scholarly journals Threshold Tolerance of New Genotypes of Pennisetum glaucum (L.) R. Br. to Salinity and Drought

Agronomy ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 230 ◽  
Author(s):  
Kristina Toderich ◽  
Elena Shuyskaya ◽  
Zulfira Rakhmankulova ◽  
Roman Bukarev ◽  
Temur Khujanazarov ◽  
...  

With continued population growth, increasing staple crop production is necessary. However, in dryland areas, this is negatively affected by various abiotic stresses, such as drought and salinity. The field screening of 10 improved genetic lines of pear millet originating from African dryland areas was conducted based on a set of agrobiological traits (i.e., germination rate, plant density, plant maturity rate, forage, and grain yields) in order to understand plant growth and its yield potential responses under saline environments. Our findings demonstrated that genotype had a significant impact on the accumulation of green biomass (64.4% based on two-way ANOVA), while salinity caused reduction in grain yield value. HHVBC Tall and IP 19586 were selected as the best-performing and high-yielding genotypes. HHVBC Tall is a dual purpose (i.e., forage and grain) line which produced high grain yields on marginal lands, with soil salinization up to electrical conductivity (EC) 6–8 dS m−1 (approximately 60–80 mM NaCl). Meanwhile, IP 19586, grown under similar conditions, showed a rapid accumulation of green biomass with a significant decrease in grain yield. Both lines were tolerant to drought and sensitive to high salinity (above 200 mM NaCl). The threshold salinity of HHVBC Tall calculated at the seedling stage was lower than that of IP 19586. Seedling viability of these lines was affected by oxidative stress and membrane peroxidation, and they had decreased chlorophyll and carotenoid biosynthesis. This study demonstrated that ionic stress is more detrimental for the accumulation of green and dry biomass, in combination with increasing the proline and malonic dialdehyde (MDA) contents of both best-performing pearl millet lines, as compared with osmotic stress.

1990 ◽  
Vol 41 (3) ◽  
pp. 449 ◽  
Author(s):  
GK McDonald

The growth and yield of two lines of uniculm barley, WID-103 and WID-105, were compared over a range of sowing rates (50-400 kg/ha) with the commercial varieties Galleon and Schooner. The experiments were conducted at Strathalbyn, S.A., in 1986, 1987 and 1988 and at the Waite Agricultural Research Institute in 1987. A third tillered variety, Clipper, was included in the comparison in 1988. Over the three years plant populations measured early in the season ranged from 39/m2 to 709/m2, and grain yields from 97 to 41 1 g/m2. Dry matter production at ear emergence increased with greater plant density, and both the tillered varieties and the uniculm lines showed similar responses to higher sowing rates. At maturity, dry matter production of the tillered barleys was greater than or equal to that of the uniculms and the harvest indices (HIs) of the two types were similar. Consequently, grain yields of the tillered types were greater than or equal to the yields of the uniculms. Over the four experiments the tillered varieties had a 6% higher yield. The number of ears/m2 was the yield component most affected by plant density in both the tillered and uniculm barleys. The uniculm lines had more spikelets/ear, but tended to set fewer grains/spikelet and produce smaller kernels. The experiments failed to demonstrate any advantage of the uniculm habit to the grain yield of barley. These results differ from previous experiments that showed that a uniculm line, WID-101, had a higher yield than the tillered variety Clipper. It is suggested that the uniculm habit per se was not the cause of this higher yield, but its higher HI resulted in it outyielding Clipper. Current varieties, however, have HIs similar to the uniculm lines and yield equally to or more than the uniculm barleys examined. To further improve the grain yield of uniculm barley, greater dry matter production is necessary as the HIs of these lines are already high.


Soil Research ◽  
2011 ◽  
Vol 49 (7) ◽  
pp. 559 ◽  
Author(s):  
Y. P. Dang ◽  
R. C. Dalal ◽  
M. J. Pringle ◽  
A. J. W. Biggs ◽  
S. Darr ◽  
...  

