kg in June were allocated to 2 treatments: weaned and unweaned. Where the calf weighed less than this amount, cows were allocated to a separate 'young calf group. In the year following branding, weaning increased (P<0.05) conception rate from 73.9 to 93.8% and reduced (P<0.05) cow mortality rate from 14.1 to 4.5%, relative to the unweaned group. On average, weaned cows conceived 3 months earlier (P<0.05) than the other 2 groups, in November, and 27% of weaned cows subsequently calved out of season the following year, compared to 4% of the other groups. This affected subsequent weaning management by increasing the number of calves too young to wean in June. Weaned steers grew at a reduced (P<0.05) rate during the first year post-weaning. Despite compensatory gain in the next 2 years, they were still 26 kg lighter (P<0.05) than their unweaned counterparts at 3.5 years of age.


1994 ◽  
Vol 45 (8) ◽  
pp. 1439 ◽  
Author(s):  
PJ Thorburn ◽  
LJ Mensforth ◽  
GR Walker

Measurements of naturally occurring stable isotopes of hydrogen (2H) and oxygen (18O) were used to determine the importance of creek waters to river red gums (Eucalyptus camaldulensis Dehnh., Myrtaceae) on the banks of creeks in the semi-arid and saline Chowilla floodplain region of South Australia. The 2H and 18O concentrations of water sampled from trees were significantly different from those of the creek water, indicating that, generally, trees were not obtaining all their water from the creek. This was found even in trees overlying highly saline groundwater. Thus, saline groundwater and/or soil water were important water sources for the trees studied. The results indicated that the water relations of these trees are complex, and the trees may be less affected by changes in creek flow and/or salinity than was previously anticipated.


Zootaxa ◽  
2021 ◽  
Vol 5082 (1) ◽  
pp. 30-40
Author(s):  
PAUL M. HUTCHINSON ◽  
PETER G. ALLSOPP

The genus Pseudholophylla Blackburn, 1911 (Coleoptera: Scarabaeidae: Melolonthinae: Melolonthini) is reviewed and males of a sixth species, P. hurai new species, are described and differentiated from males of the remaining species. The only known female, of P. lepidoptera Blackburn, 1912, is described and illustrated. The genus occurs across northern Australia in areas of savanna, hot semi-arid or hot desert and specimens are collected rarely.  


1998 ◽  
Vol 49 (2) ◽  
pp. 179 ◽  
Author(s):  
A. K. Borrell ◽  
A. L. Garside ◽  
S. Fukai ◽  
D. J. Reid

Production of flooded direct-seeded rice (Oryza sativa L.) in semi-arid tropical regions of northern Australia would be enhanced by increasing the efficiency of fertiliser nitrogen (N) use. Short-statured and early-maturing genotypes have replaced the taller and later genotypes in northern Australia, and they may respond differently to N. This paper reports the results of 4 experiments comparing the response of 3 rice genotypes differing in maturity and stature to 5 rates of applied nitrogen (0, 70, 140, 210, and 280 kg/ha) over 4 seasons (2 wet and 2 dry seasons) in the Burdekin River Irrigation Area, northern Australia. Grain yield varied among seasons and was negatively correlated with average daily mean temperature during the 30-day period before anthesis. The response of yield to N fertilisation was generally higher in the dry season. Panicle number was correlated with grain yield in both seasons, yet responded to N fertilisation only in the dry season. In 3 of 4 experiments, grain yield responded to the application of up to 70 kg N/ha, yielding about 750 g/m2. In only 1 dry season experiment did grain yield respond to the application of 140 kg N/ha, yielding about 930 g/m2. In this experiment, the response of grain yield to N rate also varied among genotypes such that yield in the early-maturing genotypes (Newbonnet and Lemont) was more responsive to N rates above 70 kg/ha than in the late-maturing genotype (Starbonnet). Of the 3 genotypes examined, highest yields were attained in Newbonnet (early-maturing, medium-statured) by combining high total dry matter production with high harvest index, indicating that this plant type may have an advantage in northern Australia. Yields in Lemont (early-maturing, short-statured) and Starbonnet (late-maturing, tall-statured) were limited by dry matter production and harvest index, respectively. There is some evidence that increased dry matter production in Newbonnet compared with Lemont was related to increased stem length. The evidence linking high harvest index with increased earliness in Newbonnet compared with Starbonnet is less compelling.


