scholarly journals Seasonal Differences in Growth, Photosynthetic Pigments and Gas Exchange Properties in Two Greenhouse Grown Maize (Zea Mays L.) Cultivars

2014 ◽  
Vol 73 (2) ◽  
pp. 333-345 ◽  
Author(s):  
Iqbal Hussain ◽  
Abdul Wahid ◽  
Rizwan Rasheed ◽  
Hafiz Muhammad Akram

Abstract The greenhouse (GH) effect has emerged as a major factor in changing cropping patterns and limiting crop yields. This study was conducted to determine the comparative growth and photosynthetic responses of selected heat-resistant (cv. Sadaf) and heat-susceptible (cv. Agatti-2002) cultivars of maize to simulated GH conditions during spring and autumn seasons at seedling, silking and grain filling stages in 2007. Fifteen day old plants were shifted to plexiglass-fitted canopies to create GH conditions and data were recorded at each growth stage. The results revealed that the seasons, GH conditions and cultivars had large effects on plant growth and photosynthetic attributes. Simulated GH conditions increased the canopy temperature 4-7 °C in spring and 3-5 °C in autumn, but increased relative humidity by 2-3% in spring and 5-9% in autumn season. Although GH reduced the growth of both cultivars, shoot dry mass was reduced more in spring grown heat-susceptible maize at all growth stages. Although the cultivars showed a decrease in growth and photosynthesis, GH conditions resulted in less damage to cv. Sadaf than cv. Agatti-2002 in both seasons. Major indicators of sensitivity to GH effect were loss of chlorophyll b and carotenoids, reductions in net photosynthesis and stomatal conductance, and possibly reduced ability of Rubisco to fix CO2 in sensitive maize.

2019 ◽  
Vol 18 (1) ◽  
pp. 61-73
Author(s):  
LUIS SANGOI ◽  
FERNANDO PANISON ◽  
MURILO MIGUEL DURLI ◽  
LUCIELI SANTINI LEOLATO ◽  
ANTONIO EDUARDO COELHO ◽  
...  

RESUMO – O fracionamento da adubação nitrogenada é uma estratégia que pode aumentar o acúmulo de massa nosgrãos do milho. Este trabalho objetivou avaliar os efeitos do parcelamento da cobertura nitrogenada sobre o acúmulode fitomassa nas folhas, colmos e grãos após o espigamento do milho. O experimento foi implantado em Lages-SC.Foram testados dois híbridos (P30F53YH e P1680YH) e seis sistemas de aplicação do nitrogênio: testemunha semN, todo N aplicado em V5, V10 ou VT (pendoamento), ½ N em V5 + ½ N em V10, 1/3 N em V5 + 1/3 N em V10 +1/3 N em VT. A dose de N foi de 300 kg ha-1. Avaliou-se o acúmulo de fitomassa aos 0, 14, 28, 42, 56 e 70 dias apóso espigamento. A massa seca dos grãos dos dois híbridos aumentou linearmente em todos os sistemas testados. Asmaiores taxas de incremento (2,4 a 2,7 g dia-1) foram obtidas com a aplicação integral de N em V5 e as menores (1,5a 1,6 g dia-1) na testemunha. O fracionamento da adubação nitrogenada de cobertura em três estádios fenológicos nãoaumentou a massa dos grãos, em relação à fertilização feita integralmente em V5 ou V10.Palavras-chave: Zea mays, enchimento de grãos, cultivares, fenologia, nitrogênio. MAIZE DRY MASS ACCUMULATION AFTER SILKING AS AFFECTEDBY THE SPLITTING OF NITROGEN SIDE-DRESS FERTILIZATIONABSTRAT- The splitting of nitrogen fertilization is a strategy that can increase kernel dry mass accumulation of maize.This work was carried out aiming to evaluate the effects of splitting nitrogen side-dress fertilization on leaf, stem andgrain dry mass accumulation after maize silking. The experiment was set in Lages, SC, South of Brazil. Two hybrids(P30F53YH and P1680YH) and six nitrogen fertilization systems were tested: control without N, all N side-dressed atV5, V10 or VT (tasseling), ½ N at V5 + ½ N at V10, 1/3 N at V5 + 1/3 N at V10 + 1/3 N at VT. Nitrogen rate was 300kg ha-1. Dry mass accumulation was determined at 0, 14, 28, 42, 56 and 70 days after silking. The kernel dry mass ofboth hybrids increased linearly at all six N fertilization systems. The highest increment rates (2.4 to 2.7 g day-1) wereachieved when all N was side-dressed at V5. The lowest rates (1.5 to 1.6 g day-1) were registered in the control. Thesplitting of nitrogen side-dress fertilization in three growth stages did not increase kernel dry mass, when compared tothe fertilization carried out entirely at V5 or V10.Keywords: Zea mays, grain filling, hybrids, phenology, nitrogen.