Salinity, sodicity, acidity, and phytotoxic concentrations of chloride (Cl–) in soil are major constraints to crop production in many soils of north-eastern Australia. Soil constraints vary both spatially across the landscape and vertically within the soil profile. Identification of the spatial variability of these constraints will allow farmers to tune management to the potential of the land, which will, in turn, bring economic benefit. For three cropping fields in Australia’s northern grains region, we used electromagnetic induction with an EM38, which measures apparent electrical conductivity of the soil (ECa) and soil sampling to identify potential management classes. Soil Cl– and soluble Na+ concentrations, EC of the saturated extract (ECse), and soil moisture were the principal determinants of the variation of ECa, measured both at the drained upper limit of moisture (UL) and at the lower limit (LL) of moisture extracted by the crop. Grain yield showed a strong negative relation with ECa at both UL and LL, although it was stronger for the latter. We arrive at a framework to estimate the monetary value of site-specific management options, through: (i) identification of potential management classes formed from ECa at LL; (ii) measurement of soil attributes generally associated with soil constraints in the region; (iii) grain yield monitoring; and (iv) simple on-farm experiments. Simple on-farm experiments suggested that, for constrained areas, matching fertiliser application to realistic yield potential, coupled to gypsum amelioration, could potentially benefit growers by AU$14–46/ha.year (fertiliser) and $207/ha.3 years (gypsum).


1986 ◽  
Vol 37 (3) ◽  
pp. 219 ◽  
Author(s):  
WK Anderson

Eight spring bread wheat cultivars (Triticum aestivum L.), differing widely in their nominal yield component characteristics, were tested under rain-fed conditions for three years at sowing densities ranging from 50 to 800 seeds m-2. The objectives of the experiments were to estimate the relationship between grain yield and particular yield components, the expression of plant type (yield components) in relation to plant density, and the plant population x cultivar interaction for grain yield over a range of seasons in a given environment. The 'optimum' plant population (at maximum grain yield) varied over 30-220 plants m-2, depending on season and cultivar. In general, variation in the 'optimum' population was greater between seasons for a given cultivar than between cultivars within seasons. The relationship between grain yield and yield components was examined at the 'optimum' population rather than at an arbitrary population at which grain yield may have been suboptimal for some cultivars or seasons. Grain yields at the optimum populations for the various cultivar x season combinations were positively related to culms m-2, spikes m-2 and seeds m-2. They were not clearly related to culm mortality (%). When averaged across seasons, cultivar grain yields were positively related to harvest index, but the general relationship was not so clear when seasons and cultivars were examined individually. Spike size (seeds spike-I or spike weight) and seed size were also not clearly related to grain yield at the 'optimum' population, and it was thus postulated that the production and survival of large numbers of culms, which in turn led to large numbers of seeds per unit area, were the source of large grain yields. Some interactions were found between yield components and plant population for some cultivars that could have implications for plant breeders selecting at low plant densities. The implications for crop ideotypes of the individual plant characters at the 'optimum' population are also discussed. Interactions between cultivars and plant populations implied that some cultivars required different populations to achieve maximum yields in some seasons. There was a tendency for larger yields to be achieved from cultivar x season combinations where the optimum population was larger, which suggested that commercial seed rates should be re-examined when changes to plant types or yield levels are made.


