Response of wheat cultivars to dates of sowing under dryland conditions

1983 ◽  
Vol 101 (3) ◽  
pp. 727-733 ◽  
Author(s):  
R. De ◽  
G. Saran ◽  
B. B. Turkhede ◽  
R. B. Lal ◽  
R. K. Singh ◽  
...  

SUMMARYField experiments made for 4 years between 1976–7 and 1979–80 in a semi-arid environment of north-west India showed that the productivity of dryland unirrigated wheat can be increased considerably by adjusting the date of sowing to conducive atmospheric temperatures. Sowing in the middle of November when daily mean temperatures ranged between 19 and 21 °C produced yields ranging between 2·6and 3·5t/ha (averaged over the 4 years) compared with 1·4–3·3 t/ha obtained from the crop sown by mid-October when the daily mean temperature ranged between 24 and 26 °C. The tall cultivar C 306, a derivative of winter x spring wheat cross, could withstand sowing at higher temperatures (mid-October) more than the spring wheats. High temperatures prevailing during the seedling stage of spring wheats shortened their vegetative growth and initiated early differentiation. Night temperatures above 13 °C coupled with day temperatures of 33–35 °C in the last fortnight of October adversely affected the tillering of spring wheats sown on 15 October and produced smaller spikes with few fertile spikelets.

1998 ◽  
Vol 25 (5) ◽  
pp. 547 ◽  
Author(s):  
Nick Dexter

The two parameters believed to influence habitat utilisation by feral pigs and wild boar (Sus scrofa) are protection from high temperatures and distribution of food. However, whether there is an interaction between these parameters is unknown. To examine the influence of high temperature on habitat utilisation, the use of four rangeland habitats (shrubland, woodland, riverine woodland, and ephemeral swamps) by feral pigs in north-west New South Wales, Australia, was measured by radio-telemetry during and after a drought. In each habitat, protection from high temperature was indexed once by vegetation cover, at three strata, while over the course of the study, food distribution was indexed by estimating pasture biomass in each habitat. Riverine woodland provided the most shelter from high temperature, followed by woodland, shrubland and ephemeral swamps. On average, ephemeral swamps had the highest pasture biomass, followed by riverine woodland, shrubland and woodland. The amount of pasture in each habitat increased after the drought but changed at different rates. During autumn, spring and summer feral pigs preferred riverine woodland but in winter shrubland was preferred. Multivariate regression indicated that habitat utilisation was significantly influenced by pasture biomass in shrubland and mean maximum temperature in the study area. The results suggest that feral pigs are restricted by high temperatures to more shady habitats during hot weather but when the constraint of high temperature is relaxed they distribute themselves more according to the availability of food.


2006 ◽  
Vol 138 (5) ◽  
pp. 638-646 ◽  
Author(s):  
Ian L. Wise ◽  
Robert J. Lamb ◽  
Ronald I.H. McKenzie ◽  
Jay W. Whistlecraft

AbstractThe Canadian spring wheat (Triticum aestivum L.; Poaceae) cultivar ‘Superb’ was less susceptible to damage by Hessian fly, Mayetiola destructor (Say), than the spring wheat cultivars ‘AC Barrie’, ‘AC Foremost’, ‘McKenzie’, ‘AC Domain’, and ‘Glenlea’ in Manitoba. The partial resistance of ‘Superb’ was similar, at the seedling stage, to that of ‘Guard’, which possesses the resistance gene H18. Females laid eggs readily on all cultivars, providing no evidence for antixenosis, but few larvae developed on seedlings of ‘Superb’ and ‘Guard’, showing that antibiosis against larvae is the mechanism of resistance in these seedlings. In the field, where infestation of spring wheat takes place about 4 weeks after the seedling stage, ‘Guard’ continued to show high levels of resistance, but ‘Superb’ was less resistant, although still more resistant than highly susceptible cultivars. Infested stems of ‘Superb’ and ‘Nordic’ were less likely to break than infested stems of other cultivars, showing that these two cultivars are partially tolerant to infestation. Infested stems of ‘Guard’ and other cultivars showed high levels of stem breakage and are intolerant. Yield losses due to infestation by Hessian fly were mostly caused by the breakage and falling over of infested stems, which prevented the seeds on these stems from being harvested. Infested stems of all susceptible cultivars that remained standing at harvest had lower seed masses and fewer seeds per spike than uninfested stems, which contributed to yield loss. ‘Grandin’, a parent of ‘Superb’, is the probable source of resistance in ‘Superb’, but the pedigree of ‘Grandin’ provides no clue as to the gene(s) involved. The partial antibiosis and tolerance expressed by ‘Superb’ is sufficient to reduce losses to Hessian fly by 65% in comparison with a susceptible cultivar such as ‘AC Barrie’. ‘Superb’ is the first Canadian spring wheat cultivar identified to have an agronomically useful level of resistance to Hessian fly.