2004 ◽  
Vol 53 (1-6) ◽  
pp. 182-186
Author(s):  
H. S. Ginwal ◽  
Pradip Kumar ◽  
V. K. Sharma ◽  
A. K. Mandal

Abstract Results of a provenance trial of Eucalyptus camaldulensis Dehnh. laid out in 2001 at Seothi (30° N Lat., 76° E Long. and 250 m altitude) Haryana, a semi-arid region of India are reported and discussed. Six seed sources from Australia viz. Laura River, Emu Creek, Degrey River, Wiluna, Kennedy River, Morehead River were evaluated from nursery stage (3 months) to field performance (2 year). Two sources viz. E.tereticornis (Helenvele, Qld) and FRI-4 a local seed source were used as control (check material). Significant differences between the seed sources at nursery stage were observed for collar diameter (P < 0.05) and number of leaves (P < 0.01). At age 2 years, significant differences between the seed sources (P < 0.05) were observed for height and field survival. The two seed sources viz. Emu Creek Petford, QLD and Laura river, QLD ranked first and second for height and survival at this age. Results indicate that genetic differences exist between the sources of E. camaldulensis. None of the traits assessed (viz. height, collar diameter, number of leaves, number of branches and survival) was found to correlate with any of the geographical coordinates of the site (latitude, longitude and altitude). There were fair differences between phenotypic and genotypic coefficient of variability. Heritability values were fairly high for height and clear bole length in comparison to collar diameter, number of branches and survival. The relative performance of these provenances was fairly consistent throughout the period of observation. The two sources viz. Laura river, QLD and Emu Creek Petford, QLD are recommended for potential source for plantation programme under semi-arid conditions.


1975 ◽  
Vol 15 (75) ◽  
pp. 493 ◽  
Author(s):  
RC Gutteridge ◽  
PC Whiteman

Four accessions of the semi-arid shrub legume Psoralea eriantha were evaluated under three six and nine week cutting regimes for 72 weeks in pots in the glasshouse. Total yield increased in all accessions with increasing intervals between cutting. Yield in the three week cutting interval was only 36 per cent of the yield in the nine week cutting interval. The one erect accession, though giving the highest average yield, also suffered the highest mortality under the frequent defoliation. The other accessions suffered little mortality. Defoliation frequency affected root and stubble weights and these were closely correlated with total dry matter yields. Frequent defoliation also markedly reduced the number of primary and secondary shoots. It is suggested that survival under grazing may be more important than a higher yielding ability.


1975 ◽  
Vol 15 (76) ◽  
pp. 655 ◽  
Author(s):  
LA Edye ◽  
JB Field ◽  
DF Cameron

Fifteen accessions, comprising Stylosanthes guyanensis (1 ), ., hamata (5), S. humilis (2), S. subsericea (5) and interspecific hybrids (2), were compared when grown in swards with the grass Urochloa mosambicensis at three sites in the dry tropics of Queensland with an average growing season ranging from 11.5 to 22.0 weeks per annum. The swards were harvested at 6-weekly intervals during the growing season at a height of 7.6 cm. Over the three years of the trial, S. hamata CPI 38842 (cv. Verano) was superior in dry matter yield over all sites to the other accessions, including the two S. humilis cultivars cv. Paterson and cv. Lawson. Nodulation problems prevented an adequate comparison of four other S, hamata accessions except at 'Fanning River', where CPI 40264A and 40268 nodulated effectively and were as productive as cv. Verano. All S. hamata accessions perennated but gave lower pod yields and seedling regeneration than S. humilis cultivars. In vitro digestibility of the S. hamata accessions was lower than S. humilis in May but higher in September. Although S. subsericea accessions nodulated readily at all sites, their performance was site-sensitive and all but one accession failed to perennate.


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