2015 ◽  
Vol 66 (1) ◽  
pp. 23 ◽  
Author(s):  
Craig Scanlan ◽  
Ross Brennan ◽  
Gavin A. Sarre

Changes in soil fertility following long periods of crop production in the south-west of Western Australia (WA) may have implications for phosphorus (P) fertiliser recommendations for wheat production. When the sandy soils of the region were first cleared for agricultural production, they were typically marginally acidic to neutral, with soil extractable-P levels inadequate for crop production. Recent surveys have shown that 87% of soils in south-west WA exceed the critical soil extractable-P level required for 90% of maximum grain yield, and ~70% of soils have a surface-soil pHCa <5.5. There has also been a shift towards a high frequency of wheat in the crop sequence. We conducted a field experiment to begin to quantify the importance of the interactions between soil pH and crop sequence on wheat response to P fertiliser. For grain yield, the magnitude of the response was greatest for rate of P applied, followed by lime treatment and then crop sequence. There were no interactions between these treatments. Our analysis of the grain-yield response to rates of P fertiliser showed no significant difference between the shape of the grain-yield response curve for treatments with and without lime. However, we did find a significant interaction between lime treatment and rate of P fertiliser applied for shoot P concentration and that soil P was more plant-available in the +lime than the –lime treatment. There is justification for making realistic adjustments to yield potential based on soil pH or crop sequence, although further work is required to determine whether the shape of the grain-yield response curve varies with these two factors.


2017 ◽  
Vol 101 (2) ◽  
pp. 185-202
Author(s):  
Johanie Rivera-Zayas ◽  
David Sotomayor-Ramírez ◽  
Ricardo Barnes

Nitrogen (N) is possibly the most limiting nutrient for crop production on the southern semi-arid coast of Puerto Rico. In efforts to improve inbred maize (Zea mays L.) grain yield, fertilizer N is sometimes aggressively managed. In this paper, we report on the results of a field experiment that evaluated the effect of six rates of fertilizer N (0, 34, 68,102,135 and 203 kg N/ha) and of cowpea (Vigna unguiculata cv. Iron-clay), planted as a cover crop during the offseason, on inbred maize grain yield. The soil was Jacaguas series (Loamy-skeletal, mixed, superactive, isohyperthermic Fluventic Haplustolls) on the Dow Agrosciences experimental farm in Santa Isabel, Puerto Rico. Cowpea was planted on 13 July 2013 and incorporated into the soil on 20 September 2013. An inbred maize line was planted on 19 December 2013 and harvested on 19 March 2014 at a plant density of 51,645 plants per hectare. Irrigation was provided via drip system, and fertilizer N was applied at three different stages during the growing season: at emergence, 21 and 37 days after planting. Measurements of plant height, chlorophyll readings using SPAD-502® and GreenSeeker®, and leaf N concentration were used as indicators of treatment response and N sufficiency. The maximum grain yield of 2,918 kg/ha was attained with the fertilizer N rate of 68 kg N/ha. The cowpea cover crop rotation did not affect grain yield (P>0.05). Plant height, and measurements by SPAD-502® and GreenSeeker® provided adequate indicators of crop N sufficiency during the vegetative stages V6 to V12, with optimum values of 149 cm, 46, and 0.67 NDVI, respectively, 52 days after planting with an application of 68 kg N/ ha. Crop response to fertilizer N occurred at a lower rate than in previous studies and those occurring under conventional commercial conditions. Other factors related to fertilizer N management, such as sources, placement and timing of application might be as important for grain yield improvement of inbred maize.


Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 634-639 ◽  
Author(s):  
Deirdre Lemerle ◽  
Birgitte Verbeek ◽  
Neil E. Coombes