2019 ◽  
Vol 56 (2) ◽  
pp. 263-279 ◽  
Author(s):  
Marzena Iwańska ◽  
Michał Stępień

SummaryDrought reduces crop yields not only in areas of arid climate. The impact of droughts depends on the crop growth stage and soil properties. The frequency of droughts will increase due to climate change. It is important to determine the environmental variables that have the strongest effect on wheat yields in dry years. The effect of soil and weather on wheat yield was evaluated in 2018, which was considered a very dry year in Europe. The winter wheat yield data from 19 trial locations of the Research Center of Cultivar Testing (COBORU), Poland, were used. Soil data from the trial locations, mean air temperature (T) and precipitation (P) were considered as environmental factors, as well as the climatic water balance (CWB). The hydrothermal coefficient (HTC), which is based on P and T, was also used. The effect of these factors on winter wheat yield was related to the weather conditions at particular growth stages. The soil had a greater effect than the weather conditions. CWB, P, T and HTC showed a clear relationship with winter wheat yield. Soil data and HTC are the factors most recommended for models predicting crop yields. In the selection of drought-tolerant genotypes, the plants should be subjected to stress especially during the heading and grain filling growth stages.


2016 ◽  
Vol 54 (2) ◽  
pp. 257-272 ◽  
Author(s):  
XIAOYU ZHANG ◽  
XIYING ZHANG ◽  
SUYING CHEN ◽  
HONGYONG SUN ◽  
LIWEI SHAO ◽  
...  

SUMMARYSelecting high-yielding cultivars under drought is an important practice to improve crop production. Canopy temperature (T) shows a relative reliable association with grain yield. In this study, we compared the suitability of canopy T and other agronomic as well as physiological traits associated with grain yield under different water regimes. Field experiments over two seasons (2011–2012 and 2012–2013) were carried out under three water regimes, represented about 64, 76 and 89% of potential evapotranspiration, with 16 local winter wheat (Triticum aestivum L.) cultivars in each season. Results showed that cultivars with higher yield usually performed consistently lower canopy T under three water regimes, while the relationships of grain yield with other agronomic or physiological traits were more influenced by soil moisture. In addition, the relationship between canopy T and grain yield varied with different growth stages: From the time of heading to early grain filling stages, a more significant negative linear relationship (p < 0.001) existed under the three irrigation levels.


2019 ◽  
Vol 11 (11) ◽  
pp. 23
Author(s):  
Fabio Rodrigues Ramos ◽  
Antonio Lucineudo de Oliveira Freire

This study aimed to investigate the gas exchange, growth and biomass production of Cnidoscolus quecifolius fertilized with potassium and submited to different water conditions. The experiment was conducted in a completely randomized design, with 4 replications and two plants per experimental unit, with treatments arranged in factorial scheme 3 &times; 4, corresponding to three levels of potassium (0 (control), 97.5 and 195 mg dm-3 K) and four levels of water (100% (control), 75%, 50% and 25% of pot capacity). Growth (height, shoot diameter, leaf area, and dry mass) and physiogical parameters (water potencial (&Psi;w), stomatal conductance (gs), transpiration rate (E), net photosynthesis (A), CO2 intercelular concentration (Ci), carboxylation efficiency (A/Ci), and intrinsic water use efficiency (A/E). Increase in potassium promoted rise in &Psi;w, gs, E, and A. However, it not influenced the growth parameters, except roots dry mass. Reduction in water levels reduced &Psi;w, gs, E and A, growth and dry matter production of plants. It is recommended that the substrate moisture level of 75% of the pot capacity in the early growth stages of faveleira seedlings.


2015 ◽  
Vol 41 (4) ◽  
pp. 548 ◽  
Author(s):  
Dong-Ling ZHANG ◽  
Hong-Na ZHANG ◽  
Chen-Yang HAO ◽  
Lan-Fen WANG ◽  
Tian LI ◽  
...  

2017 ◽  
Vol 30 (2) ◽  
pp. 412-419 ◽  
Author(s):  
ARTHUR BERNARDES CECÍLIO FILHO ◽  
ALEXSON FILGUEIRAS DUTRA ◽  
GILSON SILVERIO DA SILVA

ABSTRACT The intensive cultivation of vegetables with frequent chemical fertilization may cause accumulation of nutrients in the soil. This, in turn, may reduce crop yields and damage the environment due to contamination of ground water and rivers. Thus, to increase the effects of P (0, 100, 200, 300 and 400 kg ha -1 of P2O5) and K (0, 60, 120, 180 and 240 kg ha-1 of K2O) doses on the growth and productivity of radish cultivars (Sakata 19 and Sakata 25) in a soil with high levels of these nutrients, two experiments were conducted in randomized blocks with the factors cultivars and doses arranged in a 2 x 5 factorial design with three replications. Number of leaves per plant, leaf area, shoot and root dry mass, total and commercial productivity, percentage of cracked roots and P and K contents in the plant and in the soil were evaluated. The Sakata 19 cultivar performed better than the Sakata 25 in both experiments. The fertilization with P or K did not influence the growth and the productivity of both radish cultivars. Therefore, both cultivars of radish evaluated do not need to be fertilized with P and K when planted in a Latosol with high levels of these nutrients.