2015 ◽  
Vol 66 (6) ◽  
pp. 566 ◽  
Author(s):  
T. M. McBeath ◽  
V. V. S. R. Gupta ◽  
R. S. Llewellyn ◽  
C. W. Davoren ◽  
A. M. Whitbread

In low-rainfall environments, a high frequency of cereal crops has been favoured for optimising productivity and risk. However, cereals at high intensity often lead to declining water-use efficiency and increasing inputs to cope with emergent nutritional, disease and weed problems. The value of including breaks in the cropping sequence can involve a high level of uncertainty in low-rainfall areas where non-cereal crops are more risky and profitability is largely determined by the subsequent benefit to cereal productivity. In this study, we aimed to improve understanding of the magnitude and primary source of break benefits such as nutrition, water and disease management in a low-rainfall environment where a high level of within-field soil variability can also contribute to uncertainty about the value of breaks. In on-farm field experiments near Karoonda in the South Australian Mallee, breaks were grown in 2009 or 2010 on four distinct soil types across a dune–swale catena. The effect of these breaks on subsequent cereal production was measured for up to 3 years. In addition, the effect of breaks on nutrition and water available, along with disease infection in subsequent cereal crops, was explored and actual yields were compared with nitrogen and water-limited potential yields. Consistent cumulative benefits to subsequent cereal crops of at least 1 t ha–1 after 3 years accrue from breaks grown on the different soil types. The inclusion of breaks had beneficial effects on the cycling and supply of nutrients along with some short-term impacts on infection by Rhizoctonia solani AG8 in subsequent cereals, whereas there were no conclusive effects of breaks on the supply of water to subsequent crops. This study suggests that the inclusion of both legume and brassica breaks is likely to be beneficial to subsequent cereal production where nitrogen is a factor limiting productivity in low-rainfall, semi-arid environments.


2021 ◽  
Vol 2 (1) ◽  
pp. 11-17
Author(s):  
Hina Kanwal ◽  
Abida Kausar ◽  
Rashda Naheed ◽  
Noreen Akhtar ◽  
Fozia Farhat ◽  
...  

Salt stress impact was appraised on different antioxidative enzymes, MDA and H2O2 in ten spring wheat cultivars i.e., S-24, Lasani, Fsd-2008, Saher-2006, Inqlab-91, AARI-10, P.B-18, S.H-20, M.P-65, and G.A-20 when salinity applied at the seedling stage. The wheat cultivars were grown under saline (150 mM) and non-saline regimes (0 mM) in pots filled with sand. Diverse response in all wheat cultivars was observed in different studied attributes. Saline stress markedly decline SOD, CAT and POD conc. in different wheat cultivars. While some cultivars (S-24, Lasani, AARI-10 and GA-20) showed increase in these attributes under saline condition as compared to control. MDA and H2O2 content were increased in different wheat cultivars due to imposition of salt stress at the seedling stage. Whereas decrease in some cultivars was recorded in these attributes under saline regime than in non-saline conditions. Of all wheat cultivars, S-24, Lasani, AARI-10 and GA-20 showed high antioxidative activity, less lipid peroxidation and H2O2 content in plant shoot when salt stress applied at the seedling stage. On the basis of higher antioxidative activity and less MDA and H2O2 content, these four cultivars (S-24, Lasani, AARI-10 and GA-20) could be categorized as salt tolerant as compared to others


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