The influence of wheat variety on the dose-response of annual ryegrass to diclofop-methyl (POST) was examined in the field in 1992 and 1993 in southern New South Wales, Australia. The aim was to determine if planting a strongly competitive variety of wheat improved control of annual ryegrass at reduced doses of diclofop-methyl. Suppression of ryegrass was dependent on herbicide dose, season, and wheat variety. In the absence of herbicide, dry matter (DM) production of annual ryegrass at 300 plants m−2at anthesis was 500 g ha−1with Dollarbird and Katunga compared to 1000 g ha−1with Rosella or Shrike in 1992. In 1993, DM was approximately 150 g ha−1with Dollarbird or Katunga, and 350 g ha−1with Shrike or Rosella. Ryegrass DM was reduced by diclofop-methyl to a greater extent, relative to the weedy unsprayed controls, with less competitive varieties Rosella and Shrike than with the more competitive Dollarbird or Katunga. Diclofop-methyl at 0.28 kg a.i. ha−1reduced DM of ryegrass growing with Katunga to less than 100 g m−2in 1992, compared to more than 200 g m2with the other varieties. In 1993, diclofop-methyl was more effective on ryegrass, and the same dose reduced ryegrass DM to almost zero in all varieties. Grain yields in unsprayed weedy controls of Dollarbird and Katunga were reduced approximately 20% by annual ryegrass compared with yields achieved with herbicides in both years. Yields of Rosella and Shrike in the unsprayed controls were reduced about 40% in 1992 and 60% in 1993. Only small increases in grain yields of all varieties occurred from diclofop-methyl doses above 0.13 kg a.i. ha−1. Poorly competitive varieties were dependent on herbicides to achieve grain yield potential and had a greater risk of weed survival when herbicide efficacy was reduced. In contrast, strongly competitive varieties, likely to retard build-up of weed seed in the soil, are less dependent on herbicides to achieve grain yield potential, and therefore result in reduced weed control cost.


Author(s):  
O B Bello

Optimum plant population is very important in enhancing high and stable grain yield especially in quality protein maize (QPM) production. A field trial was therefore conducted to compare the performance of six hybrids (three each of QPM and normal endosperm) at three population densities using a split-plot design at the sub-station of the Lower Niger River Basin Development Authority, Oke-Oyi, in the southern Guinea savanna zone of Nigeria during the 2010 and 2011 cropping seasons. Plant population -1 densities (53,333, 66,666, and 88,888 plants ha ) constituted the main plots and the six hybrids were assigned to the subplots, replicated three times. Our results showed a differential response of maize -1 hybrids to high densities, with plant populations above 53,333 plants ha reduced grain yield, and this is more pronounced in QPM than normal endosperm hybrids. This is contrary to the results observed in many other countries. This might be that the hybrids were selected in low yield potential area at low plant densities, and hence not tolerant to plant density stress. It may also be due to low yield potential of the experimental site, which does not allow yield increases at high plant densities. Though normal endosperm hybrids 0103-11 and 0103-15 as well as QPM Dada-ba were superior for grain yield among -1 the hybrids at 53,333 plants ha , hybrid 0103-11 was most outstanding. Therefore, genetic improvement of QPM and normal endosperm hybrids for superior stress tolerance and high yield could be enhanced by selection at higher plant population densities.


2001 ◽  
Vol 136 (3) ◽  
pp. 291-299 ◽  
Author(s):  
J. V. D. K. KUMAR RAO ◽  
C. JOHANSEN ◽  
Y. S. CHAUHAN ◽  
Y. S. CHAUHAN ◽  
V. K. JAIN ◽  
...  

The response of eight long-duration pigeonpea [Cajanus cajan (L) Millsp.] genotypes to irrigation was studied at Gwalior in Central India during the 1990–91, 1991–92 and 1992–93 growing seasons on an Inceptisol. The crop was grown at two spacings as it was expected that crop density could interact with the crop's ability to extract soil moisture. The irrigation treatment received furrow irrigation four times during the 1990–91 and 1992–93 seasons and twice during the 1991–92 season. Grain yields of all genotypes were 11 % higher when planted at higher density than at low density. There was a differential variation in yield and harvest index among genotypes due to season but not due to spacing and irrigation suggesting the validity of the present approach of testing genotypes under optimum conditions. Grain yield declined by 21 % from the 1990 to 1992 season. The decline was > 1 t/ha in some cultivars (ICPL 366, GW3), and between 0·5 and 1·0 t/ha in others (NP [WR] 15, ICP 87143 and ICPL 84072). In others (Bahar, ICP 9174, ICP 8860) the yield fluctuation was < 0·5 t/ha. The genotypes' mean yields were as high as 2·7 t/ha for ICPL 87143, ICPL 84072 and ICPL 366. There was a significant reduction in both grain yield (16 %), and also above-ground plant dry mass (18 %) due to soil moisture limitation in the unirrigated treatment. Both the above-ground plant dry mass and grain yields were significantly more at high plant density than at lower plant density especially with irrigation. The genotypes were found to differ in their response to production environment (irrigation, spacing and to the undefined differences of the 3 years). Genotypic variation in yield within a production environment was found to vary in relation to changes in harvest index and across environment (irrigation, seasons) due to variation in total dry matter production. A lack of negative relationship between the total dry matter and harvest index suggests the possibility of optimizing both for obtaining higher yield from long-duration genotypes.