1983 ◽  
Vol 63 (1) ◽  
pp. 235-241 ◽  
Author(s):  
J. A. IVANY ◽  
J. R. ENMAN

Forage corn (Zea mays L.) was grown successfully in Prince Edward Island by no-till planting the corn into standing cereal stubble 15–20 cm tall using a Buffalo no-till seeder. Planting with the slot-type shoe in a preliminary experiment in 1978 gave better forage yields than planting with a slice-type shoe mainly because of better plant population achieved. Subsequent experiments in 1979–1981 using the slot-type shoe to no-till plant corn in cereal stubble gave good forage yields when adequate weed control was provided with herbicide treatment. Best control of quackgrass (Agropyron repens L. Beauv.) and dandelion (Taraxacum officinale Weber) and crop yields was achieved with glyphosate + atrazine (1.5 + 2.5 kg a.i./ha) or amitrole + atrazine (3.4 + 2.5 kg a.i./ha) applied preemergence after seeding corn and before corn emergence. Control of quack grass and dandelion with glyphosate or amitrole used alone ranged from 71–80%, but paraquat alone did not provide any weed control. Addition of atrazine to paraquat, glyphosate, or amitrole gave improved control of quackgrass and dandelion and higher forage corn yields. Addition of 2.5 kg a.i./ha atrazine gave better results than use of 1.0 kg a.i./ha of atrazine.Key words: Forage corn, no-till seeding, glyphosate, atrazine, aminotriazole, paraquat


2000 ◽  
Vol 51 (7) ◽  
pp. 891 ◽  
Author(s):  
D. Villegas ◽  
N. Aparicio ◽  
M.M. Nachit ◽  
J. L. Araus ◽  
C. Royo

The relationships between various morphophysiological traits and yield were studied in durum wheat (Triticum durum Desf.) grown in Mediterranean conditions. Two sets of 22 genotypes were used. One was developed for semi-humid environments (TA-genotypes) and was cultivated in 22 trials around the Mediterranean basin with a mean yield across genotypes and environments of 4925 kg/ha. The other set was developed for drier conditions (CA-genotypes) and was cultivated in 15 trials, with a mean yield of 3501 kg/ha. Morphophysiological traits for each set were evaluated in 2 trials with contrasting water regimes conducted in north-eastern Spain: Lleida-rainfed (LR) and Lleida-irrigation (LI). Two kinds of traits were evaluated: developmental traits, including early vigour, plant height, and phenology (days from planting to heading and to maturity); and traits related to photosynthetic performance such as canopy temperature and chlorophyll content of the flag leaf, both measured during grain filling, and carbon isotope discrimination of mature grains. All the traits, measured in both Lleida trials, were related to the mean yield of the same genotypes across all the sites where they were cultivated. Yield measured at either of the 2 environments at Lleida was a much poorer predictor of genotype differences in mean yield than most of the traits. Nevertheless, the kind of environment where the morphophysiological traits were evaluated affected the performance of these traits as yield predictors. The combination of significant traits measured in the better environment (LI) explained 71% and 55% of genotype variability in yield within TA- and CA-genotypes, respectively, but only 56% and 27% when they were evaluated at LR. On the other hand, growing conditions of the yield trials was the main factor determining the best combination of traits. For TA-genotypes, larger yields were associated with shorter plants and higher carbon isotope discrimination (Δ) of grains, and to a lesser extent with higher early vigour and lower canopy temperature, whereas phenological traits made no contribution to explaining genotype differences in yield. For the CA-genotypes, higher yields were related to an earlier heading date or alternatively to a higher chlorophyll content during grain filling. A higher Δ in mature kernels also seems to be a positive trait.


MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 161-172
Author(s):  
ANANTA VASHISTH ◽  
DEBASISH ROY ◽  
AVINASH GOYAL ◽  
P. KRISHNAN

Field experiments were conducted on the research farm of IARI, New Delhi during Rabi 2016-17 and 2017-18. Three varieties of wheat (PBW-723, HD-2967 and HD-3086) were sown on three different dates for generating different weather condition during various phenological stages of crop. Results showed that during early crop growth stages soil moisture had higher value and soil temperature had lower value and with progress of crop growth stage, the moisture in the upper layer decreased and soil temperature increased significantly as compared to the bottom layers. During tillering and jointing stage, air temperature within canopy was more and relative humidity was less while during flowering and grain filling stage, air temperature within canopy was less and relative humidity was more in timely sown crop as compared to late and very late sown crop. Radiation use efficiency and relative leaf water content had significantly higher value while leaf water potential had lower value in timely sown crop followed by late and very late sown crop. Yield had higher value in HD-3086 followed by HD-2967 and PBW-723 in all weather conditions. Canopy air temperature difference had positive value in very late sown crop particularly during flowering and grain-filling stages. This reflects in the yield. Yield was more in timely sown crop as compared to late and very late sown crop.  


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