2001 ◽  
Vol 31 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Luís Sangoi

Maize is the agronomic grass species that is most sensitive to variations in plant density. For each production system, there is a population that maximizes grain yield. This article presents an overview of the factors that affect optimum plant population, emphasizingthe effects of dense stands on ear development and discussing important changes in plant traits that have contributed to increase the tolerance of modern hybrids to high plant densities. Population for maize maximum economic grain yield varies from 30,000 to over 90,000pl.ha-1, depending on water availability, soil fertility, maturity rating, planting date and row spacing. When the number of individuals per area is increased beyond the optimum plant density, there is a series of consequences that are detrimental to ear ontogeny and result in barrenness. First, ear differentiation is delayed in relation to tassel differentiation. Later-initiated earshoots have a reduced growth rate, resulting in fewer spikelet primordia transformed into functional florets by the time of flowering. Functional florets extrude silks slowly, decreasing the number of fertilized spikelets due to the lack of synchrony between anthesis and silking. Limitations in carbon and nitrogen supply to the ear stimulate young kernel abortion immediately after fertilization. Availability of earlier hybrids, with shorter plant height, lower leaf number, upright leaves, smaller tassels and better synchrony between male and female flowering time has enhanced the ability of maize to face high plant populations without showing excessive barrenness. Improved endurance in high stands has allowed maize to intercept and use solar radiation more efficiently, contributing to the remarkable increase in grain yield potential experienced by this crop.


2021 ◽  
Vol 42 (5) ◽  
pp. 2651-2668
Author(s):  
Denis Piazzoli ◽  
◽  
Moryb Jorge Lima da Costa Sapucay ◽  
André Mateus Prando ◽  
João Alberto de Oliveira Júnior ◽  
...  

An appropriate combination of plant density with nitrogen (N) fertilization can optimize corn growth and increase grain yields. This study evaluated the effects of nitrogen topdressing rates and plant density levels on the agronomic performance of corn. The early hybrid DKB 240 YG, with high yield potential and stability, was evaluated in two summer crops in Mauá da Serra, Paraná (950 m asl), in a Cfb climate, on a Rhodic Eutrudox. The experiment was arranged in randomized complete blocks and subdivided plots with four replications. The plant densities (60,000; 75,000; 90,000 and 105,000 plants ha-1) were assessed in the plots and the nitrogen (ammonium nitrate 32% N) topdressing rates (0, 60, 120, 180 and 240 kg ha-1) in the subplots. The stem diameter, plant height, ear insertion height and grain yield were evaluated. The stem diameter, plant height, ear insertion height and grain yield were influenced by the interaction between plant density and nitrogen topdressing under the tested high-altitude edaphoclimatic conditions. The stem diameter of corn plants decreased due to the increase in plant density whereas nitrogen topdressing attenuated this reduction. Maximum plant height was observed at a density of 75,000 plants ha-1 associated with a topdressing of 169 kg ha-1 of N, and highest ear insertion at 60,000 plants ha-1 and 168 kg ha-1 of N. Corn yield was highest at a density of 105,000 plants ha-1 associated with a topdressing of 185 kg N ha-1 of N.


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